construction project engineering

CONSTRUCTION PROJECT

ENGINEERING

OCTAVIAN G. ILINOIU M.Sc., Ph.D., C.Eng., Lecturer

Department of Civil, Urban and Construction Engineering

Technical University of Civil Engineering of Bucharest

First Edition

-Bucharest 2004-

Construction Project Engineering

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PREFACE The Construction Project Engineering handbook is one of the Construction Engineering’s

main references, set up to assist students now enrolled within the framework of the Civil Engineering Department – English Section of the Technical University of Civil Engineering of Bucharest.

The purpose of this present handbook is to present fundamental and practical information in the field of plain and reinforced concrete, ensuring that works are undertaken in an orderly manner, as sequence, and follow the required principles of execution.

The handbook covers the whole project cycle for workers, equipment, materials, procedures, organization and quality control for concrete, reinforced concrete and precast concrete, serving as a reference guide for general contractors, construction managers, specialty subcontractors, estimators, project engineers, project managers, construction superintendents, scheduling engineers, sales engineers, or inspectors.

The content of this book is arranged in 6 chapters that are summarized below. Chapter 1. Concrete Mix Design, addresses the design requirements and methodology regarding selection and proportioning of ingredients for concrete to meet its desired properties for concrete works. Chapter 2. Rate of Concrete Placement Rough Estimate, presents basic information and specifies simplified means of estimating concrete rate of placement in formwork. Chapter 3. Concrete Formwork Design, specifies the materials, construction and removal of formwork and shoring made for wood and steel, including fundamental concepts and equations that are used to design and execute them. Chapter 4. Concrete Maturity, provides an overview regarding concrete maturity determination, outlining current experience in relation to using an effective and rational method in evaluating in-situ concrete strength at different ages. Chapter 5. Estimates, establishes guidance in describing methods, procedures, and formats for the preparation of construction project cost estimates, from planning phases through modification estimates during concrete construction. Chapter 6. Concrete Warehouse Structural Frame Erection, provides information concerning planning, detailing, sequencing and erection of concrete warehouse structural frames using precast reinforced and prestressed concrete members.

O.G. Ilinoiu, Bucharest 2004

ACKNOWLEDGMENTS These notes were originally based on ideas of Drs. Mihai Teodorescu and Radu Popa.

However, sketches, views, calculations and preference regarding comments are the writer's own. The author has written this presenting some positions as starting points for drafting a handbook rather than as the only positions that can be adopted.

The author gratefully acknowledges the assistance and support of a number of organizations, institutions, trade associations and manufacturers and who have provided information and photographs, and by permitting reproduction of certain elements of their material: American Concrete Institute - ACI, USA; American Society of Civil Engineers - ASCE, USA; American Society for Testing and Materials - ASTM, USA; APA. The Engineering Wood Association – USA; Building Science Insight - BSI, Canada; BUMAR – LABEDY S.A., Poland; Canadian Building Digest - CBD, Canada; Civil Engineering Corps Washington – CECW, USA; Cement and Concrete Association Australia; ECCON, ZIPACON, Romania; EFCO, USA; Heidelberg Cement AG, Germany; IPCT, Romania; International Council for Building Research and Documentation - CIB, Canada; International Union of Testing and Research Laboratories for Materials and Structures – RILEM; Institute for Research in Construction - IRC, Canada; IPC, Romania; LIEBHERR-Werk Nenzing Gmbh, Germany; MACON SA, Romania; National Research Council - NRCC, Canada; National Institute of Standards and Technology - NIST, USA; Preconstructa AEBTE, Greece; Prefabricate Vest, Romania; UBEMAR S.A., Romania; UMT Timisoara, Romania; TELEMAC, UBEMAR, Romania; US Army Corps of Engineers. Directorate of Military Programs, Engineering Division, USA and The Engineering Wood Association - APA, USA


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CONTENTS PREFACE ........................................................2 ACKNOWLEDGMENTS...............................2 CONTENTS.....................................................3 TABLE OF FIGURES ....................................4 TABLES ...........................................................5 CHAPTER 1. CONCRETE MIX DESIGN ..6

1.1. General Considerations ................................ 6 1.2. Designing the Concrete Mix......................... 6

1.2.1. Mix Design Procedure .......................... 6 1.2.2. Quality Requirements and Factors Affecting Designed Concrete ......................... 6

1.3. Determination of Job Parameters ................. 8 1.4. Example of Concrete Mix Design .............. 10 1.5. Appendix .................................................... 15 References ......................................................... 23

CHAPTER 2. RATE OF CONCRETE PLACEMENT ROUGH ESTIMATE .........25

2.1. General Considerations .............................. 25 2.2. Example 1................................................... 25 2.3. Example 2................................................... 25 References ......................................................... 26

CHAPTER 3. CONCRETE FORMWORK DESIGN..........................................................27

3.1. General Considerations .............................. 27 3.2. Modular Plywood Formwork ..................... 27 3.3. Shoring Members ....................................... 30 3.4. Formwork Principles .................................. 32

3.4.1. Formwork Loads ................................ 32 3.4.2. Formwork Pressures ........................... 32 3.4.3. Form Material Properties.................... 35

3.5. Wall, Slab Formwork and Shoring Systems Design ............................................................... 36

3.5.1. Slab Formwork and Shoring System Design........................................................... 36 3.5.2. Wall and Column Formwork Design.. 40

3.6. Example Working Drawings ...................... 43 3.7. Steel Modular Panel Formwork.................. 49

3.7.1. General Considerations....................... 49 3.7.2. Modular Steel Column Formwork...... 49 3.7.3. Example of Working Drawing............ 52

References ......................................................... 52 CHAPTER 4. CONCRETE MATURITY...53

4.1. General Considerations Regarding Concrete Maturity............................................................. 53 4.2. Maturity Index Method .............................. 53 4.3. Minimum Duration for Concrete Strength Attainment......................................................... 53 4.4. Critical Concrete Hardening Level............. 54

4.5. Rate of Concrete Hardening in Accordance with its Thermal History ....................................55 4.6. Concrete Curing Minimum Duration ..........55 4.7. Example ......................................................57 References..........................................................58

CHAPTER 5. ESTIMATES ........................ 59 5.1. General Considerations ...............................59 5.2. Types of Estimates ......................................59

5.2.1. Rough Estimating................................59 5.2.2. Detailed Estimate ................................60

5.3. Example of Project Estimates .....................62 5.3.1. Estimate Quantity of Materials, Labor and Cost for Concrete, Reinforcement and Formwork......................................................62 5.3.2. Estimate Calculation of Labor Consumption for Concrete, Reinforcement and Formwork Placement..............................64

5.4. Item tabulations of material consumption and labor costs for construction works...............65 References..........................................................70

CHAPTER 6. CONCRETE WAREHOUSE STRUCTURAL FRAME ERECTION....... 71

6.1. General Considerations ...............................71 6.2. Job Planning................................................72 6.3. Preliminary Execution Works .....................73

6.3.1. Standardized Prefabricated Reinforced and Prestressed Concrete Members...............73 6.3.2. Manufacturing, Transport and Storage of Precast Units .............................................90 6.3.3. Inspection of Units After Transport and Storage ..........................................................92 6.3.4. Unit Preparation ..................................92 6.3.5. Lifting Devices....................................92 6.3.6. Selection of Lifting Equipment ...........99

6.4. Erection of Precast Units...........................114 6.4.1. Sequence, Schemes and Procedures for Unit Erection ...............................................114 6.4.2. Unit Erection Detailing Sequences....115

6.5. Erection characteristics calculation...........116 6.6. Connections...............................................118 6.7. Inspection of Erection and Correction of Dimensional Tolerances...................................119 6.8. Construction Project Planning and Scheduling .......................................................120

6.8.1. Example Bar Chart Schedule – GantT Chart and Labor Schedule ...........................121 6.8.2. Example Network Schedules.............122

6.9. Health, Safety and Welfare Regulations ...123 6.10. Example Working Drawings...................124 References........................................................135

ABBREVIATIONS AND SYMBOLS ...... 135 CONVERSION TABLE ............................ 135


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TABLE OF FIGURES Figure 3-1. Typical plywood panel ....................................................................................................... 27 Figure 3-2 (a). Plywood panel formwork .............................................................................................. 28 Figure 3-2 (b). a,b,c and d- panel accessories ....................................................................................... 28 Figure 3-3. Typical steel telescopic joists. ............................................................................................ 30 Figure 3-4. Typical adjustable steel pipe shore (prop) .......................................................................... 31 Figure 3-5. Lateral pressure on wall form according to rate of concrete placement ............................. 33 Figure 3-6. Symbols for cross section of rectangular beam .................................................................. 36 Figure 3-7. Typical view of joist and prop ............................................................................................ 38 Figure 3-8. Schematic view of prop (shore).......................................................................................... 40 Figure 3-9. Pressure distribution of lateral face of panel ...................................................................... 40 Figure 3-10. Pressure of concrete on wall form .................................................................................... 41 Figure 3-11. Spacing between ties ........................................................................................................ 42 Figure 3-12. Typical assembly of steel modular panels ........................................................................ 49 Figure 3-13. Typical E75 scaffold, view and assembly phases a, b and c ............................................ 51 Figure 3-14. Assembly phases of steel modular column formwork a to g ............................................ 51 Figure 4-1. Temperature variation of concrete for different ages and freezing temperatures .............. 54 Figure 6-1. Transverse girder beam warehouse .................................................................................... 71 Figure 6-2. Longitudinal girder beam warehouse. ................................................................................ 72 Figure 6-3. Standardized catalog prefabricated reinforced and prestressed concrete members used for

ground floor warehouses............................................................................................................... 75 Figure 6-4 Typical trailers ..................................................................................................................... 90 Figure 6-5. Typical storage of reinforced and prestressed concrete members ...................................... 91 Figure 6-6. Typical prefabricated cup shaped foundations ................................................................... 91 Figure 6-7. Typical lifting devices for precast concrete members ........................................................ 92 Figure 6-8. Track-mounted crane .......................................................................................................... 99 Figure 6-9. Lorry mounted crane ........................................................................................................ 100 Figure 6-10. Self propelled crane ........................................................................................................ 100 Figure 6-11. Crane clearances ............................................................................................................. 101 Figure 6-12. AMT 950. Source: ECCON ........................................................................................... 102 Figure 6-13. DST-0285. Source: BUMAR – LABEDY S.A. ............................................................. 103 Figure 6-14. DST-0505. Source: BUMAR – LABEDY S.A. ............................................................ 104 Figure 6-15. DUT-0502. Source: BUMAR – LABEDY S.A............................................................. 105 Figure 6-16. TELEMAC HT – 15. Source: UBEMAR...................................................................... 106 Figure 6-17. TELEMAC HTA -7. Source: UBEMAR S.A. .............................................................. 107 Figure 6-18. LIEBHERR LHM 100. Source: LIEBHERR-Werk Nenzing Gmbh.............................. 108 Figure 6-19. LIEBHERR LHM 150. Source: LIEBHERR-Werk Nenzing Gmbh.............................. 109 Figure 6-20. LIEBHERR LHM 1060/2. Source: LIEBHERR-Werk Nenzing Gmbh ....................... 110 Figure 6-21. LIEBHERR LHM 1040/4. Source: LIEBHERR-Werk Nenzing Gmbh ....................... 111 Figure 6-22. LIEBHERR LHM 1030. Source: LIEBHERR-Werk Nenzing Gmbh........................... 112 Figure 6-23. LIEBHERR LHM 1160. Source: LIEBHERR-Werk Nenzing Gmbh............................ 113 Figure 6-24. Erection characteristics of columns ................................................................................ 116 Figure 6-25. General view typical assembly procedure of columns ................................................... 116 Figure 6-26. Erection characteristics of bridge beams ........................................................................ 116 Figure 6-27. Erection characteristics of girder beams......................................................................... 117 Figure 6-28. Erection characteristics of roof slabs .............................................................................. 117 Figure 6-29. General view typical assembly procedure of roof slabs ................................................. 118 Figure 6-30. Typical warehouse connections...................................................................................... 118


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TABLES Table A. Characteristic strength of concrete .......7 Table 1-1. Recommended concrete slump for

various types of construction ....................15 Table 1-2. Exposure class for concrete in

different environmental conditions...........15 Table 1-3. Minimum requirements for concrete

durability assurance according to exposure conditions..................................................16

Table 1-4. Minimum cement content for concrete durability assurance ..................................16

Table 1-5. Requirements for concrete durability assurance according to type of environment conditions..................................................17

Table 1-6. Grading classes ................................17 Table 1-7. Upper and lower limits of gradation 18 Table 1-8. Standard types of Portland cement...18 Table 1-9. Cement types according to Romanian

standards (SR)...........................................19 Table 1-10. Recommended types of cement used

for concrete works in normal exposure conditions..................................................20

Table 1-11. Recommended types of cements for plain and reinforced concrete works exposed to sea water and severe freezing .21

Table 1-12. Recommended types of cements for plain and reinforced concrete works subjected to aggressive waters..................21

Table 1-13. Estimated mixing water requirement for various slumps ....................................22

Table 1-14. Relative density..............................22 Table 1-15. Approximate volume of air-

entrainment according to maximum size aggregates .................................................22

Table 1-16. Maximum values for w/c ratio after preliminary tests (grade II concrete homogeneity) ............................................22

Table 1-17. Concrete strength at 28 days after preliminary tests for grade II homogeneity..................................................................23

Table 1-18. Values that will be subtracted or added to the recommended values for grade II ...............................................................23

Table 1-19. Concrete mix design parameters ....23 Table 3-1. Panel nominal dimensions ...............27 Table 3-2. Allowable spans “d” (m) between

joists in accordance with span and load....30 Table 3-3. Allowable axial load “P” (daN) on

shore in accordance with length. ..............32 Table 3-4. Characteristics of concrete pressure on

formwork ..................................................34

Table 3-5. Coefficient α according to rate of concrete placement. ................................. 35

Table 3-6. Combination of loads according to member .................................................... 35

Table 3-7. Nomenclature of symbols ............... 36 Table 3-8. Modular steel formwork components

................................................................. 50 Panel ................................................................. 50 Table 4-1 Recommended critical cold weather

maturity level for concrete (Mk)............... 54 Table 4-2. Recommended striking off maturity

level for concrete (Mβ) ............................. 54 Table 4-3. Values of coefficient kθi of

equivalency .............................................. 56 Table 4-4. Striking time for concrete formwork56 Table 4-5. Control chart for calculating the

concrete maturity index ........................... 57 Table 5-1. Estimate schedule............................ 60 Table 5-2. Concrete .......................................... 65 Table 5-3. Formwork........................................ 67 Table 5-4. Reinforcement ................................. 69 Table 6-1. Erection characteristics table........... 73 Table 6-2. Typical prefabricated ground floor

warehouse concrete members .................. 73 Table 6-3. Lifting devices for columns ............ 93 Table 6-4. Lifting devices for beams................ 94 Table 6-5. Lifting devices for beams and roof

slabs ......................................................... 95 Table 6-6. Universal lifting devices ................. 98 Table 6-8. Lifting Capacities for Telescopic

Boom DST-0285.................................... 103 Table 6-9. Lifting Capacities for Telescopic

Boom DST-0505.................................... 104 Table 6-10. Lifting Capacities for Telescopic

Boom DUT-0502 ................................... 105 Table 6-11. Lifting Capacities for Telescopic

Boom TELEMAC HT ........................... 106 Table 6-12. Lifting Capacities for Telescopic

Boom TELEMAC HTA -7 .................... 107 Table 6-13. Lifting Capacities for Telescopic

Boom LIEBHERR LHM 1060/2 ........... 110 Table 6-14. Lifting Capacities for Telescopic

Boom LIEBHERR LHM 1040/4 ........... 111 Table 6-15. Lifting Capacities for Telescopic

Boom LIEBHERR LHM 1030 .............. 112 Table 6-16. Lifting Capacities for Telescopic

Boom LIEBHERR LHM 1160 .............. 113


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CHAPTER 1. CONCRETE MIX DESIGN 1.1. GENERAL CONSIDERATIONS

Concrete is a conglomerate of hydraulic cement, sand, stone, and water. The sand and stone are dispersed particles in a multiphase matrix of cement paste. When mixed with water, the cement powder hydrates to form cement paste (through a chemical reaction called hydration), which is an interconnected network of solid and semi-solid phases that gives concrete its strength, forming a natural stone imitation, known as concrete. Within this process lies the key to a remarkable characteristic of concrete: it is plastic and malleable when freshly mixed, strong and durable when hardened. The key to achieving a strong, durable concrete rests in the careful selection and proportioning of its constituent ingredients.

1.2. DESIGNING THE CONCRETE MIX The necessary first step to be taken to design a concrete mix is to establish clearly the requirements that the mix design must meet. These generally include one or more of the followings: mechanical strength, durability, characteristics of concrete member, and special requirements specified by the project design.

1.2.1. MIX DESIGN PROCEDURE The mix design cannot be resolved totally analytically, it requires, after the

determination of job parameters (e.g. quantities of water, cement, aggregate, w/c ratio), calculation of weights, experimental adjutants (trial) tests on concrete for ensuring that it meets the design specifications.

With this information and the aid of tables or simple calculations, the quantities (kg) of cement, coarse aggregate, water, and entrained air required per cubic meter can be determined. The absolute volumes of the ingredients can be calculated and totaled. Based on a 1 m3 of mix, subtracting the total of the four ingredients from 1 will provide the absolute volume of the fine aggregate required. From the absolute volume, the mass of the fine aggregate can then be calculated.

The quantities of materials required for 1 m3 of concrete shall be estimated and trial batches of 30 l made based on the quantities calculated. If adjustments are necessary further batches should be made by keeping the quantity of water and aggregate constant and only by adjusting the cement content to produce the desired slump and compressive strength.

1.2.2. QUALITY REQUIREMENTS AND FACTORS AFFECTING DESIGNED CONCRETE

The physical characteristics, chemical composition, and the proportions of the ingredients from mix affect the properties of concrete, in its fresh and hardened state. When designing, we must consider the following quality requirements of concrete:

- Fresh concrete: air content, flow behavior (workability/consistency), bleeding, cement type, setting time, hydration heat limitation.

- Hardened concrete: strength at specified age - short term (e.g. initial pre stress force and long term), durability – environment / exposure (e.g. carbonation, chloride penetration, acid resistance, sulfate resistance), frost-thaw resistance, permeability (fluids, gas), resistance against early age cracking.

Factors to be considered regarding durability: - Choice of slump. - Environment conditions (dry, humid, humid with frost, marine and chemical

aggressiveness).


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- Exposure conditions (constructions protected against rain and humidity, frost-thaw saturated (no saturated) with water, exposure to water under pressure, exposed to marine or chemical environment etc.).

- Maximum size of aggregate. - w/c ratio. - Type of additive / admixture used. - Minimum cement content:

Factors to be considered: Watertightness (grades: 10

4P , 108P , 10

12P , 204P , 20

8P , 2012P – it may be tested by

measuring the flow through a saturated specimen, of 100 mm respectively 200 mm, subjected to pressure.

Freeze-thaw resistance G50, G100, G150. Proportioning relates to the following aspects: - Workability (regarding fresh concrete). - Durability, strength (regarding hardened concrete). - Economy by:

Minimizing the amount of cement and w/c ratio. Minimizing the amount of water, to reduce cement content, and to increase

strength durability. - Batch weights calculations. - Adjustments.

Factors to be considered when choosing aggregates: - Economical consideration:

Minimize water and cement, stiffest possible mix; Largest particle max size of aggregate, shape, surface texture; Optimize ratio of fine to coarse; Grading and its significance: consistency and strength.

- Size and shape of members: maximum size aggregate; - Physical properties: strength; - Exposure condition: air entraining or not, sulfate attack; - Maximum aggregate size: The largest maximum aggregate size that will conform to

limitations given below: Nominal maximum size aggregate (Dmax) should not be larger than:

Dmax ≤1/4 of narrowest dimension of structural member; ≤1/3 thickness of slab ≤1/6 reservoir wall thickness ≤spacing between re-bars – 5 mm

≤1,3 x concrete cover of re-bars ≤1/3 concrete pump piping

Factors to consider when choosing water to cement ratio: - Compressive strength is inversely proportional to w/c: - Economical consideration: minimize water and cement, stiffest possible mix. Table A. Characteristic strength of concrete Concrete grades (MPa)

C* 2,8/ 3,5

C 4/ 5

C* 6/ 7,5

C 8/ 10

C 12/ 15

C 16/20

C* 18/ 22,5

C 20/ 25

C 25/ 30

C* 28/ 35

C 30/ 37

C* 32/ 40

C 35/ 45

C 40/ 50

C 45/ 55

C 50/ 60

Characteristic strength of concrete Source: NE 012-1999 fc,28 cylinder 2,8 4 6 8 12 16 18 20 25 28 30 32 35 40 45 50 fc,28 cube 3,5 5 7,5 10 15 20 22,5 25 30 35 37 40 45 50 55 60 * concrete classes that remain effective until Romanian Design Codes come into effect (accordance Eurocode 2).


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1.3. DETERMINATION OF JOB PARAMETERS Step 1: Durability conditioning of concrete Environment conditions (table 1-2) ⇒ class of exposure

Requirements of grade and durability (table 1-3 and 1-4). 1. W/C ratio:

Table 1-3 ⇒ suggested w/c ratio. 2. Cement content:

Table 1-4 ⇒ suggested minimum cement content C (kg/m3). Step 2: Preliminary procedures for determining the quality mix proportions of concrete constituents

1. Slump: Table 1-1 ⇒ suggested slump T (mm).

2. Minimum cement content: Table 1-5 ⇒ suggested minimum cement content c (kg/m3).

3. Aggregates: a) Selection of aggregates by type (table 1-14). b) Nominal maximum size of aggregates:

Computed according to the following restrictions: Dmax ≤ minimum dimension of bearing member/4; Dmax ≤ thickness of slab/3; Dmax ≤ thickness of reservoir (tank) wall/6; Dmax ≤ minimum distance between re-bars – 5 mm; Dmax ≤ 1,3 x reinforcement concrete cover; Dmax ≤ diameter of pump hose/3 ~ 31 mm

4. Gradation of aggregate particles: Table 1-6 ⇒ suggested grading curve ⇒ table 1-7 ⇒ upper and lower gradation limits.

5. Cement: Table 1-10, 1-11, 1-12 ⇒ Recommended cement type and grade.

6. Water-cement maximum ratio: Table 1-5 ⇒ recommended water-cement maximum ratio. Step 3: Procedures for determining the batch weights for mix proportions of constituents

1. Estimate mixing water and air content: Table 1-13 ⇒ w (kg/m3)

Correction of water quantity according to maximum nominal size aggregate ⇒ w' = w x c (kg/m3). Table 1-15 ⇒ suggested volume of air-entrainment

2. Water-cement ratio: Table 1-16 ⇒ suggested w/c ratio.

Final adopted value of w/c = minimum value between (step 2.6. and step 3.2) 3. Cement:

cwwC/''= [kg/m3]

Final adopted value of C = maximum value between (step 2.5. and step 3.3) 4. Estimate coarse aggregate: (First estimate of aggregate weight) The total amount of dry aggregates will be calculated as follows:

Knowing that V = m / ρ


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V ag = V total – V water = V cement – V air Ag = ρag x (1000 – C/ρc - A'/ρa - p) [kg/m3]

Where: ρag = relative density of aggregates (2,7 kg/dm3); ρc = relative density of cement (3,0 kg/dm3);

p = void parameter (table 11), when not using additives, (when using additives the parameter will be computed according to laboratory tests).

5. Gradation of aggregate: Table 1-7 ⇒ percentage limits of aggregate passing.

The amount of aggregate for each grade is found as follows:

100

ppxAA 1iiggi

−−= (kg/m3)

Where: Ag = amount of aggregates (kg); pi = percent passing by mass through sieve "i"; pi-1= percent passing by mass through sieve "i-1";

6. Adjustment for moisture in aggregate:

100uxAA i

giΣ=Δ (l/m3)

Where: Agi = amount of aggregate form sieve "i' (kg); ui = free moisture of sieve "i" (%); n = total numbers of sieves. A* = A' - ∆A (l/m3)

The free amount of moisture form fine aggregates (UFA%), is calculated as follows:

100i

ginu

xAA Σ=Δ kg/m3

The free amount of moisture form coarse aggregates (UCA%), is calculated as follows:

100i

gipu

xAA Σ=Δ kg/m3

The total amount of free moisture is calculated as follows: pn AAA Δ+Δ=Δ kg/m3

Adjusted amount of water: A* = A' - ∆A (kg/m3) 7. Adjustment of total amount of aggregates by sieve sizes: The of total amount of aggregates by sieve sizes, is found as follows:

⎟⎠⎞

⎜⎝⎛ +=

100u1xAA i

gi*gi (kg/m3)

Where: Agi - amount of aggregate form sieve "i' (kg); ui = free moisture of sieve "i" (%). 8. Final adjustment of aggregate weight: The of total amount of aggregates, is found as follows: Ag* = ∆ Agi * (kg/m3)

Where: Ag* = adjusted amount of aggregate form sieve "i' (kg); n = number of sieves sizes.

Ag * = Σ A*gi kg/m3 9. Total mass of concrete produced: The total mass of concrete produced will be calculated as follows: ρ b = A* + C’ + Ag* ρ b will be compared with the value of normal weight concrete that ranges between 2160 to 2560 kg/m3


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1.4. EXAMPLE OF CONCRETE MIX DESIGN Design a normal weight concrete mix that is to test C 12/15 at 28 days, that will be located in definite site. Determine the correct amount of ingredients for the concrete mix in accordance to the following characteristics: A. Data required: 1. Specified concrete (grade/class): C 12/15 2. Characteristics of bearing member:

a) Type of bearing member: bearing walls. b) Minimum section (dimension) of concrete member: b = 200 mm c) Concrete cover of reinforcing bars: c = 25 mm d) Minimum spacing of reinforcing bars: D = 100 mm

3. Conditions (class) of exposure and environment conditions: Dry moderate environment, concrete member protected against weather or aggressive conditions.

4. Work conditions: Normal conditions, using plywood form panels. 5. Transport and placement of concrete: Transit mix trucks and concrete pumps. 6. Aggregates: Siliceous riverbed. 7. Relative density: 2.70 (kg/dm3) 8. Moisture content in aggregates: - F.A. (fine aggregate) (0 - 7 mm): uS = 2%; - C.A. (coarse aggregate) (7 - 71 mm): uG = 1%.

9. Grade of homogeneity: II. 10. Air content: 2% (20 dm3/m3). 11. Permeability grade: P10 4 12. Freeze thaw grade: G100

B. Durability conditioning of concrete:

From table 1-2, in accordance with the type environment conditions (moderate dry), we find the conditions (class) of exposure 1.a.

The concrete mix will be designed according to the requirements of grade and durability (table 1-3 and 1-4). The requirements for durability assurance will be specified according to rules that consider the concrete mix and the choosing of its components (cement type, maximum w/c ratio, permeability grade, freeze-thaw grade etc.). 1. W/C ratio:

From table 1-3, in accordance with the environmental conditions, concrete grade and permeability grade, results a suggested w/c ratio 0,65. 2. Cement content:

A minimum cement content is necessary to be adopted to assure no alkalinity reaction of concrete, a main condition for protection against re-bar corrosion and for workability assurance for a known w/c ratio. From table 4, in accordance with the exposure conditions and aggressiveness intensity, results the minimum cement content. C= 250 kg/m3. C. Preliminary procedures for determining the quality mix proportions of concrete constituents: 1. Concrete consistency (slump): From table 1-1, in accordance with the type of structural member (bearing wall), transport equipment (transit mix truck), technology of concrete placing (pump) and type of


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concrete (reinforced), results from item no. 3 the recommended consistency T3/T4 (slump 100 ±20 mm). 2. Minimum cement content: From table 1-5 we find the minimum cement content of 300 kg/m3, according to the type of concrete (reinforced) and the conditions of exposure (1.a.). 3. Aggregates: a) Selection of aggregates by type: natural or crushed aggregates. We will use natural riverbed aggregates with the relative density agρ = 2,7 kg/dm3 (see table 1-14). b) Nominal maximum size of aggregates:

Is computed according to the following restrictions: Dmax ≤ minimum dimension of bearing member/4; Dmax ≤ thickness of slab/3; Dmax ≤ thickness of reservoir (tank) wall/6; Dmax ≤ minimum distance between re-bars – 5 mm; Dmax ≤ 1,3 x reinforcement concrete cover; Dmax ≤ diameter of pump hose/3 ~ 31 mm

According to the assignments initial data: type of concrete member (bearing walls), minimum length of section being formed (b = 200 mm), minimum distance between re-bars (D = 100 mm), transport and placement of concrete and minimum concrete cover of reinforcing bars (c = 25 mm): D max ≤ 1/3 x c = 1/3 x 25 = 32,5 mm ; D max ≤ 1/4 x b = 1/4 x 200 = 50 mm ; D max ≤ D – 5 mm = 100 - 5 = 95 mm ; Pumpability D max = 31 mm. According to the exposure conditions (dry environment), the concrete cover of reinforcing bars do not condition the maximum size of aggregates. All these conditions have to be simultaneously respected, results Dmax ≤ 31 mm. We chose Dmax = 31 mm. c) Gradation of aggregate particles: From table 1-6 results the grading zone (I) according to the minimum cement content 300 kg/dm3. Knowing the grading curve (I) and the maximum size of aggregate 31 mm, from table 1-7.4. results the following upper and lower gradation limits: sieve 0 - 0,2 mm : recommended 10 - 15% : we chose 12%; sieve 0,2 – 1 mm : recommended 30 - 40% : we chose 33%; sieve 1 - 3 mm : recommended 40 - 50% : we chose 43%; sieve 3 - 7 mm : recommended 60 - 70% : we chose 63%; sieve 7 - 16 mm : recommended 80 - 90% : we chose 83%; sieve 16 –31 mm : recommended 95 - 100%: we chose 97%. 4. Cement: According to the exposure conditions (concrete surfaces protected against weather or aggressive conditions) and environment conditions (moderate dry) results the type of cement form table 1-10, conditioned by the type and section of concrete element (bearing wall) and concrete class (C 12/15). Recommended cement type CEM II A - 32,5 N. 5. Water-cement maximum ratio: From table 1-5, according to the type of concrete (reinforced) and the exposure conditions (1.a.) results the water-cement maximum ratio (w/c maximum = 0,65). D. Procedures for determining the batch weights for mix proportions of constituents 1. Estimate mixing water and air content: The estimated water quantity needed (w) is determined according to the concrete grade (C 12/15) and the slump (T3/T4).


12

From table 1-13, w = 200 l/m3 This quantity will be adjusted with a coefficient (c= 1) determined by the maximum aggregate size 31 mm, as follows:

w' = w x c = 200 x 1 = 200 l/m3 2. Water-cement ratio: From table 1-14, according to the concrete grade (C 12/15) and cement grade (32,5N), concrete homogeneity grade II, results the water: cement ratio A/C = 0,70. The value will be adjusted with a coefficient for crushed aggregates if it is necessary and the resulting value of A/C will be compared with the maximum value calculated of A/C, determined at section 2.5. From the two values the minimum one will be chosen A/C maxim = 0,65. 3. Cement: The cement quantity is calculated as follows: 308

65,0200

/'' ===CW

WC [kg/m3] >

minimum cement contents 250 and 300 kg/m3 (see section B and C). From the three values the maximum one will be chosen C = 308 kg/m3. 4. First estimate of aggregate weight: The total amount of dry aggregates will be calculated as follows:

Knowing that V = m / ρ: V ag = V total – V water - V cement – V air

Aag = ρag x (1000 – C/ρc - A'/ρa - p) [kg/m3] From table 1-15 the approximate volume of air-entrainment will be chosen according to maximum size aggregates. For 31 mm maximum size the mix will have 4,5 % air entrainment volume (4,5% = 45 dm3/m3).

Aag = 2.7 x (1000 – 308/3 – 200/1 - 45) = 1761.3 [kg/m3] Where: ρag = relative density of aggregates (2,7 kg/dm3); ρc = relative density of cement (3,0 kg/dm3);

p = void parameter (table 1-15), when not using additives, (when using additives the parameter will be computed according to laboratory tests).

5. Gradation of aggregate: According to the lower and upper limits of gradation recommended table 1-7.4, it can be determined the right amount of each grade of fine and coarse aggregate (this determination can be made by plotting the cumulative percent passing by mass through each sieve, see table 1-7.

The amount of aggregate for each grade is found as follows:

100

ppxAA 1iiggi

−−= (kg/m3)

Where: Ag = amount of aggregates (kg); pi = percent passing by mass through sieve "i"; pi-1= percent passing by mass through sieve "i-1"; First correction:

Sieve 0 - 0,2 mm; 12100 x 1761.3 = 211.35 kg/m3 ;

Sieve 0,2 – 1 mm; 33 − 12

100 x 1761.3 = 369.87 kg/m3 ;

Sieve 1 – 3 mm; 43 − 33

100 x 1761.3 = 176.13 kg/m3 ;

Sieve 3 –7 mm; 63 − 43

100 x 1761.3 = 352.26 kg/m3 ;

Sieve 7 – 16 mm; 83 − 63

100 x 1761.3 = 352.26 kg/m3 ;


13

Sieve 16 – 31 mm; 97 − 83

100 x 1761.3 = 246.58 kg/m3. Total: 1708.45 kg/m3 Second correction (to produce 1 m3 per trial batch the quantities must be adjusted):

Sieve 0 - 0,2 mm; 12100 x (1761.3-1708.45) = 6,4 kg/m3 ;

Sieve 0,2 – 1 mm; 33 − 12

100 x 52.84 = 10,8 kg/m3 ;

Sieve 1 – 3 mm; 43 − 33

100 x 52.84 = 5,4 kg/m3 ;

Sieve 3 –7 mm; 63 − 43

100 x 52.84 = 10,8 kg/m3 ;

Sieve 7 – 16 mm; 83 − 63

100 x 52.84 = 10,8 kg/m3 ;

Sieve 16 – 31 mm; 97 − 83

100 x 52.84 = 7,5 kg/m3. Total: 51,7 kg/m3 The correct masses according to corrections for achieving the total amount of aggregate required is 1829 kg/m3:

Sieve 0 - 0,2 mm; 211,35 + 6,4 = 217,75 kg/m3; Sieve 0,2 – 1 mm; 369,87 + 10,8 = 380,5 kg/m3; Sieve 1 – 3 mm; 176,13 + 5,4 = 181,53 kg/m3; Sieve 3 –7 mm; 352,26 + 10,8 = 363,06 kg/m3; Sieve 7 – 16 mm; 352,26 + 10,8 = 363,06 kg/m3; Sieve 16 – 31 mm; 246,58 + 7,5 = 254,08 kg/m3. Total: 1759,98 kg/m3 6. Adjustment for moisture in aggregate: The right adjustment of water will be found according to the exact free moisture of the aggregates, as follows:

100i

agiuxAA Σ=Δ (l/m3)

Where: Aagi = amount of aggregate form sieve "i' (kg); ui = free moisture of sieve "i" (%); n = total numbers of sieves. A* = A' - ∆A (l/m3) The free amount of moisture form fine aggregates (2%), is calculated as follows: ( ) 85,2206,36353,1815,380217,75

1002

100=+++=Σ=Δ x

uxAA i

gin kg/m3

The free amount of moisture form coarse aggregates (1%), is calculated as follows: ( ) 17,608,254363,06

1001

100=+=Σ=Δ x

uxAA i

gip kg/m3

The total amount of free moisture is calculated as follows: 02,29 6,17 22,85 =+=Δ+Δ=Δ pn AAA kg/m3

Adjusted amount of water: A* = A' - ∆A = 200 – 29,02 = 170,97 kg/m3 7. Adjustment of total amount of aggregates by sieve sizes: The of total amount of aggregates by sieve sizes, is found as follows:

⎟⎠⎞

⎜⎝⎛ +=

100u1xAA i

gi*gi (kg/m3)

Where: Aagi - amount of aggregate form sieve "i' (kg); ui = free moisture of sieve "i" (%).

Sieve 0 - 0,2 mm; 217 x (1+ 2

100 ) = 222,10 kg/m3;


14

Sieve 0,2 – 1 mm; 380,5 x (1+ 2

100 ) = 388,11 kg/m3 ;

Sieve 1 – 3 mm; 181,53 x (1+ 2

100 ) = 185,16 kg/m3 ;

Sieve 3 –7 mm; 363,06 x (1+ 2

100 ) = 370,32 kg/m3 ;

Sieve 7 – 16 mm; 363,06 x (1+ 1

100 ) = 366,69 kg/m3 ;

Sieve 16 – 31 mm; 254,08 x (1+ 1

100 ) = 256,62 kg/m3. Total: 1789,0 kg/m3

8. Final adjustment of aggregate weight: The of total amount of aggregates, is found as follows: Aag* = ∆ Aagi * (kg/m3) Where: Aag* = adjusted amount of aggregate form sieve "i' (kg); n = number of sieves sizes.

Aag * = Σ A*agi = 1789,0 kg/m3

9. Total mass of concrete produced: The total mass of concrete produced will be calculated as follows: ρ b = A* + C’ + Aag*

G b = A* + C’ + Aag* = 170,97 + 308 + 1789 = 2267,97 kg/m3 ρ b = 2335,9 kg/m3 will be compared with the value of normal weight concrete that ranges between 2160 to 2560 kg/m3 10. Summary of mix design:

Concrete class C 12/15 Batch percentage: 100 % Compressive strength at 28 days: 15 MPa Slump: Maximum 120 mm Minimum 80 mm Nominal maximum size of aggregate: 31 mm Cement type: CEM II A - 32,5N Water-cement ratio: 0.65 Concrete type: Reinforced Air content: 4.5 % Permeability: P10 4 Freeze-thaw: G100 Unit weight of aggregates: F.A. 1165,59 kg/m3 C.A. 623,97 kg/m3 Mass of batched concrete: ρc = 2268 kg/m3


15

1.5. APPENDIX Table 1-1. Recommended concrete slump for various types of construction

Consistency Item no.

Type of concrete member Type of Transport Grade Slump

(mm) 1 Plain or reinforced foundations /footings, massive

elements Truck, bucket, belt conveyor T2 30±10

2 Plain or reinforced footings, massive elements,slabs, columns, beams, walls.

Transit mix truck, bucket T3 70±20

3 Plain or reinforced footings, massive elements, slabs, columns, beams, walls, reservoirs placed by concrete pump

Transit mix truck T3/ T4

100±20

4 Members and small reinforced monolithic sections with difficulties while compacting

Transit mix truck, bucket T4 120±20

5 Concrete prepared with plasticizers or superplasticizers additives

Transit mix truck, bucket T4/ T5

150±30

6 Concrete prepared with superplasticizer additives Transit mix truck, bucket T5 180±30 Source: NE 012-1999 Table 1-2. Exposure class for concrete in different environmental conditions

Type of environment Type or location of structure 0 1 2

a). Moderate

Concrete surfaces protected against weather or aggressive conditions 1. Dry environment b). Severe Concrete surfaces exposed permanent to temperatures grater that 30 oC

a). Moderate

Concrete surfaces exposed to freezing whilst sheltered form severe rain or freezing whilst wet

2. Hummed environment

b). Severe

Concrete surfaces exposed to freezing whilst continuously submerged under water; Concrete surfaces exposed to condensation or alternant wetting and drying; Concrete surfaces exposed to continuous water pressure on one side

3. Hummed environment subjected to freezing and deicing salts

Concrete interior or exterior surfaces exposed to freezing and de-icing salts

1).Weak aggressive conditions

Concrete surfaces exposed permanent to sea water; Concrete surfaces situated over the variation level of the sea

a).No freezing 2).Intensive

aggressive conditions

Concrete surfaces situated over the variation level of the sea


Concrete surfaces exposed indirectly to marine environment Concrete surfaces exposed to freezing sheltered from wetting Concrete surfaces protected against weather without heating

4. M

arin

e en

viro

nmen

t

b).With freezing 2).Intensive

aggressive conditions

Concrete surfaces exposed to marine environment by alternant wetting, drying and salts. Concrete surfaces exposed industrial technological condensation of vapors.

a). Mild chemical aggressive environment b). Moderate chemical aggressive environment c). Severe chemical aggressive environment

5. C

hem

ical

ag

gres

sive

en

viro

nmen

t

d). Very severe chemical aggressive environment Source: NE 012-1999


16

Table 1-3. Minimum requirements for concrete durability assurance according to exposure conditions

Exposure conditions Concrete

grade min.

Permeability min.

Freeze-thaw min.

w/c max

a). Moderate 1. Dry environment b). Severe C 12/15 P4 - 0,65

a). Moderate C 16/20 P4 - 0,50 2. Hummed environment b). Severe C 18/22,5 P8 G100

(150) 0,45

3. Hummed environment subjected to freezing and deicing salts

P12 G150 0,40

1).Weak aggressive conditions a).No freezing 2).Intensive aggressive

conditions C 20/25 P8 - 0,45


4. M

arin

e en

viro

nmen

t

b).With freezing 2).Intensive aggressive

conditions C 25/30 P12 G100 0,40

a). C 18/22,5 P8 - 0,50 b). C 18/22,5 P8 - 0,50 c). C 18/22,5 P12 - 0,45

5. C

hem

ical

ag

gres

sive

en

viro

nmen

t

d). C 25/30 P12 - 0,45 Source: NE 012-1999 Table 1-4. Minimum cement content for concrete durability assurance

Minimum cement content (kg/m3) Exposure conditions

Aggressiveness grade Plain concrete Reinforced concrete

a - 150 250 1 b - 180 275 a - 200 290 2 b - 300 325

3 - 325 365 severe 300 325 a extreme 390 severe

350 300 325 4

b extreme 325 365

Natural aggressive water

Sulfate aggressiveness

Natural aggressive water

Sulfate aggressiveness

a mild 225 (180) 2401 260 2701

b moderate 300 (230) 3301

3002 325 3601 3402

c severe 350 (280) 3302 3103 390 3652

3503

d extreme 1* 4102(+) 3703

4502 4103

extreme 2* 4102(+) 4103

390 (+) 4502 (+) 4503

5

extreme 3*

350 (+) (280)

4103 4503 (+)

Note: * extreme 1, 2 or 3 according to the SO4 content mg/dm3. 1) Cement type CEM II A-S; Cement type H I; H II A-S; Cement type SR I; SR II A-S; (+) Special measures of protection; () the values between parentheses will be adopted for base layers or leveling concrete layers.

Source: NE 012-1999


17

Table 1-5. Requirements for concrete durability assurance according to type of environment conditions

Environment conditions for concrete table 1-2.

Item

no.

Concrete mix

components 1a 1b 2a 2b 3 4a1 4a2 4b1 4b2 5a 5b 5c 5d

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Water : Cement Ratio

Plain concrete

- 0,65 0,55 0,55 0,50 0,55 0,55 0,50 0,50 0,55 0,50 0,45 0,40

Reinforced concrete

0,65 0,60 0,55 0,50 0,50 0,50 0,50 0,45 0,45 0,55 0,50 0,45 0,40

1

Prestressed concrete

0,60 0,55 0,55 0,50 0,50 0,50 0,50 0,45 0,40 0,55 0,50 0,45 0,40

Minimum cement content (kg/m3). Plain concrete

150 300 250 300 350 350 350 350 350 350 350 400 450

Reinforced concrete

300 300 350 350 350 350 400 400 400 350 350 400 450

2


350 350 350 350 350 350 400 400 450 350 350 400 450

Percent of air entrained (%), min. Max. size aggregate 31 mm

- - 4 4 4 - - 4 4 - - - -

Size aggregate 16 mm

- - 5 5 5 - - 5 5 - - - -

3

Max. size aggregate 7 mm

- - 6 6 6 - - 6 6 - - - -

4 Frost resisting aggregates

- - Yes Yes Yes - - Yes Yes - - - -

Watertightness grade, min. Plain concrete

- P410 P410 P810 P410 P410 P810 P810 P410 P810 P1210 P1210

Reinforced concrete

- P410 P8

10 P810 P8

10 P810 P12

10 P1210 P4

10 P810 P12

10 P1210

5


- P410 P8

10 P810 P8

10 P810 P12

10 P1210 P4

10 P810 P12

10 P1210

Frost resistance Plain concrete

G50 G100 G150 - - G150 G150 - - - -

Reinforced concrete

G100 G150 G150 - - G150 G150 - - - -

6


G100 G150 G150 - - G150 G150 - - - -

Table 1-6. Grading classes Grading class in accordance to the cement content (Kg/m3) Consistency ≤ 300 300-450 > 450

T2 I (II)* II (III)* III T3 and T3/T4 I (II)* II (III)* III T4, T4/T5, T5 I I (II)* II (III)* * Recommended when the concrete does not have tendency of honeycombing Upper and lower limit of gradation are as follows (annex 5): Table 5.1. to 5.6 for aggregate size 0...7 mm; 0...16 mm; 0...20 mm; 0...31 mm; 0...40 mm; 0...71 mm. Source: NE 012-1999


18

Table 1-7. Upper and lower limits of gradation Table 7.1. Aggregates between 0...7 mm. Source: NE 012-1999

Cumulative percent passing by mass (%) Limits 0,2 1 3 7 Max. 12 40 70 100 Min. 3 25 54 95 Table 7.2. Aggregates between 0...16 mm. Source: NE 012-1999

Cumulative percent passing by mass (%) Grading class

Limits 0,2 1 3 7 16

Max. 15 45 65 85 100 I Min. 10 35 55 75 95

Max. 10 35 55 75 100 II Min. 5 25 45 65 95

Max. 5 25 45 65 100 III Min. 1 15 35 55 95 Table 7.3. Aggregates between 0...20 mm. Source: NE 012-1999

Cumulative percent passing by mass (%) Grading Class

Limits 0,2 1 3 (9) 7 (10) 20

Max. 15 40 60 80 100 I Min. 10 30 50 70 95

Max. 10 30 50 70 100 II Min. 5 20 40 60 95

Max. 5 20 40 60 100 III Min. 1 10 30 50 95 Table 7.4. Aggregates between 0...31 mm. Source: NE 012-1999

Cumulative percent passing by mass (%) Grading Class Limits 0,2 1 3 7 16 31

Max. 15 40 50 70 90 100 I Min. 10 30 40 60 80 95

Max. 10 30 40 60 80 100 II Min. 5 20 30 50 70 95

Max. 5 20 30 50 70 100 III Min. 1 10 20 40 60 95 Table 7.5. Aggregates between 0...40 mm. Source: NE 012-1999

Cumulative percent passing by mass (%) Grading Class

Limits 0,2 1 3 (5) 7 (10) 20 40

Max. 15 30 45 60 80 100 I Min. 10 20 35 50 70 95

Max. 10 25 35 50 70 100 II Min. 5 15 25 40 60 95

Max. 5 15 25 40 60 100 III Min. 1 5 15 30 50 95 Table 7.6. Aggregates between 0...71 mm. Source: NE 012-1999

Cumulative percent passing by mass (%) Limits 0,2 1 3 7 16 25 31 40 71

Max. 8 18 32 45 61 70 77 84 100 Min. 1 6 13 22 38 50 57 68 95

Table 1-8. Standard types of Portland cement 1. According to national standards (S.R.) The S.R. has defined five types of Portland cement, identified in the specification (NE 012-99) by the Roman numerals I to V. These types, discussed below serve to indicate variations in properties that is brought about by varying composition and fineness. These types are identical with the European norm ENV 197 they are as follows: Type I - (SR 388), this cement is intended for general concrete construction where special properties are not necessary. It is a "ordinary" Portland cement. Type I is less restricted in chemical composition than the other types; Type II - (SR 1500), this cement is intended for use where concrete may be exposed to moderate sulphate action or where no more than moderate liberation of heat is advisable;


19

Type III – (SR 3011), this cement is high-early-strength Portland cement it is called "rapid hardening." It is high in fineness. It develops good strength within one day, and is used where concrete must be placed in service as soon as possible (hydrotechnical cement); Type IV - this is called low heat cement. It is used where considerable thickness of concrete is required and temperature rise might be excessive, thus leading to excessive volume change and cracking. It is generally produced only for special, large projects. Type V - (SR 3011), this cement, which also is not always available, is for use severe high sulphate resistance is required. Air - entraining cement. - the norm adds "A" to its type numbers to indicate air-entraining cement. Various organic chemicals are added in amounts up to a few hundredths (by weight of cement) to entrain fine bubbles in the mix. The concrete containing by volume of these fine air bubbles has greatly increased resistance to scaling from frost action. The entrained air also produces a more workable mix. 2. Cement agreements 2.1. Other types of cements can be used, manufactured by the European norm ENV 197 special cements or manufactured by agreement. These will be used only when it is specified agreements certified by testing, by the manufacturers at a certified agreement institute, that will put the products to test. If the results are satisfactory a certificate is issued, and can then be used by the manufacturer. The certificates are widely recognized and can be used until such times, as the S.R. is prepared. 2.2. White and colored cements. According to S.R. 1055 and colored cements, according to S.P. Source: NE 012-1999 Table 1-9. Cement types according to Romanian standards (SR)

Admixture Type Sort SR % Type

Grade

1 2 3 4 5 6 Portland Cement (without admixtures)

CEM I Normal Portland cement (without admixtures) SR388 - - 32,5N;42.5N; 52.5N

32.5R;42.5R;52.5R Composite Cements (with admixtures)

CEM II A-M Portland cement composite SR

1500 6-20 Mixture of slag, ash, lime, pozzolan

CEM II A-S Portland cement with slag Granulated blast furnace

slag CEM

II A-V Portland cement with ash Pulverized fuel ash

CEM II A-P

Portland cement with natural pozzolan Natural pozzolan

CEM II A-L Portland cement with lime Lime

32,5N;42.5N;52.5N 32.5R;42.5R;52.5R

CEM II B-M Portland cement composite SR 1500 21-35 Mixture of slag, ash, lime,

pozzolan CEM II B-S Portland cement with slag Granulated blast furnace

slag CEM II B-P

Portland Cement with natural pozzolan Natural pozzolan

CEM II B-L Portland cement with lime Lime

32,5N; 42.5N 32.5R; 42.5R

CEM III A Blast furnace cement SR 1500 36-65 Granulated blast furnace slag 32,5N; 32,5R

CEMIV A Pozzolan cement SR 1500 11-35 Pozzolan and ash 32,5N; 42.5N;32.5R

CEM V A Composite cement SR 1500 18-30 Granulated blast furnace slag + ash Pozzolan 32.5N; 32.5R

Hydrotechnical cements H I Cement without mixture - - HII/A-S 6- 20

HII/B-S 21-35

HIII/A

Cement with slag SR 3011

36-65

Granulated blast furnace slag

32,5N;42,5N;52,5N


20

Sulfate resistant cements SRI Cement without admixture - -

SRII/A-S Cement with slag 6-20 Granulated blast furnace slag

SRII/A-P Pozzolan cement 6-20 Natural pozzolan

SRII/B-S Cement with slag 21-35 Granulated blast furnace slag

SRIII/A Cement with slag

SR 3011

36-65 Pulverized fuel ash

32,5N;42,5N;52,5N

Source: NE 012-1999 Table 1-10. Recommended types of cement used for concrete works in normal exposure conditions Item no.

Work conditions and/or member characteristics

Concrete grade

Type of concrete Recommended types of cement

Usable types of cement

0 1 2 3 4 5 C 4/5 … C 8/10

Plain (CEMIIIA, CEMIVA,CEMVA) 32,5 N CEM IIB - 32,5 N

(CEMIIIA, CEM IVA,CEM VA)32,5 N CEM IIA 32,5 N

C 12/15 … C 16/20

Reinforced CEM IIA - 32,5 N CEMIIB- 32,5(1)N; CEMIIB- 42,5(1)N; CEM I 32,5 N CEM IIA- 42,5 N

C 20/25 C 25/30 C 35/

Reinforced CEM I - 32,5 N CEM IIA - 32,5R; CEM IIA - 42,5N; CEM I - 42,5 N

C 30/37 C 40/ C 35/45 C 40/50

Reinforced (prestressed)

CEM I - 42,5 N CEM I -42,5A N

CEM I- 32,5(2)N; CEM I- 52,5N; CEM I 52,5A N

1

Members or constructions with thickness smaller than 1,5m produced in periods other that winter

C 45/55 C 50/60 C 60/70 C 70/80

High strength reinforcement (prestressed)

CEMI52,5N/ 52,5R; CEMI52,5AN/ 52,5AR

< C 12/15 C 12/15

Plain H III/A - 32,5 N H II/B-S; CEMII B-S 32,5N; CEM I A-S 32,5N

C 16/20 Reinforced H II/A - 32,5 N H I-32,5; HII/B-S32,5(1); CEMII A-S 32,5N

C 20/25 C 25/30 C 35/-

Reinforced H I - 32,5 N CEMII A-S 32,5N; H II/A-S32,5; CEM I 32,5N

C 30/37 C 40/- C 35/45 C 40/50


H I - 42,5 N H I-32,5(2); CEM I 42,5N; HII/A-S 42,5; H42,5/42,5 RA; CEMII A-S 42,5 N

2

Massive members or constructions with thickness equal or larger than 1,5m

C 50/60 C 60/70 C 70/85


H I - 52,5 N HII/A-S52,5N; H52,5/52,5-A N

Technical notes: 1. During winter conditions it is recommended to use, for members that have thickness over 1,5 m, cements with rapid setting time noted with R. 2. The setting for cement types CEM II B, II H, H II/B-S (that have a maximum amount of mixture of 35%), for reinforced concrete members will be made only with the approval of a specialist institute. Source: NE 012-1999


21

Table 1-11. Recommended types of cements for plain and reinforced concrete works exposed to sea water and severe freezing

Item no.

Work conditions and/or Member characteristics Concrete grade Type of

concrete Recommended types

of cement Usable types of cement

0 1 2 3 4 5 < C 16/20 Plain CEMIIA-32,5N/32,5R CEMI-32,5N/32,5R

C16/20-C35/ - Reinforced CEMI-32,5N/32,5R CEMIIA-32,5N/32,5R CEMI- 42,5AN; CEMI- 42,5N/42,5R

C30/37-C40/50 Reinforced CEMI-42,5N CEMI-42,5N/42,5R

CEMI-32,5N/32,5R; CEMI-52,5N/52,5R

1

Members or constructions with thickness smaller than 1,5m

C 45/55-C70/85 Reinforced CEMI-52,5AN CEMI-52,5N/52,5R

< C 16/20 Plain H II/A-S32,5 H I-32,5; II A-S32,5

C 16/20-C 35/ Reinforced CEMIII-32,5N CEMIII-42,5N

C 30/37-C40/50 Reinforced H I-42,5 H I-52,5; CEMI-52,5N

2

Massive members or constructions with thickness equal or larger that 1,5m C 45/55-C70/85 Reinforced H I-52,5

Source: NE 012-1999 Table 1-12. Recommended types of cements for plain and reinforced concrete works subjected to aggressive waters

Recommended types of cement Usable types of cement Item no.

Nature of aggressive

environment

Grade of aggressive Plain concrete Reinforced

concrete Plain concrete Reinforced concrete

0 1 2 3 4 5 6

1 Alkalis Mild CEMII A-S32,5R/42,5N

CEMII A-S32,5R/42,5N

CEMI 32,5N H I H II/A-S

CEMI 32,5N; H I; H II/A-S

Mild CEMII A-S 32,5N/42,5N

CEMII A-S 32,5R/42,5R

CEMI 32,5N; H I;H II/A-S32,5N/42,5N

CEMI 32,5N; H I;H II/A-S32,5N/42,5N 2

Carbon Severe very

severe CEMI 42,5N; CEMI 42,5R H I32,5N/42,5N SRI32,5N/42,5N

H I32,5N/42,5N; SR I32,5N/42,5N

Mild Moderate Moderate

CEMIII A;CEM IV A; CEMV A; CEMII B; CEMII A32,5N/42,5N

CEMII A-S32,5N/42,5N

H II A-S32,5N/42,5N

H II/A- S32,5N/42,5N

3

Sulfate Severe or very

sever (for all cases)

SR II/B-S32,5N/42,5NSR III/A32,5N/42,5N SR I SR II/A-S H II/B-S H III/A

H I32,5N/42,5N; H II/A-S32,5N/42,5N; CEMII A-S32,5N/42,5N

Mild H III/A32,5N/42,5N H II/B-S32,5N/42,5N

H II/A-S32,5N/42,5N

H A-S32,5N/42,5N

H A-S; H I; Sr I; SR II/A-S 4

Magnesium Severe or very

sever SR II/B-S32,5N/42,5NSR III/A32,5N/42,5N

SR II/A-S32,5N/42,5N

H A-S32,5N/42,5N H II/A-S32,5N/42,5N

H A-S; H II/A-S; H I; SR I

Mild H III A32,5N/42,5N H II/B-S32,5N/42,5N

H II/A-S32,5N/42,5N

H A-S32,5N/42,5N

H A-S; H I; SR I; SR II/A-S5

Nitrogen salts Severe or very

sever SR II/B-S 32,5N/42,5NSR III/A32,5N/42,5N

SR II/A-S32,5N/42,5N

H II/A-S32,5N/42,5N SR I; H I; H II/A-S

Mild H II/A-S32,5N/42,5N H I H A-S H II/A-S; II/A-S; SR I 6

Base Severe SR II/A-S32,5N/42,5N SR I H II/A-S H I;

H II/A-S


22

Table 1-13. Estimated mixing water requirement for various slumps Water (l/m3) of concrete indicated by consistency Concrete grade

T2 T3 T3/T4 T4 C 4/5 160 170 - - C 8/10...C 20/25 170 185 200 220 > C 25/30 185 200 215 230 Source: NE 012-1999. Technical notes: The values concerning the quantities of water required for mix specified in annex 13. are valid only if used with natural aggregates size 0...31 mm. They will be increasing or decreasing as follows: - decrees with 10% when using aggregates size 0...71 mm; - decrees with 5% when using aggregates size 0...40 mm; - decrees with 10-20% when using additives; - increase with 10% when using crushed stone; - increase with 20% when using aggregates size 0...7 mm; - increase with 10% when using aggregates size 0...16 mm; - increase with 5% when using aggregates size 0...20 mm. Table 1-14. Relative density

Type of material Density ( Kg/dm3 ) Siliceous (stream deposits) 2,7 Calcareous 2,3...2,7 Ceramic 2,7 Basalt 2,9 Cement 3,0 Table 1-15. Approximate volume of air-entrainment according to maximum size aggregates Maximum size of aggregates (mm)

7 10 16 20 31 40 71

Air-entrainment % 6 6 6 5 4,5 4 3,5 Table 1-16. Maximum values for w/c ratio after preliminary tests (grade II concrete homogeneity)

Cement grade Concrete grade 32,5 42,5 52,5

C 8/10 0,75 C 12/15 0,70 C 16/20 0,60 C 20/25 0,55 C 25/30 0,50 0,55 C 35/ - 0,45 0,50 C 30/37 0,40 0,47 C 40/ - 0,35 0,45 0,50 C 35/45 0,40 0,45 C 40/50 0,35 0,40 C 45/55 0,33 0,38 C 50/60 0,30 0,35 C 70/- Source: NE 012-1999 Technical notes: 1. The values for the table are valid for grade II homogeneity. For grade I, the values rise with 0,05 and for grade III they decrease with 0,05. 2. When using crushed stone the values form the table rise with 10%. 3. According to the environment conditions and exposure the w/c ratio, resulted form annex 2, should not be exceeded. 4. When the concrete is cured in steam rooms, according to the final decrease of strength, the w/c ratio values will be adopted as follows: for grade I of homogeneity see table and - for grade II of homogeneity, the proposed values for the table decreased by 0,05 (corresponding to grade III).


23

Table 1-17. Concrete strength at 28 days after preliminary tests for grade II homogeneity Characteristic strength fc preliminary (N/mm2)

Characteristic strength fc preliminary (N/mm2) Concrete grade

Cube Cylinder Concrete grade

Cube Cylinder C 8/10 18 14,5 C 40/- 51,5 41 C 12/15 23,5 19 C 45/35 56,5 45 C 16/20 29 23 C 50/40 62,5 50 C 20/25 36 29 C 55/45 68 54,5 C25/30 42 33,5 C 60/50 73 58,5 C 35/- 47 37,5 C 70/60 84,5 67,5 C 30/37 48 38,5 C 87/70 101 81 Technical notes: For grade I, respectively grade III of homogeneity, of the values required in the table, a certain value will be subtracted or added. Source: NE 012-1999 Table 1-18. Values that will be subtracted or added to the recommended values for grade II

Concrete grade (N/mm2) (Cube) (N/mm2) (Cylinder) C 10/8 - C 20/16 3 2,5 C 25/20 - C 37/30 4 3 C 40/- - C 55/45 5 4 C 60/50 - C 85/70 6 5 Table 1-19. Concrete mix design parameters Item Concrete parameters Basic requirements 1 Type of cement Concrete grade, Conditions of exposure, Characteristics of member 2 Type of additive Transport conditions, Placement, Characteristic required of concrete

(durability, grade), Characteristics of member (section reinforcement) 3 w/ c ratio Concrete grade, Homogeneity grade achieved at batching, Water

tightness, Conditions of exposure 4 Minimum content of cement Conditions of exposure 5 Workability Conditions of transport and placement, Form and dimensions of member,

Dense reinforcement 6 Maximum size aggregate Form and dimensions of member, Reinforcement, Conditions of transport

and placement 7 Water requirement Workability (consistency), Type of admixture 8 Aggregate grading Cement content, Consistency, Technology of concrete placement

REFERENCES 1-1 ACI Committee Report, Guide of Concrete 309R-96 ACI Manual of Concrete Practice 1998. Part 2. 1-2 Asian Concrete Model Cod, Part II – Materials and Construction, Level 1, 2001. 1-3 Carare T., Cartea Fierarului Betonist. Editura Tehnica Bucuresti, 1986. pag.158-186. 1-4 Cement & Concrete Association of Australia, The housing concrete handbook, 2000. 1-5 Crainic L., Reinforced Concrete. Technical University of Civil Engineering of Bucharest, 1993. pag. 4-

38. 1-6 Dabija F.E., Buildings II. Technical University of Civil Engineering of Bucharest, 1994. 1-7 Dean Y., Mitchell’s Building Series. Materials Technology. Pearson Education Ltd, 1999. 1-8 Ilinoiu G. Quality of Concrete. Study on Code NE 012-1999. Nr. 3, Bulletin AICPS (2001), pp. 114-120. 1-9 Ilinoiu G. Concrete durability. Journal Civil and Industrial Constructions. 2001, No. 24, pp. 36-37. 1-10 Ilinoiu G. Decision making modeling of concrete requirements. Dimensi Teknik Sipil, Indonesia.

Research Center of Petra Christian University. Vol. 3, no. 2, September 2001. 1-11 Ilinoiu G. Conceptual approach of repair and rehabilitation works of structural members. Journal Civil and

Industrial Constructions. 2001, No. 26, pp. 30-34. 1-12 Ilinoiu G. Structural and mixture characteristics of Portland cement. Journal Civil and Industrial

Constructions, 2002, No. 30, pp. 16-22. 1-13 Ilinoiu G. Concrete permeability. Journal Civil and Industrial Constructions. 2001, No. 31, pp.18-24. 1-14 Ilinoiu G. Concrete freeze-thaw. Journal Civil and Industrial Constructions, 2002, No. 33, pp.18-21. 1-15 Ilinoiu G., Criteria for measuring concrete conformity. Journal Civil and Industrial Constructions, IV, Nr.

41 May 2003, pp.14-20. 1-16 Ilinoiu G., Uncertainty modeling measurement of concrete quality. Journal Civil and Industrial

Constructions, IV, Nr. 44 August 2003, pp.16-21. 1-17 Ilinoiu G., Compliance criteria for concrete conformity. Journal AICPS, 2/2003, pp.49-55. 1-18 Ilinoiu G., Construction Engineering. Conspress, Bucharest 2003.


24

1-19 Ionescu I., Ispas T., Proprietăţile şi tehnologia betoanelor. Editura Tehnică, Bucureşti, 1997. 1-20 Neville A.M. Concrete properties. Fourth edition. Editura Tehnica, 2003. 1-21 Popa R., Popa E., Tehnologia lucrarilor de constructii. Prepararea betonului. ICB, 1986. 1-22 Popa R., Teodorescu M., Tehnologia lucrarilor de constructii. ICB, 1984. 1-23 Teodorescu M. Utilizarea cimenturilor o chestiune de professionalism. Antrepenorul 3/2003, pag. 20. 1-24 Teodorescu M. Utilizarea cimenturilor in constructii o chestiune de professionalism (II). Antrepenorul

4/2003, pag. 37-38. 1-25 Teodorescu M., Tsicura A., Ilinoiu G., Compozitia betonului. UTCB, 1997. 1-26 Teodorescu M., Tsicura A, Ilinoiu G., Îndrumator pentru examenul de licenta la disciplina “Tehnologia

lucrarilor de constructii” UTCB, 1998. 1-27 ENV 206, 1990. Concrete Performance, Production, Placing and Compliance Criteria. 1-28 STAS 1275-1988. Tests of concrete. Tests of hardened concrete. Determination of mechanical strengths. 1-29 STAS 9602-90. Reference Concrete. Specifications for manufacturing and testing. 1-30 NE 012-1999. Practice code for the execution of concrete, reinforced concrete and prestressed concrete

works, Part 1 – Concrete and reinforced concrete. 1-31 NE 13-2002. Practice code for the execution of prefabricated elements. 1-32 STAS 10107/0-1990. Calculul si alcatuirea elementelor structurale din beton, beton armat si beton

precomprmat. 1-33 STAS 3622-86. Cement concretes. Classification. 1-34 STAS 1759-88. Tests on concretes. Tests on fresh concrete. Determination of apparent density,

consistence fine aggregates content and setting time. 1-35 ISO 9812. Concrete consistency. Slump test. 1-36 STAS 2414-91. Tests on concrete. Determination of density, compactness, and porosity of hardened

concrete. 1-37 STAS 3519-76. Tests on concretes. Inspection of waterproofness. 1-38 ISO 7031. Tests on concrete watertightness. 1-39 STAS 5479-88. Tests on concrete. Tests on fresh concrete. Determination of air content. 1-40 STAS 2833-80. Tests on concrete. Determination of axial shrinkage of hardened concrete. 1-41 STAS 3518-89. Tests on concretes. Strength determination at frost-thawing. 1-42 SR EN 196-4/95. Methods of testing cement. Quantity determination of constituents 1-43 EN 196-2. Methods of testing cement. Chemical analysis of cement. 1-44 SR 6232-96. Cements, mineral admixtures and additives. Vocabulary. 1-45 SR 388-95. Portland cement. 1-46 SR 1500-96. Usual composite cements, type II, III, IV and V. 1-47 SR 3011-96. Limited hydration warmth cements and resistant to water damage with sulphates content. 1-48 SR 7055-96. White Portland Cement. 1-49 SR 227/2-98. Cements. Physical tests. Determination of grinding fineness. 1-50 SR EN 196/6-94. Methods of testing cement. Determination of grinding fineness. 1-51 SR 227/5- 96. Cements. Physical tests. Determination of hydration heat. 1-52 SR EN 196/3-97. Methods of testing cement. Determination of setting time and soundness. 1-53 SR 227/4-86. Cements. Physical tests. Setting time determination. 1-54 SR EN 196/1-95. Methods of testing cement. Determination of strength. 1-55 STAS 1275-1988. Tests of concrete. Tests of hardened concrete. Determination of mechanical strengths. 1-56 STAS 1667-76. Heavy aggregates for concrete and mortars with mineral binder. 1-57 STAS 2386-79. Lightweight mineral aggregates. General technical requirements for quality. 1-58 STAS 4606-80. Natural heavy weight aggregate for concrete and mortars with mineral binding material.

Testing method. 1-59 STAS 1667-76. Natural heavy weight aggregate for concrete and mortars with mineral binding material. 1-60 STAS 8625-90. Mixed plasticized additive for concretes. 1-61 STAS 8573-78. Waterproofing additive cement mortars. 1-62 STAS 790-84. Water for concretes and mortars. 1-63 STAS 1799-88. Concrete reinforced and prestressed concrete buildings. Type and frequency checks of

materials and concrete quality used for civil engineering execution. 1-64 STAS 6657/3-89. Concrete, reinforced concrete and prestressed concrete elements – procedures,

instrumentation and devices for characteristic geometry checks. 1-65 STAS 9602-90. Reference Concrete. Specifications for manufacturing and testing.


25

CHAPTER 2. RATE OF CONCRETE PLACEMENT ROUGH ESTIMATE

2.1. GENERAL CONSIDERATIONS The rate of concrete placement (pour) depends on a multitude of factors that influence the process, such as: - concrete characteristics (i.e. w/c ratio, consistency, workability etc.); - structural member characteristics (i.e. dimensions); - site organization (i.e. type of equipment used to prepare, transport, distribute and compact

the concrete, labor/ crews); - type of distributing equipment:

• when using a concrete pump, because it normally delivers concrete continuously, only the capacity of the pump need be considered in the calculation of the rate of pour;

• when using a crane with buckets, the rate of pour depends on the total time that it takes for one cycle of the crane to pick up a bucket, unload it and return it to the ground.

- type of concreting procedure adopted (i.e. concreting in predetermined lifts or whole heights of members);

- environmental conditions (i.e. humidity, temperature), etc.

2.2. EXAMPLE 1 Calculate the rate of concrete placement, rough estimate, for a section of a wall (wall

height 2,62 m, wall thickness 250 mm and wall length 30,5m), of a high-rise building, located at 16,5 m from ground level, using a tower crane and a concrete bucket with the capacity of 1 m3. Crane characteristics: rate of travel of 30 m/min up, 25 m/min rate of travel down, pickup time 20 sec dump time is 3 min. (Andres C., Smith R., 1998, 2003) Cycle time calculation:

Time to travel up min/30

5,16m

m = 0,55 min

Time to travel down min/25

5,16m

m = 0,66 min

Pickup time ss

6020 = 0,33 min

Dump time 3,00 min Total: 4,54 min = 0,076 hr Rate of concrete delivery in m3/hr:

R = V/t (m3/hr) = hr

m076,01 3

= 13,16 m3/hr

Rate of pour calculations: Volume of concrete to be poured:

V = H x l x L = 2,62 x1000250 x 30,5 = 19,98 m3

Time required to pour 19,98 m3 of concrete:

t = RV =

16,1398,19 = 1,52 hr

Rate of pour in m3/hr:

r = t

H wall

= 52,162,2 = 1,72 m/hr

2.3. EXAMPLE 2 Calculate the rate of concrete placement, rough estimate, for a section of a wall located

on the ground floor, using a concrete pump with the rate of delivery of 25 m3/hr (product specifications). Pour conditions: wall height 2,62 m, wall thickness 350 mm and wall length 10,30m. (Andres C., Smith R., 1998, 2003)

Volume of concrete to be poured: V = H x l x L = 2,62 x1000350 x 10,30 = 9,45m3


26

Time required to pour 9,45 m3 of concrete: t = RV =

2545,9 = 0,38 hr

Rate of pour in m3/hr: r = t

H wall

= 38,062,2 = 6,98 m/hr

REFERENCES 2-1 Andres C., Smith R. Principles and Practices of Heavy Construction. Prentice Hall, USA, 1998. 2-2 Andres C., Smith R. Principles and Practices of Commercial Construction. Prentice Hall, USA, 2003. 2-3 Ilinoiu G., Construction Engineering. Conspress, Bucharest 2003. 2-4 La Londe W., Janes M., Concrete Engineering handbook. McGraw-Hill Company Inc., 1961 2-5 Peurifoy R., Oberlender G., Formwork for concrete structures. McGraw-Hill, 1996. 2-6 APA. The Engineering Wood Association, 1999. Concrete forming. Design and Construction Guide.


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CHAPTER 3. CONCRETE FORMWORK DESIGN 3.1. GENERAL CONSIDERATIONS

If concrete is to be poured, in place-monolithically, on the job site some means of support, known as formwork, is necessary to shape, to position it precisely (level and location) and to retain it until it sets. In other words, it is a temporary “mould” into which fresh concrete and reinforcement are placed to form a particular reinforced concrete element with a predetermined strength.

3.2. MODULAR PLYWOOD FORMWORK

Plywood is a sheathing product made of several wood veneers with their grain lying (normal to one another) at right angles and firmly glued together under pressure, producing a panel that has uniform properties in both directions, an advantage regarding increased bending, shear, and deflection properties.

The usual format consists of framed panels on a timber studwork principle with a plywood-facing sheet screwed to the studs so that it can be easily removed and reversed to obtain the maximum number of uses. The modular plywood formwork consists of standard framed panels tied together over their backs with horizontal members called walings. The wales provide resistance to the horizontal force of wet concrete, supporting the studs and facilitating panel alignment. The wales are usually double square pipes (40 x 40 x 3,5; 45 x 45 x 4 or 55 x 55 x 4 mm). They are usually doubled so to allow the placing of tension ties, without any supplementary works regarding drilling of wales. Figure 3-1. Typical plywood panel Caption: 1. Plywood sheathing; 2. Batten (Stud); 3. Brace; 4. Transverse frame: e = 8; 15 mm, d = 92; 85 mm, c = 48 mm, i = 68 mm, f = 38 mm. Source: Popa R., 1978.

Table 3-1. Panel nominal dimensions Size Components Type of

panel Length (mm) Width (mm) No. of studs No. of traverse frames No. of braces Thickness of panel

P1 2400 300 2 2 3 P2 2400 400 3 2 6 P3 2400 600 3 2 6 P4 1200 300 2 2 1 P5 1200 400 3 2 2 P6 1200 600 3 2 2 P7 600 300 2 2 - P8 600 400 3 2 -

100 mm


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Figure 3-2 (a). Plywood panel formwork Caption: 1. Plywood sheathing; 2. Wooden wedges; 3. Wale; 4. Plate washer; 5. Bolt/Nut - Latch; 6. Tie rod; 7. Pipe spacer; 8. Plastic cone; 9. Shoe; 10. Clamp; 11. Wedge; 12. Concrete kicker. Source: Popa R., Teodorescu M., 1978.

Figure 3-2 (b). a,b,c and

d- panel accessories

Caption: a. PVC pipe spacer; b. Plastic cone; c. Latch; d. Clamp A standard procedure for site formwork assembly is as follows:

- Forms shall conform to the shape and dimensions shown on the drawings and shall be accurately set to line and grade. All sheathing in contact with concrete surfaces shall be sized to uniform thickness and free from wane, warp, splits, loose knots or other defects which will prevent obtaining a smooth, tight form.

- Forms shall be erected one side of the wall formwork, ensuring its correct alignment, plumbing, and/or strutting.

- Forms shall be tightened by means of slotted wedge that passes through the lower end of the slot. Joints in the lining shall be filled with patching plaster or other plastic filler. Lining material may be re-used if it is in satisfactory condition, well cleaned and re-oiled


29

- Insertion and positioning of steel reinforcement cage before the formwork for the other side is erected and fixed.

- Correct spacing of forms at specified distance from one another by using plastic spacer tubes in which ties are inserted.

- Positioning of horizontal members (wales) to increase the overall rigidity of the formwork panels and to align them.

- The spacing of wales varies form minimum at the bottom of the pour to a maximum uniform spacing at the top. The spacing depending on the maximum allowable span of the studs.

- Insertion of ties between wales, covering them at the outside with plate washers to ensure that the loads are evenly distributed over the wales.

- The size and spacing of the ties depend on the load on the wales. - Forms for walls, etc., shall have large cleanout openings at their lowest points, which

shall not be closed until just before placing concrete. All forms shall be thoroughly cleaned and soaked with water immediately before filling.

General requirements for slab forming design: 1. The panels preferred for use will be those that have the maximum size 600 x 2400 mm. 2. On every direction of the formwork design a panel removal (strike off) joint will be

positioned with the size of 50 or 100 mm in accordance to the modular span of the slab. 3. The positioning of removal joints will be continuous, and will be placed towards the

middle of the formwork paneling. 4. Removal joints can be adopted with the thickness of 150 or 200 mm, when these are the

only solutions to complete the formwork. 5. On a slab formwork if the standard size panels cannot close the entire area, a filler panel

can be used (square or rectangular wooden lumber plank) with the maximum size of 500 x 500 mm.

6. The filler panel is recommended to be positioned at the intersection of the removal joints. 7. All slabs will be formed in two variants, respecting the main directions of form

disposition. From the two the economical one will be chosen in regard of the minimum number of joists that are used. In case of equality of joists between the two variants, the one with the minimum number of panel forms will be chosen

8. Every panel will be supported at two sides by two joists. These will not be positioned on adjoining sides or a side in console.

9. The joists will be positioned in accordance with a main direction of form placement for every slab.

10. A minimum number of reuses for panels should be assured. We are not allowed to cut or deteriorate them (10 reuses).

General requirements for wall forming design: 1. The panels preferred for use will be those that have the maximum size 600 x 2400 mm. 2. On the vertical face of the wall formwork a panel removal (strike off) joint will be

positioned with the size of 50 or 100 mm in accordance to the modular span of the wall. 3. The removal joints will be continuous on the height of the wall, and will be put one in

front of the other in the thickness of the wall, and will be positioned at the middle of the formwork paneling.

4. The forming paneling should begin from the interior of the building; more precisely form the intersection of walls, towards the middle.

5. A minimum number of reuses for panels should be assured. We are not allowed to cut or deteriorate them.


30

3.3. SHORING MEMBERS Shoring members support formwork and their contents, bearing loads and limiting

their deflections. They can be divided into two major categories according to type and shape of concrete

member that will be formed: a. Horizontal shores (telescopic joists) range from small units 1,8 m, to large members 9,0 m, used to carry much heavier loads.

Telescopic joists known also as centers present the following characteristics: - They are manufactured from wood or high-tensile steel. - Load bearing capacity according to span. - Possibility of precambering to compensate any deflections when loaded. - Requirement of propping and bracing. - Lightweight so that it can be carried by one-two workers.

Figure 3-3.

Typical steel telescopic joists.

Source: Chudley R., 1999.

Table 3-2. Allowable spans “d” (m) between joists in accordance with span and load

Telescopic joist 1,8…3,0 m Source: Teodorescu M.; Tsicura A.; Ilinoiu G., 1997 Span of joist “D” in accordance with “d” distance between joists Load of

panel and concrete N/m2

2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000

d (m) 0.5 2.97 2.82 2.69 2.58 2.39 2.34 2.31 2.24 2.18 2.17 2.06 2.01 1.96 1.92 1.80 0.6 2.77 2.62 2.50 2.39 2.30 2.21 2.14 2.07 2.01 1.96 1.91 1.86 1.82 0.7 2.60 2.46 2.34 2.24 2.15 2.07 2.00 1.94 1.88 1.83 0.8 2.46 2.33 2.21 2.12 2.03 1.96 1.89 1.83 0.9 2.34 2.21 2.10 2.01 1.93 1.86 1.0 2.24 2.12 2.01 1.92 1.84 1.1 2.15 2.03 1.93 1.84 1.2 2.07 1.96 1.86


31

Telescopic joist 3,0…5,0 m Source: Teodorescu M.; Tsicura A.; Ilinoiu G., 1997 d (m) 0.5 5.00 4.93 4.68 4.47 4.29 4.13 3.98 3.85 3.74 3.63 3.53 3.44 3.36 3.28 3.21 0.6 4.83 4.55 4.32 4.13 3.96 3.80 3.67 3.55 3.44 3.34 3.25 3.17 3.09 3.02 0.7 4.51 4.25 4.04 3.85 3.69 3.55 3.42 3.31 3.21 3.11 3.03 0.8 4.23 4.01 3.80 3.63 3.47 3.34 3.22 3.11 3.02 0.9 4.04 3.80 3.61 3.44 3.29 3.17 3.05 1.0 3.85 3.63 3.44 3.28 3.14 3.02 1.1 3.69 3.47 3.29 3.14 1.2 3.55 3.34 3.16

Telescopic joist 3,6…6,0 m Source: Teodorescu M.; Tsicura A.; Ilinoiu G., 1997 d (m) 0.5 6.00 6.00 5.80 5.54 5.31 5.11 4.92 4.76 4.62 4.48 4.36 4.25 4.14 4.05 3.96 0.6 5.98 5.64 5.35 5.11 4.89 4.70 4.53 4.38 4.25 4.12 4.01 3.91 3.81 3.72 3.64 0.7 5.59 5.27 4.99 4.76 4.56 4.38 4.23 4.08 3.96 3.84 3.73 3.64 0.8 5.27 4.96 4.70 4.48 4.29 4.12 3.97 3.84 3.72 3.61 0.9 4.99 4.70 4.46 4.24 4.07 3.91 3.76 3.64 1.0 4.76 4.48 4.25 4.05 3.87 3.72 1.1 4.56 4.29 4.07 3.87 3.71 1.2 4.38 4.12 3.91 3.72 b. Vertical shores (also known as props) are those that support the horizontal shores (joists) from a firm base below. They may be manufactured of wood or steel, with various shapes, depending on the particular scope. Vertical wood shores may be single wood posts, with wedges to adjust the height, double

wood posts, two-piece adjustable posts, or T head shores. Vertical metal shores may be adjustable pipe shores or shores made up of prefabricated

steel tubing. Scaffold-type shoring, is usually assembled into towers by combining a number of units into a single shoring structure.

Figure 3-4. Typical adjustable steel pipe shore (prop) Source: Teodorescu M.; Tsicura A.; Ilinoiu G., 1997.


32

Table 3-3. Allowable axial load “P” (daN) on shore in accordance with length. Item name Steel shore

PE 3100R Steel shore PE 5100R

Steel shore with

spatial base

PES 3100R

Steel shore with

spatial base

PES 5100R

Light steel telescopic shore PU 3100

Light steel telescopic shore PU 1200R

Hmax (mm) 3100 5100 3100 5100 3100 1220 Hmin (mm) 1700 3100 1700 3100 1700 232

min 20000 18000 2000 18000 6000 3000 Load (N) max 45000 45000 45000 45000 12000 45000

3.4. FORMWORK PRINCIPLES The principles behind good formwork are based on the same basic frame theories used

in the design and construction of structural frames. Formwork must be able to withstand construction forces that, in many respects, can be more severe than those experienced by the completed structure. It is imperative that each component of the formwork be erected according to the formwork drawings to ensure that all construction loads are safely supported.

Although formwork is temporary in nature, the methods used in building formwork must adhere to the code specifications that apply to the particular material being used. Each component of the form must be able to support its load from two points of view: (1) strength, based on the physical properties of the material used; (2) serviceability, the ability of the selected sections to resist the anticipated loads without exceeding deflection limits.

3.4.1. FORMWORK LOADS The basic consideration in form design is strength-the forms ability to support, without

excessive deflections, all loads, and forces imposed during construction. Two types of problems arise in formwork design:

Horizontal forms support gravity loads e.g. mass of the concrete and reinforcement, construction crew and equipment, weight of the formwork itself and the vibrating effect of the concrete compaction.

Vertical forms must primarily resist lateral pressures due to a particular height of plastic concrete (e.g. static load from lateral pressures due to a particular height of plastic concrete, dynamic load from lateral pressures due to impact of falling concrete during placement, and wind forces on wall forms. The individual form panels and members may be limited to bending, shear, bearing, or

deflection and all four should be checked against the allowable values prescribed by norms and specifications.

Two types of loads are considered in the design calculations: vertical loads and horizontal loads.

3.4.2. FORMWORK PRESSURES The pressure exerted by concrete on formwork is determined primarily by the

following factors: rate of concrete placement, concrete temperature, weight of concrete, method of concrete vibration and depth of placement.

The lateral pressure exerted by plastic concrete on vertical formwork is rather complex in nature and is affected by several factors. The freshly placed concrete initially acts as a liquid, exerting fluid or hydrostatic pressure against the vertical form.

Because hydrostatic pressure at any point in a liquid is the result of the weight of the fluid above, the density of the concrete mix influences the magnitude of the force acting on the form. Nevertheless, because fresh concrete is a composite material rather than a true


33

liquid, the laws of hydrostatic pressure apply only approximately and only before the concrete begins to set.

The rate of placement also affects lateral pressure. The greater the height to which concrete is placed while the whole mass remains in the liquid stage, the greater the lateral pressure at the bottom of the form.

The temperatures of concrete and atmosphere affect the pressure because they affect the setting time. When these temperatures are low, greater heights can be placed before the concrete at the bottom begins to stiffen, and greater lateral pressures are therefore built up.

Vibration increases lateral pressures because the concrete is consolidated and acts as a fluid for the full depth of vibration. This may cause increases of up to 20% in pressures over those incurred by spading. Other factors that influence lateral pressure include the consistency or fluidity of the mix, the maximum aggregate size and the amount and location of reinforcement.

Norm C11-1974 specifies the following loads for formwork design: (1) VERTICAL LOADS, include: a). Weight of the formwork itself and the scaffold: - lumber in panels 7500 N/m3 - lumber in shoring elements 6000 N/m3 - plywood 8500 N/m3 b) Weight of fresh concrete: - normal weight (heavy) concrete: plain 24000 N/m3

reinforced 25000 N/m3 - lightweight concrete 7000– 19000 N/m3 c). Uniform distributed load of runways for concrete transport and impact loads of the crowding of crewmen: - panel design 2500 N/m2 - horizontal shoring (joists) of panels 1500 N/m2 - vertical shoring elements (props, columns etc.) 1000 N/m2 d). Concentrated load form weight of work crews and transport equipment: - one crew member that carries loads 1300 N - wheel barrow concrete transport 2800 N e) Load from the vibrating effect of the concrete compaction: 1200 N/m2 (2) HORIZONTAL LOADS, include: f) Static load from lateral pressures due to a particular height of plastic concrete (placed and compacted) according to the rate of placement (see Figure 3-5) on the panels surface.

Figure 3-5. Lateral pressure on wall form according to rate of concrete placement Source: Teodorescu M., Tsicura A, and Ilinoiu G., 1998.


34

Two factors that affect the maximum effective horizontal pressure are seen to be: rate of rise of the concrete in the forms and rate of setting (loss of fluidity).

The first depends on the size of form or forms being filled vs. the rate at which the concrete is placed. The second depends on a number of factors, of which the most significant is the temperature. The time of setting for concrete according with NE 012-99 is when the temperature of concrete is 10o…30o C is 35…40 min and for t < 10o C is 50…70 min according to the grade of cement used (32,5 or 42,5).

The effect of pressure in compacting the lower fluid layers by forcing out mixing water (bleeding) has led to the belief that for very rapid rates of rise there is a maximum pressure which cannot be exceeded. It will usually be more economical to control the rate of rise that to try to provide form strength to resist such high pressures.

The rate of placement the relation between the height of the form H and the time period needed for the casting of the whole element. The rate of pour is expressed in meters of concrete poured per hour.

The hydrostatic lateral pressure is given by the following equation: p = ρ x H Where: p – lateral pressure [N/m2] ρb – unit weight of fresh concrete [N/m2] H – height of plastic concrete [m] Table 3-4. Characteristics of concrete pressure on formwork

Characteristics λ1 λ2 λ3 λ4 ≤ 1 0.55 2 0.65 3 0.75 4 0.85 6 0.90 8 0.95

Rate of pour (m/hour)

≥ 10 1.00 ≤ 1 0.85 1…4 0.95 5…9 1.00 10…15 1.05

Workability of concrete,

slump (cm) ≥ 15 1.10 ≤ 15 0.90 16…54 0.95 Minimum section

of element (cm) ≥ 55 1.00 ≤ 5 1.00 6…24 0.95 Concrete

temperature (oC) ≥ 25 0.90

Source: Teodorescu M., Tsicura A, and Ilinoiu G., 1998. The position of the maximum pressure is determined with the following equation:

xHh 1p λ= Where: λ1 – has the value according to table 3-4.

The value of the maximum pressure Pmax is determined with the following equation:

b4321max xHxxxxP ρλλλλ= (N/m2) Where: H – the height of the poured concrete (m);

ρb – density of fresh concrete (kg/m3). The minimum pressure Pinf is determined with the following equation:

maxinf xPP α= (N/m2) Where: α - has the value according to table 3-5.


35

Table 3-5. Coefficient α according to rate of concrete placement. Rate of placement

(m/hour) < 1 2 3 4 6 8 ≥10

α 0 0.25 0.45 0.70 0.80 0.90 1.00 Source: Teodorescu M., Tsicura A, and Ilinoiu G., 1998. g) Dynamic load from lateral pressures due to impact of falling concrete during placement: - for a capacity of the transport equipment: 0,2 m3 ...........................2000 N/m2

0,2...0,7 m3....................4000 N/m2 0,7 m3............................6000 N/m2

- for placement with chutes and hoppers: 2000 N/m2 - for placement with concrete pumps: 6000 N/m2 h) Wind forces on wall forms that will be taken into account only for bracings, scaffolds, and centers. 7000 N/m2

For the design of the size and deflections of component elements of the formwork, the loads will be taken into account differently, according to the table 3-6. Table 3-6. Combination of loads according to member

Loads Item name Strength Deflection Slab and arch forms and horizontal props (beams) a + b + c + d a + b Vertical props for floors a + b + c a + b Column forms with the maximum face of 30 cm and walls of maximum 10 cm thickness f + g f

Column forms and walls with bigger values f f Lateral faces of forms for beams and arches f f Bottom of beams a + b + e a + b Centers and scaffolds < 6 m a + b + c (e) a + b Centers and scaffolds > 6 m a + b + c (e) + h a + b Source: Teodorescu M., Tsicura A, and Ilinoiu G., 1998 and C 11-74

The design of formwork components will be made according to the following characteristics: type of material used, nature of the load, number of reuses, moisture conditions and deflection limitations.

3.4.3. FORM MATERIAL PROPERTIES

Materials used for forms include lumber, plywood, plastics, steel, aluminum etc. Additional materials that are used include: nails, bolts, screws, ties, anchors etc.

Properties of form material - Allowable bending stress of lumber (σa) 12 N/mm2 - Allowable bending stress of plywood (σa)

- When the face grain is parallel to the span 13 N/mm2 - When the face grain is perpendicular to the span 5 N/mm2

- Allowable bending stress of steel (σa) 210 N/mm2 - Modulus of elasticity (E) lumber 10.000 N/mm2 plywood 7.000 N/mm2 steel 210.000 N/mm2 - Allowable bending deflection limitations for the various modular panels are usually:

(L maximum clear span)/300 – for concrete surfaces exposed to view; (L maximum clear span)/200 – for concrete surfaces with finishing.

- Allowable tolerances for panels: - for length and width of panel + 2 mm; - for thickness of panel - 5 mm; - for length of diagonals of panel ± 5 mm.


36

3.5. WALL, SLAB FORMWORK AND SHORING SYSTEMS DESIGN Figure 3-6. Symbols for cross section of rectangular beam Table 3-7. Nomenclature of symbols

List of symbols U.M. Meaning X-X or Y-Y Neutral axes: A line through a member (beam or column)

under flexural stress, on which there is neither tension nor compression. It is the middepth of the member and perpendicular to the loading of the member,

B [mm] Width of beam face on which load or force is applied H [mm] Depth or height of beam face parallel to the direction inn

which the load or force is applied δ [mm] Plywood thickness h slab [mm] Thickness of slab M [Nmm] Bending moment I = bh3/12 (for a rectangular beam)

[mm4] Moment of inertia of the cross section of a beam is the sum of the products of each if its elementary areas times the square of the distance from the neutral axes of the section to the areas, multiplied by the square of their distance from the neutral axes.

y [mm] Distance from neutral axes to most distant fiber of beam σe [N/mm2] Applied bending stress σa [N/mm2] Allowable bending design stress W = I/y = bh2/6 (for a rectangular beam)

[mm3] Section modulus of the cross-section is the moment of inertia of the section divided by the distance from the neutral axes to the most distant, fiber of the section.

E [N/mm2] Modulus of elasticity P [N] Concentrated load do to work crews and transport

equipment q [Nml] Uniformly distributed load pre unit length (ml)

3.5.1. SLAB FORMWORK AND SHORING SYSTEM DESIGN

Formwork must be checked to ensure that they withstand bending and shear and that deflection will not exceed 1.5 mm.

INITIAL DESIGN DATA Thickness of slab h slab, Clear span of slab. Story height H story.

b

d Y-Y y

X-X

b

d y


37

EVALUATION OF LOADS

a. Weight of 8 (15) mm panel sheathing: δpanel x 8500 = ….. N/m2 b. Weight of fresh concrete (h slab): h slab x 25000 = .…. N/m2 c. Uniform distributed load of runways for concrete transport and impact loads of the crowding of crewmembers: ….. N/m2 d. Concentrated load weight of work crews and transport equipment: ….. N e. Load from the vibrating effect of the concrete consolidation; ….. N/m2 Note 1: The loads on plywood are usually considered as being uniformly distributed over the entire surface of the plywood. The concentrated load “d” can by transformed in a uniform distributed load, by dividing it to the span “l”. Note 2: This design recommends three basic span conditions for computing the uniform load capacity of plywood panels. The span may be single span, two-spans or three –span according to the panel’s width.

PLYWOOD PANEL DESIGN

Recommended thickness of plywood (δpanel) is 8 or 15 mm. When calculating the allowable pressure of concrete on plywood as limited by the

allowable unit stress deflection of the plywood, use the clear span between supports.

a. For 30 cm width panel: q (daN/m)

l = 25.2 cm q l/2 q l/2

Reactions for a simple beam with a uniformly distributed load Verification for bending stress: The calculation is made for a width of b=1m.

q = (a + b + c) x 1.00 + d/l (N/ml) Where: l = span between supports (25.2 cm) The maximum bending moment that will occur at the center of the beam, will be calculated as follows:

M = ql2/8 The applied bending stress must not exceed the allowable bending design stress:

ae σσ ≤ Where: eσ = applied bending stress;

aσ = allowable bending design stress.

ae WM

IyM σσ ≤==

M = q x l2/8; W= b x h2/6

h = 8 or 15 mm

Verification for deflection: The calculation is made for a width of b=1m.

q = (a + b) x 1.00 m (N/ml) For a rectangular beam subjected to bending the applied deflection f can be calculated form the following equation:

ExIqxlxf e

4

3845

=

The applied deflection must not exceed the allowable design deflection:

ae ff ≤ Where: ef = applied deflection; af = allowable design deflection.

2003845 4 lf

ExIqxlxf ae =≤=

I = bxh3/12 (mm4) h = 8 or 15 mm E = 7000 (N/mm2)

b. For 60 cm width panel: q (daN/m)

l = 27.6 cm l = 27.6 cm

Reactions for a simple beam with a uniformly distributed load spanning over three or more equally spaced supports


38

Verification for bending stress: The calculation is made for a width of b=1m.

q = (a + b + c) x 1.00 + d/l (N/ml) Where: l = span between supports (27,6 cm) The maximum bending moment that will occur at the center of the beam, will be calculated as follows:

M = ql2/10 The applied bending stress must not

exceed the allowable bending design stress: ae σσ ≤

Where: eσ = applied bending stress;

aσ = allowable bending design stress.

ae WM

IyM σσ ≤==

M = q x l2/10; W= b x h2/6

h = 8 or 15 mm

Verification for deflection: The calculation is made for a width of b=1m.

q = (a + b) x 1.00 m (N/ml) For a rectangular beam subjected to bending the applied deflection f can be calculated form the following equation:

ExIqxlxf e

4

005.0=

The applied deflection must not exceed the allowable design deflection:

ae ff ≤ Where: ef = applied deflection; af = allowable design deflection.

200005.0

4 lfExIqxlxf ae =≤=

I = bxh3/12 (mm4) h = 8 or 15 mm E = 7000 (N/mm2)

HORIZONTAL STEEL TELESCOPIC JOIST DESIGN

H

q

15

15 Joist

Shore (prop)

Figure 3-7. Typical view of joist and prop

Requirement: Spacing of joists under paneling “d” (m). Loads: q = a + b (N/m2) From table 3-2, according to the type of joist used, the load “q” and the span of the joist “D” the spacing “d” of joists under paneling is given. Technical note: If the value “d” is not a common measure of the standard panel length, the joists will be placed at equidistance, but not more than “dmax” for the table.

BATTEN (STUD) DESIGN The design will be made in the most least favorable situation, this will be the design of the central stud of the 60 cm width plywood panel. Loads: For verification for bending stress: q = (a + b + c) x l.00 + d/l (N/ml) For verification of deflection: q = (a + b) x 1.00 m (N/ml)


39

a. For panel with L = 1.20 m and spacing between joists d = 1.20 m

q (daN/m)

L = 1.20 m

P

h=85 or 92

b=48 Verification for bending stress:

ax

e WM

σσ ≤= = 12 N/mm2

48

2 PxLqxLM += ;

65,8x8,4

6bxhW

22

==

h = thickness of stud 85 or 92 mm

Verification for deflection:

2003845 4 lf

ExIqxlxf ae =≤=

12bxhI

3

= (mm4)

b=48 mm, h = 85 mm E = 10000 (N/mm2)

b. For panel with L = 2.40 m and spacing between joists d = 1.20 m

q (daN/m)

L = 1.20 m L = 1.20 m

P P

Verification for bending stress:

ae WM σσ ≤= = 12 N/mm2

4203,0

8

2 PxLxqxLM += ;

65,8x8,4

6bxhW

22

==



200005,0


12bxhI

3

= (mm4)

b=48 mm, h = 85 mm E = 10000 (N/mm2)

c. For panel with L = 2.40 m and spacing between joists d < 1.20 m

q (daN/m)P P P

L L L



4175,0

8

2 PxLxqxLM += ;

65,8x8,4

6bxhW

22

==



200007,0


12bxhI

3

= (cm4)

b=48 mm, h = 85 mm E = 10000 (N/mm2)


40

STEEL PIPE SHORE DESIGN

H

P

15

15

Figure 3-8. Schematic view of prop (shore) The design will be made for the most loaded shore.

( )2DxdxcbaP ++= (daN)

Where: d – spacing of joists support under the paneling (m); D – span of telescopic steel joist (m).

The steel pipe shore will be chosen according to the equation: ( ) ( )

( ) PHH

HHxPPPP story

a ≥−

−−−=

minmax

minmax

max (daN)

3.5.2. WALL AND COLUMN FORMWORK DESIGN

INITIAL DESIGN DATA Member dimensions. Technology of concrete placement. Rate of concrete placement. Temperature of concrete. Workability of concrete (consistency). Story height H story. Thickness of slab hslab.

Technical note: The design will be made for a wall with a thickness grater that 10 cm and respectively a column with the edge grater that 30 cm.

LOADS f) Static load from lateral pressures due to a particular height of plastic concrete (placed and compacted) according to the rate of placement on the panel’s surface.

Figure 3-9. Pressure distribution of lateral face of panel

b4321max xHxxxxP ρλλλλ= (N/m2)

maxinf xPP α= (N/m2) xHh 1p λ=

Where: λ1 – coefficient according to work conditions. H – the height of the poured concrete (level) (m). ρb – unit weight of fresh concrete (2400 kg/m3). α - coefficient according to rate of pour. Technical note: The design will be made for a plywood sheet of 30 respectively 60 cm width. If in the design just one of the above panels is used then the design will be made for that one.

The design will be made for a width of panel b = 1,00 m The load is considered uniformly distributed, with the value of:

m00,1x2

pp00,1fxq infmax ⎟

⎠

⎞⎜⎝

⎛ +== (N/ml)


41

PLYWOOD SHEATHING DESIGN

Verification of plywood panel a. For 30 cm width panel:

q (daN/m)

l = 25.2 cm Verification for bending stress:


M = q x l2/8; W = b x h2/6 b= 100 cm h = 8 or 15 mm


2003845 4 lf

ExIqxlxf ae =≤=

12bxhI

3

= (mm4)

b=1.00m, h = 15 mm E = 7000 (N/mm2)

b. For 60 cm width panel: q (daN/m)

l = 27.6 cm l = 27.6 cm


ae WM

σσ ≤= =13 N/mm2

M = q x l2/10; W = b x h2/6 h = 15 mm


200005.0


12bxhI

3

= (mm4);

b=1.00m, h = 8 or 15 mm E = 7000 (N/mm2)

A

pmax B

C

D 40 cm

D3

D2

D1

15 cm pmin

Figure 3-10. Pressure of concrete on wall form

STUD DESIGN (DISTANCES BETWEEN WALES)

The design will be made in the most least favorable situation, that is the design of the central stud of the 60 cm width plywood panel. The load is uniform distributed, with the value:

m276,0x2

pp276,0fxq infmax ⎟

⎠

⎞⎜⎝

⎛ +== N/ml


ae σσ ≤ ⇒ aWqxD σ≤

8/2

⇒q

xWxD aσ10

=

σa = 12 (N/mm2) W = b x h2 / 6; b = 48 mm; h = 85 mm


200007.0

4 DExI

qxDxff ae ≤⇒≤ ⇒ 3xq4,1

ExID =

12bxhI

3

= (mm4)

b=1.0 m; h = 15 mm. E = 10.000 (N/mm2)

The values will be chosen as follows: D1=Dmax, like the minimum value for “D” calculated for the verification of resistance and deformation, but not more that 60 cm. The values for D2 and D3 will be 40% and respectively 60% of the remaining distance B-D (where B-D = H story – D1 – 0,15 – 0,40 cm).


42

SPACING BETWEEN WALES (DISTANCES BETWEEN TIES)

q (daN/ml)

d d 60 cm

Where: d – distance between ties; D – distances between wales (vertical). Figure 3-11. Spacing between ties A

pmax B

C

D 40 cm

D3

D2

D1

15 cm pmin

pD

pC

pB

pA

The wall formwork design will be made according to the lateral pressure of fresh

concrete; this may use the calculation to determine the spacing of wales. It will be assumed that the first tie will be as close to the bottom of the form as is practical, within 150…200 mm, and that the top tie will be at or near the top.

The values for pA, pB, pC (N/m2) will be calculated according to the known values pmax and pinf (N/ml). The wale most stressed will be calculated (wale most near to the highest pressure point – point B), with the following equations:

( )2

1D15,0xpq AA+

= (N/ml)

( )2

2D1Dxpq BB+

= (N/ml)

( )2

3D2Dxpq CC+

= (N/ml)

( )4

qxq2qq CBA ++

= (N/ml)


aae Wqxd σσσ ≤⇒≤

10/2

⇒ q

xWxd aσ10

= Example of wale (square shape

pipe): 40 x 40 x 3,5 (W=5,73x103 mm3; I=11,50 x104 mm4) 45 x 45 x 4 (W=8,25 x103 mm3; I=18,60 x104 mm4)

55 x 55 x 4 (W=12.9 x103 mm3; I=35,60 x104 mm4) Verification of deflection:

200007.0

4 dExI

qxdxff ae ≤⇒≤ ⇒ 34,1 xqExId = Where: σ = 210 (N/mm2)

E = 210.000 (N/mm2) Technical note: dmax will be chosen as the minimum value resulted for both the verification of resistance and deflection. The distance d ≤ dmax, will be adopted according to the formwork design plan, knowing that the tie will be put only between panels.

TIE DESIGN Only the most loaded tie will be calculated, that is the one placed nearest to point B

(see figure). The tensile stress on the tie is: T = q x d (N) Where: d- correct distance between ties, according to formwork design plan.

aa R

TA = ; Ra = 2100 (N/mm2)

The diameter of the tie will be chosen according to neca

ea AA ≥


43

3.6. EXAMPLE WORKING DRAWINGS Typical Floor Level Plan Sc.: 1:100


44

Wall Formwork Plan Sc.: 1:100

P3

P3

P1P1

P1

P2P2

P3

P1

P3P2P2P1P1

P2

P1P1

P2

P3P3

P3

P3

P3

P1

P1P1P1

P1

P1P1

P3P3

P2P3 P3

P3P3P3

P3

P3

P3

P1

P1P1 P1

P1P1

P3

P1P1P1

P1

P1P1

P1 P1 P1 P1

P1P1P1P1

P3

P3

P3

P1

P3

P3

P3

P1P2

P1P1

P1

P2P2

P3

P1

P2P2

P3

P1P2

P1

P1P1

P2

P3P3

P2

P3P3

P3

P3

P2 P2

P2P2

P3

P3

P3

P3

P3

P3

P1

P1

P1P1

P1

P1P1

P1P1P1

P1P1P1

P1P1P1P1

P1 P1 P1 P1

P3

P3

P3

P3

P3

P3

P1 P1P2


45

Slab Formwork Plan Sc.: 1:100

P3

P6

P8

P8P7

P3

P6

P3 P3 P3

P6 P6 P6

P2

P2P1

P2 P2

P5 P5

P3 P3 P3 P3

P6P6P6P6

P2

P2P1P7

P8

P8

P2

P5

P8


46

Typical Transverse Cross Section of Shored and Formed Level Sc.: 1:100

Caption: 1. Plywood panel, 2. Strike off joint, 3. Steel joist, 4. Brace, 5. Steel prop, 6. Longitudinal cross bracing, 7. Transverse cross bracing, 8. Upper horizontal brace, 9. Lower horizontal brace, 10. Prop base plate, 11. Plate washer, 12. Steel wale, 13. Tie rod, 14. Spacer, 15. Nut, 16. Reinforced concrete wall, 17. Slab, 18. Beam.


47

Typical Longitudinal Cross Section of Shored and Formed Level Sc.: 1:100

Caption: 1. Reinforced slab. 2. Plywood panel, 3. Reinforced wall, 4. Spacer, 5. Tie rod, 6. Wale, 7. Plate washer, 8. Nut, 9. Lumber plank, 10. Prop base plate, 11. Steel pipe shore, 12. Steel Joist, 13. Transverse cross bracing, 14. Longitudinal cross bracing, 15. Upper horizontal bracing, 16. Lower horizontal bracing, 17. Prop head, 18. Brace.


48

Details of Beam Formwork

a. Girder form details. 1. Girder; 2. Panel end support; 3. Stringer; 4. Prop; 5. Ledger; 6. Brace; 7. Prop; 8. Shore head; 9. Panel sheathing. Source: Andres C., 1998.

b. Spandrel beam form details. 1. Stud; 2. Tie back; 3. Plywood sheet; 4. Ledger; 5. Joist; 6. Slab for sheathing; 7. Tie; 8. Wales; 9. Brace; 10. Ledger; 11. Shore head; 12. Double shores. Source: Andres C., 1998.

c. Spandrel beam form details. 1. Concrete slab, 2. Decking, 3. Joist, 4. Ledger, 5. Stud, 6. Kicker, 7. T head, 8. Brace, 9. Scab, 10. Wale, 11. Brace, 12. Stud, 13. Brace, 14. Prop. Source: Peurifoy R., 1996.


49

3.7. STEEL MODULAR PANEL FORMWORK 3.7.1. GENERAL CONSIDERATIONS

Modular steel panel forms provide several ways to form columns of various shapes and sizes; they can be combined to form square or rectangular columns. Generally modular steel panels provide a fast and more accurate column form than job-built forms.

The length of the steel column form is determined be subtracting the thickness of the bottom of the girder form that the column is to carry from the column height indicated on the plans or in the column schedule. Once the column forms are in place, they must be plumbed, braced, and made ready to support the ends of the girder and the beam forms that will be built to them.

3.7.2. MODULAR STEEL COLUMN FORMWORK The steel form consists of four panels, of various widths and lengths that are fastened

together at each corner. Yokes, wedge bolts, clips and clamps are used to secure the corners of the forms.

When positioning the yokes it will be assumed that the first one will be at the bottom of the form, and that the top yoke will be at top.

Steel column forms as shown in Figures 3-10, being available for maximum forming height of 7,20 m and maximum edge of column 95 cm; 2,0 mm steel sheathing produces the finishing of concrete. This type of formwork is available in three variants according to the area formed, respectively Type A – 150 m2, Type B – 300 m2 and Type C – 300 m2.

Figure 3-12. Typical assembly of steel modular panels Source: IPC, 1977.


50

Table 3-8. Modular steel formwork components Item Symbol l

Width (mm)

L Length (mm)

H Height (mm)

Q Weight

(kg) Panel P1 1190 23,52

Panel P2 590 12,44

Panel P3 290 6,92

Panel P4

70 500

100 3,75

H

L l

o o o o o o o o o o o o o

o o o o o o o o o o o o

5 0

Short lower yoke * Cb1 750 5 3,39

Long lower yoke ** Cb2 1250 5 5,05

Short middle yoke * Cm1 750 10 3,39

Long middle yoke ** Cm2 1250 10 10,12

Short upper yoke * Cs1 750 5 3,39

Long upper yoke ** Cs2

70

1250 5 5,05

Clips CL1 0,28

Clips CL2 0,28

Clamps K

0,30

Inclined braces S1

S2

min. 1700

(3000) max. 3000

(5550)

11,10

Scaffold type E75 1000

(1500) 1000

(1500) nx 750

Note 1: *Short yokes will always be used forming columns with widths of max. 500 mm. **Long yokes will always be used for forming columns with widths of 500 to 950 mm.

Note 2: When the edge of the column is smaller than 500 mm, one single width panel will be used for forming that particular face of the column;

When the edge of the column is smaller than 950 mm, two panels by width will be used for forming that particular face of the column.


51

Figure 3-13. Typical E75

scaffold, view and assembly phases a, b and c

Source: Plesca A., 1998.

Figure 3-14. Assembly phases of

steel modular column formwork a to g

Source: IPC, 1977.


52

3.7.3. EXAMPLE OF WORKING DRAWING

Steel Modular Column Formwork Erection Plan (Elevation and Cross section)

P1

P1

P1 - 500 x 1190

P1

P1P1

P1

REFERENCES 3-1 Andres C., Smith R.: Principles and Practices of Heavy Construction. Prentice Hall, USA, 1998. 3-2 Andres C., Smith R., Principles and Practices of Commercial Construction. Prentice Hall, USA, 2003. 3-3 APA. The Engineering Wood Association, 1999. Concrete forming. Design and Construction Guide. 3-4 Chudley R., Building site works, substructure and plant. Longman Scientific and Technical, 1988. 3-5 Chudley R., Advanced Construction Technology. Pearson Education Ltd., England. 1999. 3-6 Ilinoiu G., Construction Engineering. Conspress, Bucharest 2003. 3-7 IPC. Catalog Cofraj metallic stâlpi CMS. 1977. 3-8 Technical Specification. IPC, Steel Modular Column Formwork, 1977. 3-9 Peurifoy R., Oberlender G., Formwork for concrete structures. McGraw-Hill, 1996. 3-10 Plesca A. Manualul dulgherului. Editura Tehnica, 1998. 3-11 Popa R., Teodorescu M.: Cofraje modulate de lemn. ICB, Bucuresti, 1978. 3-12 Teodorescu M., Tsicura A, Ilinoiu G., Îndrumator pentru examenul de licenta la disciplina “Tehnologia

lucrarilor de constructii” UTCB, 1998. 3-13 C11-74. Instructiuni tehnice privind alcatuirea si folosirea in constructii a panourilor din placaj.


53

CHAPTER 4. CONCRETE MATURITY 4.1. GENERAL CONSIDERATIONS REGARDING CONCRETE MATURITY

Poor curing practices affect the desirable properties of concrete. Proper curing of concrete is essential to obtain maximum durability, especially if the concrete is exposed to severe environmental conditions where the surface will be subjected to excessive wear, aggressive solutions, or severe exposure conditions (such as cyclic freezing and thawing). Likewise, proper curing is necessary to assure that design strengths are attained.

In-situ concrete curing is perhaps the most critical factor in the concrete construction process. Sufficient curing is essential if the concrete is to perform its intended function over the life of the structure. The key word here is “sufficient,” because contractors are sensitive to the time value of money. Excessive curing time can add to the construction cost of a project and cause unnecessary delay.

4.2. MATURITY INDEX METHOD The standard method of evaluating the concrete strength in cast concrete members is

to test specimens for compressive strengths. The main disadvantages are that the results are not obtained immediately; the concrete in specimens may differ from that in the actual structure because of different curing and compaction conditions; and that the strength properties of concrete specimens depend on its size and shape. An alternative is using the concrete maturity index determination that provides a very important link in the chain of testing and evaluating in-situ cast concrete.

The maturity method accounts for the effects of temperature on strength development. It is necessary to understand the temperature sensitivity of the rate of strength development of different concrete mixtures in order to use this method to account for the effects of temperature on the minimum required curing duration.

The maturity method is a viable method for determining curing durations under different temperature conditions. Several studies have shown that the maturity method can be used to estimate strength gain during concrete curing.

The advantage of the studied maturity method is the fact that the strength determination does not involve destructive stresses, and because it can be used to estimate the rate of hardening and strength development of concrete in the early stages in the scope of determining: Stripping of forms and the application of load as construction proceeds. A minimum temperature to prevent freezing during winter concreting operations (to

assure a minimum rate of hydration so that the properties may develop over a reasonably short time).

Minimum concrete strength required for handling, transport and storage of precast members.

Minimum concrete strength required for prestressing force release for inducing precompression.

4.3. MINIMUM DURATION FOR CONCRETE STRENGTH ATTAINMENT The minimum duration for concrete strength attainment is influenced primarily by the

mix design, environmental, exposure and curing conditions. The minimum duration of curing is based on the concrete reaching a specified

maturity. Once the specified value is defined, empirical relationships between time, cement type, water-cement ratio, temperature and concrete grade are used to estimate the minimum curing duration. Cementitious addition materials have slower reaction of hydration rates than Portland cement, needing longer curing periods (Table 4-1 and 4-2).


54

Table 4-1 Recommended critical cold weather maturity level for concrete (Mk) Critical maturity index for concrete (MK) [h O C], (at +20 O C), for different w/c ratio

w/c ratio 0,4 0,5 0,6 0,7

CEM II A-S 32.5 850 1 100 1 400 1 620 CEM I 32.5 750 1 000 1 270 1 500

Where: MK - critical maturity index necessary for obtaining a quality concrete before its complete freezing [hro C]; w/c ratio – water : cement ratio; CEM II A - S 32.5 – Composite Portland cement

CEM I 32.5 - Ordinary Portland cement Table 4-2. Recommended striking off maturity level for concrete (Mβ)

Striking off maturity level of concrete (Mβ) [hOC], (at +20 O C), for β= [%] Hardening level β (%) 10 20 30 40 50 60 70 80 90 CEM II A - S 32,5 600 880 1290 1880 2760 4050 5930 8700 12700 CEMI 32.5 520 740 1150 1690 2510 3720 5520 8200 12100 Where: Mβ - maturity index necessary for striking off formwork [hro C];

β - rate of concrete hardening, percentage value according to the concrete grade.

Figure 4-1 indicates the concrete thermal regime. It represents two characteristic variants, by discreet separation of the time variable in its steps, Figure 4-1.a., shows the standard concrete temperature which is varying on a straight line from θi-1 value at the beginning to θi at the end and the second, Figure 4-1.b., for a concrete that has its freeze temperature artificially lowered through additives.

Time [hr]

t i-1

+30

+20

+10

0

Temperature θ [oC]

θ i-1

t I t I+1 -10

+40

θ i

θ I+1

t k t n

Mθ i

Time [hr]

t i-1

+30

+20

+10

0

Temperature θ [oC]

θ i-1

t I t I+1

-10

+40

θ i

θ I+1

t k

t n

(a) Normal Concrete (b) With Additives

Figure 4-1. Temperature variation of concrete for different ages and freezing temperatures For both graphs, the lower datum temperature was considered as –10oC and the upper

datum temperature as +30oC.

4.4. CRITICAL CONCRETE HARDENING LEVEL The deviation from the “normal step of temperature”, is defined by two limits. The

minimum temperature θbmin = +1 oC, that represents positive values, and the maximum temperature θbmax = +30 oC, that is obtained according to the cement composition.

Beyond these limits, a series of physical and chemical phenomena appear. These phenomena have disadvantageous effects on the concrete structure and implicit on the final strengths that will remain inferiors to those obtained in normal environmental conditions.


55

If a minimum concrete strength is developed between these limits known as critical rate of hardening (βK), in cold weather, the concrete will not be damaged, for this value being defined the critical maturity index MK.

The attainment of the critical rate of hardening (βK), depends on certain factors such as concrete mix design, type of cement, voids volume, water quantity and entrapped air do to compaction.

4.5. RATE OF CONCRETE HARDENING IN ACCORDANCE WITH ITS THERMAL HISTORY

The concept of maturity establishes correlations between the rate of hardening, β, and the maturity index, Mβ, at normal temperature θij, but especially for different cement types used in the concrete mix.

The maturity index Mβ [hoC], is defined by the content area between the concrete temperature variation curve and the –10 oC ordinate (datum temperature - theoretical adopted value for which the chemical reactions stop), on the tβ duration (hr).

The method accuracy regarding the correlation of determination, β - Mβ for the usual cements, highlight the fact that the method accuracy decreases if the concrete temperature has great variations in comparison with the environmental temperature θ. However, the accuracy is improved by the application of kθ method, which establishes correlations between the concrete hardening level at different temperature steps and the maturity index Mθ.

θθβθ KMM =

Kθi - rate constant involving the maturity index assessed at θ'i and that assessed at the standard laboratory temperature of +20 O C; Mθ

β is the maturity strike off index at a specific temperature θ (see table 4-3).

The concrete maturity index, for time ti will be calculated as follows: ( ) ii tKM θθ 10' += [hroC]

Considering a straight-line variation between θi-1 and θi temperatures, for θ’i:

21' ii

iθθ

θ+

= − [oC]

The maturity index shall be estimated using the relationships:

( )∑∑==

≥+==n

i

Nk

Nii

n

iii lyMrespectiveMktkMM

11

' 10' βθθθ θ [hroC]

Where: MNβ and MN

k are the required maturity index needed for striking off formwork respectively critical cold weather index.

Example of concrete maturity achieved in normal environmental conditions (+20 oC, 28 days): ( ) 201600,1*24*28*102028 =+=M [hroC]

4.6. CONCRETE CURING MINIMUM DURATION Concrete elements should normally be cured for a period not less than that given in

Table 4-4. Depending on the type of cement, the environmental conditions and the temperature of the concrete, the appropriate period is taken from Table 4-1 and 4-2 or calculated from the last column of that table. During this period, no part of the surface should fall below a temperature of 5 °C.

The surface temperature depends upon several factors, including the size and shape of the section, the cement content of the concrete, the insulation provided by the formwork or other covering, the temperature of the concrete at the time of placing and the temperature and


56

movement of the surrounding air. If not measured or calculated, the surface temperature should be assumed equal to the temperature of the surrounding air.

The maturity function, with a datum temperature of -10 °C, is used to establish the minimum duration of the curing period for surface temperatures between 1 °C and 30 ºC. Thus the numbers columns of Table 4-3 represent temperature-time factors in ºC×h. These temperature-time factors depend on the cementitious system and the exposure conditions.

The duration of protection against freezing may be calculated from the maturity of the concrete. Alternately protection is no longer needed if a compressive strength of 5 N/mm2 is obtained. Table 4-3. Values of coefficient kθi of equivalency

Values of coefficient kθi of equivalency for the maturity level assessed at θ'i temperature and that assessed at the standard temperature of +20 oC

1...5 6...10 11...15 16...20 21...25 26...30 θi Kθi θi Kθi θi Kθi θi Kθi θi Kθi θi Kθi 1 0,270 6 0,800 11 0,912 16 0,968 21 1,020 26 1,136 2 0,420 7 0,840 12 0,924 17 0,976 22 1,040 27 1,172 3 0,560 8 0,868 13 0,936 18 0,984 23 1,060 28 1,208 4 0,660 9 0,884 14 0,948 19 0,992 24 1,080 29 1,244 5 0,760 10 0,900 15 0,960 20 1,000 25 1,100 30 1,280

A special attention should be given, after form removal, to the structural member because it will bear the whole design load. The following values of hardening level (β) are recommended for striking off:

2,5 N/mm2 – for the lateral parts of the formwork; 70% of the concrete grade for the bottom formwork parts of slabs and beams, with

spans ≤ 6,0 m; 85% of the concrete class for the bottom formwork parts of slabs and beams, with a

span > 6,0 m. The safety props will be removed when the following values of concrete strength

percentage is achieved: 95 % for reinforced concrete members with spans ≤ 6,00 m; 112 % for reinforced concrete members with spans between 6,0.... 12,0 m; 115 % for reinforced concrete members with spans > 12,0 m.

Table 4-4. Striking time for concrete formwork Minimum duration before striking forms for given surfaces according to temperature of

concrete Temperature of concrete

Type of concrete surfaces Cement type

10…+5oC +5…+15oC +15…+30oC CEMIIA–S32,5 2 days 1 day 1 day Vertical surfaces to columns,

walls and beams CEMI 32,5 2 days 1 ½ days 1 day CEMIIA–S32,5 5 days 5 days 3 days Soffits to slabs and beams

smaller than 6 m length CEMI 32,5 6 days 5 days 4 days CEMIIA–S32,5 6 days 5 days 4 days Soffits to slabs and beams

grater than 6 m length CEMI 32,5 10 days 8 days 6 days CEMIIA–S32,5 10 days 8 days 5 days Props to beams and slabs

smaller than 6 m length CEMI 32,5 18 days 14 days 9 days CEMIIA–S32,5 14 days 11 days 7 days Props to beams and slabs

between 6…12 m length CEMI32,5 21 days 18 days 12 days CEMIIA–S32,5 28 days 21 days 14 days Props to beams and slabs

grater than 12 m length CEMI 32,5 36 days 28 days 18 days


57

4.7. EXAMPLE Assume a reinforced concrete slab, with the span of 6 m, concrete grade C 15/12 batched with the following: cement type CEM II A – S 32,5, water: cement ratio w/c=0,50.

Calculate: (a). after how many days the slab formwork can be removed, and (b) if the concrete will freeze, in the second day after casting, in the possibility of a cold weather front arriving. The temperature variation of the concrete in this time interval is as follows:

Day Time of temperature reading [h] Temperature [OC] 7 12

12 19 18 20

1

21 18 8 12

15 21 2

20 18 7 11

14 18 3

18 17 8 12

15 20 4 21 17

Table 4-5. Control chart for calculating the concrete maturity index Concrete temperature

(oC) ii xkM θθ [hroC] Day

no. Time of

temperature reading Measured θi Mean θ’i

kθi Time interval between

readings ti [h]

Simple Cumulus

- - - - - 7 o’clock 12 15.5 0.964 5 123 123

12 19 19.5 0.996 6 176 299

18 20 19 0.992 3 86 385

1

21 18 15 0.960 11 264 649

8 12 16.5 0.972 7 180 829

15 21 19.5 0.996 5 147 976

2

20 18 14.5 0.954 11 257 1233

7 11 14.5 0.954 7 164 1397

14 18 17.5 0.980 4 108 1505

3

18 17 14.5 0.954 14 327 1832

8 12 16.0 0.968 7 176 2008

4

15 20 18.5 0.988 6 169 2177


58

21 17

∑=

=n

1ik tt = 86 hours

a. The maturity index required for formwork removal will be attained at 2008 [hOC]. According to cement type (II A – S 32,5) and the desired hardening level β = 40 %, results the maturity index of minimum Mβ = 1880 hoC. The maturity index corresponding to the hardening degree level β = 40 %, will be achieved in the 4 th day, and it will have the following value: Mef = 2008 [hoC] > Mβ = 1880 [hoC]. b. In the second day after casting, in the possibility of a cold weather front arriving, the concrete will not be deteriorated do to freezing, because Mef = 1233 [hoC] > Mk = 1100 [hoC].

REFERENCES 4-1 Ilinoiu G., Testing hardened concrete using the maturity concept. Dimensi Teknik Sipil, Indonesia.

Research Center of Petra Christian University. Vol. 5, no. 1, March 2003. 4-2 Ilinoiu G., Noi concepte in studiul si cercetarea maturităţii betonului. Construcţii Civile şi Industriale.

Anul V, Nr. 49, Ianuarie - Februarie 2004, pag. 9-11. 4-3 Ilinoiu G., Budan Ctin, Potorac B., Concrete maturity index determination. SELC XV Piatra Neamt

October 2003, pp. 8-12. 4-4 Ilinoiu G., Construction Engineering. Conspress, Bucharest 2003. 4-5 Fiorato A. E., Burg R. G. and Gaynor R. D., Effects of Conditioning on Measured Compressive Strength

of Concrete Cores. Concrete Technology Today. No. 3, Vol. 21, 2000; 4-6 Meeks K.W., Carino N.J., Curing of High-Performance Concrete: Report of the State-of-the-Art. NISTIR

6295, U.S. Dept. of Commerce, March 1999. 4-7 Swenson E.G., Durability of concrete under winter conditions. CBD-116. 4-8 Teodorescu, M., Ilinoiu G., Concrete maturity. Technical University of Civil Engineering of Bucharest,

1997. 4-9 Trelea A. Mathematics modeling of the concrete thermal regime, Proceedings International Symposium

15-16 Oct. Cluj-Napoca Romania. Vol. 1. 1993. 4-10 ENV 206, 1990., Concrete Performance, Production, Placing and Compliance Criteria. European

Committee for Standardization. 4-11 C 16-1984. Normativ pentru realizarea pe timp friguros a lucrărilor de construcţii şi a instalaţiilor aferente; 4-12 STAS 1275-1988. Tests of concrete. Tests of hardened concrete. Determination of mechanical strengths. 4-13 STAS 9602-90. Reference Concrete. Specifications for manufacturing and testing. 4-14 U 6-78. Normativ privind lucrul utilajelor de constructii pe timp friguros. 4-15 NE 012-1999. Practice code for the execution of concrete, reinforced concrete and prestressed concrete

works, Part 1 – Concrete and reinforced concrete.


59

CHAPTER 5. ESTIMATES This chapter establishes uniform guidance in describing methods, procedures, and

formats for the preparation of construction cost estimates construction projects from planning phases through modification estimates during concrete construction.

5.1. GENERAL CONSIDERATIONS Estimating is a process that begins in the early stages of a project and ends when the

project is turned over to the owner. Each estimate should be developed as accurately as possible, in as much detail as can

be assumed, and be based upon the best information available regarding actual costs of construction. This objective is to be maintained so that, at all stages of the project design and during construction, the cost estimate will in all aspects represent the "fair and reasonable" cost to the owner guiding him in design decisions.

5.2. TYPES OF ESTIMATES The main types of estimating concrete structures are: rough estimating and detailed

estimating divided into estimating during design stage and estimating during construction stage.

5.2.1. ROUGH ESTIMATING During the design stage, very little is known about the actual project, to estimate such

projects only on descriptions and conceptual sketches rough estimating is used. The variants of this type of estimating are (LaLonde, Janes):

1. Square meter of floor-area estimates / Cubic meter of volume estimates. 2. Average-component estimates. 3. Use-unit estimates.

It should be mentioned that rough estimating is usually used in the conceptual stages of a project, when very little is known about specifics. The advantage is that it can be calculated very quickly, the disadvantage being its accuracy of plus or minus 15 to 20%. 1. Square meter of floor-area method / Cubic meter of volume method, calculates the number of square meters (cubic meters) of floor area or building volumes after which and a unit cost per square meter (cubic meters) is used as a multiplying factor. This unit cost may be for the entire structure including the basement and roof or only for those floors that are essentially similar, after which a separate unit price would be assigned to the nonconforming areas. When deciding on what this unit price shall be, the estimator has several alternatives: Take into consideration the actual as-built cost figures for past projects. With a notation

that new factors should be anticipated such as: used of new technologies, marketplace demand on material and labor, quantities of materials, bargaining agreements, level of quality and even requirements for completion.

Take into consideration cost data published or announced for other like structures. Some publications such as the “Norme de Consum Orientative pe Articole de Deviz pentru Lucrări de Construcţii” (Item tabulations of material consumption and labor costs for construction works) publish cost indices and recent percentage figures on price trends. But sometime they can be misleading, or incomplete and should be studied with considerable care, do to the fact that costs can change rapidly during periods of inflation and deflation.

2. Average-component method, calculates unit costs for sections of work, such as bays or even spans, after which the calculated cost is applied to every other similar section. The advantage of this method is the fact that it allows economies do to construction repetitious


60

and increased volume of works. This method is usually used for buildings, apartments, office buildings, warehouses, and the flat-slab type of construction. 3. Use-unit method is applicable to stadiums, theatres, apartment houses, and office buildings. This method considers that groups of seats, single rooms, or entire suites of rooms are repetitive. Which means that when taking into consideration two identical structures as function, but different as size, the cost per room/suite/seat/ bed for a hospital/ pupil for a school etc., for the larger structure will be for example with 20 per cent or 25 per cent more.

Very often rough estimates are made before detailed plans or specifications have been prepared. The greatest use of such rough estimates should be primarily as guide figures to be given to an owner or to an architect to help them decide whether a job should be commenced. These rough estimates will also indicate to them the necessity of trimming certain items to fit the available money or show the possibility of including additional features which had previously been ruled out as being beyond their financial limit. Furthermore, as a rough estimate will also help pick up any gross errors in a detailed estimate.

5.2.2. DETAILED ESTIMATE Once all design documents are completed, companies interested in performing the

work price the project. This estimate is the most detailed and the most important. The main five major divisions are incorporated in a detailed estimate for a reinforced-

concrete structure, are: formwork, concrete, reinforcing steel, finishing and administration (LaLonde, Janes). Table 5-1. Estimate schedule

Unit cost Total cost % of Sub-Total Item no. Item Dimensions No. Quantity Unit

Labor Material Labor Material 1.0. Foundations 2.0. Substructure 3.0. Superstructure 3.1 Columns m3 3.2 Bearing

walls

3.3 Slabs 3.4 Beams 4.0. Exterior closure 5.0. Roofing 6.0. Interior construction 7.0. Conveying 8.0. Mechanical 9.0. Electrical 10.0. Special construction 11.0. Site work

Sub-total Contractor fees

The quantity take-off is made from the plans either by tallying dimensions (preferable) or by direct scaling. The most common mistakes to be avoided are the repetition of something previously included and the failure to multiply identical elements by the correct total number of such elements.


61

When starting an estimate all plans and technical specifications must be carefully studied so that the estimator is thoroughly familiar with the particular job. At all times, the estimator must keep a mental image of the completed structure so that he may visualize structural details, materials used or reused, for maximum economy.

The entries in tabulated of each item (Table 5-1) will be properly identified so that changes of addition or deletion may be easily accomplished at a later date. Checking for completeness will also be facilitated. All dimensions should be listed in a uniform sequence such as length, width, and height in all entries so that no time is devoted to attempted recognition of what certain figures mean.

BASICS FOR PREPARATION OF ESTIMATES Estimate preparation will be made in a normal sequence of events as works

commence. Construction cost estimates consist of:

1. Descriptions of work elements to be accomplished (tasks). 2. A quantity of work required for each task. 3. A cost for each task quantity (price sources). A unit cost for each task is developed to increase the accuracy of the estimating

procedure and should provide a reference comparison to historic experience. Degree of Detail. All cost estimates will be prepared on the basis of calculated

quantities and unit prices that are commensurate with the degree of detail of the design known or assumed. This is accomplished by separating construction into its incremental parts. These parts are commonly referred to as construction tasks and are the line-by-line listings of every estimate. Each task is then defined and priced as accurately as possible. Tasks are seldom spelled out in the contract documents, but are necessary for evaluating the requirements and developing their cost.

At the most detailed level, each task is usually related to and performed by a crew. The cost engineer develops the task description by defining the type of effort or item to be constructed. Task descriptions should be as complete and accurate as possible to lend credibility to the estimate and aid in later review and analysis.

Quantities. The quantity “take-off” is an important part of the cost estimate. It must be as accurate as possible, and should be based on all available engineering and design data.

After the scope has been analyzed and broken down into the construction tasks, each task must be quantified prior to pricing. Equal emphasis should be placed on both accurate quantity calculation and accurate pricing. Quantities should be shown in standard units of measure and should be consistent with design units (kg, m, m2, m3, t).

The detail to which the quantities are prepared for each task is dependent on the level of design detail. Quantity calculations beyond design details are often necessary to determine a reasonable price to complete the overall scope of work for the cost estimate.

Formwork is usually estimated by assigning a unit price per square meter of contact area of forms against concrete. The unit price may be such that only the material is involved and the erection is covered separately, or it may include the actual cost of purchasing the material, fabrication of forms, cost of erection, bracing, staging, nails, bolts, ties, wires, oiling for release and stripping.

In arriving at the final figure, it must be kept in mind that reuse of forms is feasible in most cases. A good proportion of the lumber, plywood etc. may still be reused and will have a marketable value.

Concrete. Dividing the work into items, such as: foundations, walls, columns and beams will help you conveniently estimate the concrete. In addition, it is well to list the different items in each division in the approximate order in which they will be constructed.


62

Each different mixture of concrete will have a different cost per cubic meter, making it desirable to keep each strength under a separate heading. The cost per cubic meter may be determined by requesting bids from the various supply sources.

The cubic meter method usually estimates concrete. Normally, no deductions are made for holes or inserts unless the cross-sectional area of the material to be deducted is a substantial figure.

Reinforcing Steel. If the structural design is complete and all details of bends, dimensions, and hooks are shown, then estimates are made on that basis. Reinforcing steel is priced per kilogram or ton of steel. The take off sheet must show the total number of linear meters of each bar size and its type, description, and location the structure. It must clearly distinguish among straight and bent bars and spirals.

The unit cost will include the freight costs of shipping, storage on the job, manner of bundling, length, order of use (so as to keep storage coats down), cost of wire brushing, costs of cutting, bending, and placing of rods and tying at every intersection, finally positioning, and testing of selected samples to ensure correct supplying by the mill.

5.3. EXAMPLE OF PROJECT ESTIMATES 5.3.1. ESTIMATE QUANTITY OF MATERIALS, LABOR AND COST FOR

CONCRETE, REINFORCEMENT AND FORMWORK

B1 B2

B1 B2

B3

B4

3,80 4,05

8,60

15 a

30

30

5,25

2,25

8,20 30

25 2525

hslab

30

30

INITIAL DATA: H level = 2.85 m

h slab = 12 cm h beam = 30 cm

BUILT AREA S built area = ∑ level

builtA

S slabbuiltarea = 3,8 x 2,25 + 4,05 x 2,25 + 3,8 x 5,25 + 4,05 x 5,25 =

= 8,55 + 9,11 + 19,95 + 21,26 = 58,87 m2

S slabbuiltarea =58,87 m2


63

S wallbuiltarea = 2 x 8,20 x 0,25 + 4 x 0,15 x 0,20 + 8,10 x 0,30 + 0,30 x 0,25 =

= 4,1 + 0,12 + 2,43 + 0,075 = 6,725 m2. S wallbuiltarea =6,725 m2

S columnbuiltarea = 2 x 0,40 x 0,20 = 0,16 m2

S columnbuiltarea = 0,16 m2

S beambuiltarea = 2 x 3,8 x 0,3 + 2x 4,05 x 0,3 + 1,95 x 0,25 + 4,95 x 0,25 == 6,44 m2

S beambuiltarea = 6,44 m2

S built area = ∑ nivel.constrA = S slab

builtarea + S wallbuiltarea + S column

builtarea + S beambuiltarea =

= 58,87 mp + 6,725 mp + 0,16 mp + 6,44 mp = 72,19 m2

S built area = 72,19 m2

CONCRETE VOLUME V slab

concrete = S slabbuiltarea x h pl = 58,87 x 0,12 = 7,06 m3 concrete V slab

concrete =7,06 m3 concrete V wall

concrete = S wallbuiltarea x H level = 6,73 x 2,85 = 19,18 m3 concrete

V wallconcrete = 19,18m3 concrete

V beamconcrete = S beam

builtarea x h beam = 6,44 x 0,30 = 1,93 m3 concrete V beamconcrete =1,93 m3 concrete

V columnconcrete = S column

builtarea x H level = 0,16 x 2,85 = 0.45 m3 concrete V columnconcrete =0.45 m3 concrete

V total

concrete = 7,06 + 19,18 + 1,93 + 0,45 = 28,63 m3 concrete V total

beton = 28,63 m3 concrete

CONCRETE ESTIMATE: I concrete = areabuilt S

Vconcrete (m3. concrete / m2 built area)

I concrete = .Abuiltarea

Vconcrete = 19,7263,28 = 0,396 (m3 concrete / m2 built area)

I concrete = 0,396 (m3. concrete / m2 built area)

REINFORCEMENT ESTIMATE: I reinforcement = areabuilt

infS

orcementWre (kg/m2 built area)

Columns I reinforcement columns = areabuilt

_infS

columnsorcementWre [kg / m2 built area]

I ‘reinforcement columns = columnsVconcrete

columnsorcementWre_

_inf [kg / m3. concrete]

Beams I reinforcement beams = areabuilt

_infS

beamsorcementWre [kg / m2 built area]

I ‘reinforcement beams = beamsVconcrete

beamsorcementWre_


Slabs I reinforcement slabs = areabuilt

_infS

slabsorcementWre [kg / m2 built area]

I ‘reinforcement slabs = slabsVconcrete

slabsorcementWre_


Walls I reinforcement walls = areabuilt

_infS

wallsorcementWre [kg / m2 built area]


64

I ‘reinforcement walls = wallsVconcrete

wallsorcementWre_


I total reinforcement = I reinforcement columns + I reinforcement beams + I reinforcement slabs + I reinforcement walls

FORMWORK ESTIMATE: I formwork = .areabuilt S

Sformwork (m2. formwork / m2 built area)

I formwork = I column formwork + I beam formwork + I slab formwork + I wall formwork

I formwork = SbuiltareaSformwork =

builtarea

wallslabbeamcolumnt

SSSSS +++

(m3 concrete / m2 built area)

S columns = 4 x 0,40 x 2,85 + 4x 0,20 x 2,85 = = 4,56 + 2,28 = 6,84 m2 S columns = 6,84 m2 column form S beams 2 x G1 = 4 x 0,30 x 3,80 + 2 x 0,20 x 3,80 = 6,08 2 x G2 = 4 x 3,30 x 4,05 + 2 x 0,20 x 4,05 = 6,48 1 x G3 = 2 x 0,30 x 2,25 + 1 x 0,25 x 2,25 = 1,91 1 x G4 = 2 x 0,30 x 5,25 + 1 x 0,25 x 2,25 = 3,71 S beams = 6,08 + 6,48 + 1,91 + 3,71 = 18,18 m2 S beams = 18,18 m2 beam form

Slab 1 = 25 x 3,8 = 8,55 Slab 2 = 2,25 x 4,05 = 9,11 Slab 3 = 3,8 x 5,25 = 19,95 Slab 4 = 4,05 x 5,25 = 21,26 S slab = 8,55 + 9,11 + 19,95 + 21,26 = 58,87 m2 S slab = 58,87 m2 slab form S wall = 4 x 7,80 x 2,85 + 4 x 0,25 x 2,85 + 8 x 0,15 x 2,85 + 4 x 0,20 x 2,85 +

+ 2 x 8,10 x 2,85 + 4 x 2,85 x 0,30 + 2 x 2,85 x 0,25 = = 88,92 + 2,85 + 3,42 + 2,28 + 46,17 + 3,42 + 1,43 = = 148,48 m2 wall form S wall = 148,48 m2 wall form

I formwork = I formwork columns + I formwork beams + I formwork slabs + +I formwork walls

I formwork = .areabuilt S

Sformwork = areabuilt

wallsslabsbeamscolumns

SSSSS +++

(m2. formwork/ m2. built area)

I formwork columns = .areabuilt

_S

columnsSformwork = 19,7284,6 = 0,095

I formwork beams = .areabuilt

_S

beamsSformwork = 19,7218,18 = 0,252

I formwork slabs = .areabuilt

_S

slabsSformwork = 19,7287,58 = 0,815

I formwork walls = .areabuilt

_S

wallsSformwork = 19,7248,148 = 2,056

I total formwork = 3,22 m2. formwork / m2 built area

5.3.2. ESTIMATE CALCULATION OF LABOR CONSUMPTION FOR CONCRETE, REINFORCEMENT AND FORMWORK PLACEMENT

CONCRETE (class C 20/15 - Cod C) Cod C – Total labor hours required for placing concrete in slabs, beams, columns for constructions with heights of maximum 35 m - 7.8 hr / m3. concrete. I concrete = 0,4356 (m3 concrete / m2 built area) x (7,8) h/ mc = 3.397 man h./m2 built area

I concrete = 3,4 man h/ sq. m built area


65

FORMWORK Cod D - Total labor hours required for erection of reusable plywood panels with sheathing of 15 mm thickness for placing concrete in partition walls and bearing walls for constructions up to 20 m height - 0,95 hr / m2. panel; Cod E - Total labor hours required for erection of reusable plywood panels with sheathing of 15 mm thickness for placing concrete in slabs and beams for constructions up to 20 m height - 1,1 hr / m2. panel; Cod F - Total labor hours required for erection of reusable plywood panels with sheathing of 15 mm thickness for placing concrete in columns and frames for constructions up to 20 m - 1,25 ore / m2. panel; I formwork = I formwork columns x 1,25 + I formwork beams x 1,1 + I formwork slabs x 1,1 + I formwork walls x 0,95 = 0,095 x 1,25 + 0,252 x 1,1 + 0,815 x 1,1 +2,056 x 0,95 = = 0,118 + 0,277 + 0,896 + 1,953 = = 3,244 h/ m2 built area

I formwork = 3,244 man hour/ m2 built area If rate of progress is needed to be calculated, it will be computed according to crew size (number workers) and time (man hours), using the following equation:

)()(....

2

manhrymxprogressofRate =

5.4. ITEM TABULATIONS OF MATERIAL CONSUMPTION AND LABOR COSTS FOR CONSTRUCTION WORKS

Table 5-2. Concrete Concrete placed in slabs, beams, columns for structures with heights up to 35 m. A – mix and placement of concrete class C8/10; B – ditto, class C 12/15; C – ditto, class C 16/20; D – ditto, class C 18/22,5; E – ditto, class C 25/30; F – placement of concrete class (1) in slabs, beams and columns. Measured in cubic meter.

Quantity Item unit A B C D E F

Materials Concrete class 1) m3 1,03 1,03 1,03 1,03 1,03 1,03 Cement 2) kg 283 330 376 422 469 - Graded sand unwashed m3 0,67 0,66 0,65 0,64 0,63 - Coarse aggregate sieved, washed and graded

m3 0,62 0,61 0,6 0,59 0,58 -

Water m3 0,28 0,29 0,3 0,31 0,32 0,1 Small size materials (lumber planks, nails)

% 5 5 5 5 5 5

Labor Skilled worker hr 5,07 5,07 5,07 5,07 5,07 3,72 Unskilled worker hr 2,73 2,73 2,73 2,73 2,73 2,73

Total hr 7,8 7,8 7,8 7,8 7,8 6,45 Equipment Poker vibrator hr 0,7 0,7 0,7 0,7 0,7 0,7 Concrete mix truck 250l hr 0,325 0,325 0,325 0,325 0,325 - Crane 3) hr 0,3 0,3 0,3 0,3 0,3 0,3 Corrections 01. heights greater than 35 m. Increase:


66


Labor Skilled worker hr 0,6 0,6 0,6 0,6 0,6 0,6 Unskilled worker hr 0,4 0,4 0,4 0,4 0,4 0,4 Equipment Poker vibrator hr 0,15 0,15 0,15 0,15 0,15 0,15 Crane 3) hr 0,05 0,05 0,05 0,05 0,05 0,05 02. concrete without finishing Increase:


Labor Skilled worker hr 1,3 1,3 1,3 1,3 1,3 1,3 Equipment Poker vibrator hr 0,7 0,7 0,7 0,7 0,7 0,7 1) the concrete class will be specified; 2) the cement grade will be specified; 3) the type of crane will be specified. Concrete placed in walls of any kind up to the height of 35 m A – mix and placement of concrete class C8/10; B – ditto, class C 12/15; C – ditto, class C 16/20; D – ditto, class C 18/22,5; E – mix and placement of concrete class (1) in walls of any kind; F – mix and placement in round walls, cylindrical reservoirs, cylindrical tanks, water towers, etc. C12/15; G – ditto, class C 16/20; H – ditto, class C 18/22,5; I – ditto, class C 25/30; J – placement concrete class 1) in circular walls, cylindrical reservoir walls, cylindrical tanks, water towers, etc.; Measured in cubic meter.

Quantity Item unit A B C D E F G H I J

Materials Concrete class1) m3 1,03 1,03 1,03 1,03 1,03 1,03 1,03 1,03 1,03 1,03

Cement 2) kg 283 330 376 422 - 330 376 422 469 - Graded sand unwashed

m3 0,67 0,66 0,65 0,64 - 0,66 0,65 0,64 0,63 -

Coarse aggregate sieved, washedand graded

m3 0,62 0,61 0,6 0,59 - 0,61 0,6 0,59 0,58 -

Water m3 0,28 0,29 0,3 0,31 0,1 0,29 0,3 0,31 0,3 0,1 Small size materials (lumber planks, nails)

% 5 5 5 5 5 5 5 5 5 5

Labor Skilled worker hr 4,55 4,55 4,55 4,55 3,2 5,2 5,2 5,2 5,2 3,85 Unskilled worker

hr 2,45 2,45 2,45 2,45 2,45 2,8 2,8 2,8 2,8 2,8

Total hr 7 7 7 7 5,56 8 8 8 8 6,65 Equipment

Poker vibrator hr 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 Concrete mix truck 250l

hr 0,325 0,325 0,325 0,325 - 0,325 0,325 0,325 0,325 -

Crane 3) hr 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3 0,3


67

Corrections 01. heights greater than 35 m. Increase:


Labor Skilled worker hr 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 0,6 Unskilled worker hr 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 Equipment Poker vibrator hr 0,15 0,15 0,15 0,15 0,15 0,15 0,15 0,15 0,15 0,15 Crane 3) hr 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05 02. for concrete without finishing. Increase:


Labor Skilled worker hr 1,1 1,1 1,1 1,1 1,3 1,3 1,3 1,3 1,3 1,3 Equipment Poker vibrator hr 0,7 0,7 0,7 0,7 0,7 0,7 0,7 0,7 0,7 0,7 1) the concrete class will be specified; 2) the cement grade will be specified; 3) the type of crane will be specified. Table 5-3. Formwork Reusable 15 mm thickness plywood forms for placing concrete in: A – pedestals, cup-shaped and machinery footings, and bracings; B – straight wall elevations up to 6 m height; C - curb wall elevations up to 6 m height; D – partition walls and bearing walls up to 20 m height ; E – slabs and beams for constructions up to 20 m height; F – columns and frames for constructions up to 20 m height; G – aqueducts, channels and annexes; H – joints between wall panels; I – the extremities of members that are supported by columns, beams, arches, trusses etc., and for the concreting of the extremities of prefabricated beams; J – exterior tie beams. Measured in cubic meters.


Materials Plywood panel with sheathing of 15 mm thickness

m2 0,09 0,11 0,11 0,11 0,13 0,15 0,09 - - 0,18

Lumber planks m3 0,00035 0,001 0,001 0,001 0,001 0,0015 0,0005 0,002 0,004 0,001 Round wood sections

m3 0,0005 0,0015 0,0017 0,0015 - - 0,007 - - -

Base plate m3 - 0,001 0,002 0,001 0,001 0,001 0,002 0,002 0,002 0,001 Release agents kg 0,12 0,12 0,12 0,12 0,12 0,12 0,12 0,12 0,12 0,12 Column formwork steel yokes

kg - - - - - 0,08 - - - -

Plywood veneer type P 15 mm thickness

m3 - - - - - - - 0,0025 0,004 0,0005

Accessories % 8 8 9 8 3 13 8 9 15 6 Labor Carpenter hr 1 0,8 1,52 0,77 0,94 1 1,32 1,5 1,88 1,28 Unskilled worker hr 0,1 0,15 0,18 0,18 0,16 0,25 0,18 0,1 0,12 0,17

TOTAL hr 1,1 0,95 1,7 0,95 1,1 1,25 1,5 1,6 2 1,45 Equipment Crane 1) hr - - - 0,02 0,02 0,02 - 0,002 0,002 0,02


68

Corrections 01. structures with heights of H = 20-35 m. Increase:


Labor Carpenter hr - - - 0,03 0,04 0,05 - - - 0,05 Equipment Crane 1) hr - - 0,02 0,002 0,002 0,002 - - - 0,002 02. for constructions with heights of H = 35 – 60 m. Increase:


Labor Carpenter hr - - - 0,05 0,06 0,06 - - - 0,06 Equipment Crane 1) hr - - 0,0025 0,0025 0,0025 0,0025 - - - 0,0025 03. for constructions with heights of H = 60…80 m. Increase:


Labor Carpenter hr - - - 0,07 0,08 0,08 - - - 0,08 Equipment Crane 1) hr - - 0,003 0,003 0,003 0,003 - - - 0,003 1) the characteristics of machinery will be specified. Shores (props) for telescopic steel joists used for casting isolated beams, for slabs with monolithic beams and for normal slabs with total loads on formwork of maximum 5000 daN /mp (500 kgf/mp), shores for structures with heights up to 20 m including beams supported on steel props positioned at 1,0 m. A – telescopic joists GE 1 (3-5 m); B - telescopic joists GE 2 (4-6 m); C - telescopic joists GE 3 (6-9 m). Other types of props are included separately. Measured on m2 of slab.

Quantity Item unit A B C

Materials Wooden battens m3 0,0001 0,0001 0,0001 Telescopic steel joist GE 1 (3-5 m) kg 0,07 - - Telescopic steel joist GE 1 (4-6 m) kg - 0,09 - Telescopic steel joist GE 1 (6-9 m) kg - - 0,1 Labor Carpenter hr 0,52 0,42 0,3 Unskilled worker hr 0,10 0,13 0,1 Total hr 0,7 0,55 0,4 Equipment carne 1) ore 0,01 0,008 0,005 01. When telescopic steel beams are supported directly on walls or form panels for walls. Decrees:


Labor Carpenter hr 0,15 0,12 0,1 02. Structures with heights of 20-35 m. Increase:


Labor


69

Carpenter hr 0,03 0,02 0,02 Equipment Crane 1) hr 0,005 0,004 0,003 03. Structures with heights of 35 - 60 m. Increase:


Labor Carpenter hr 0,06 0,04 0,03 Equipment Crane 1) hr 0,008 0,006 0,004 04. Structures with heights of 60 –80 m. Increase:


Labor Carpenter hr 0,11 0,09 0,06 Equipment Crane 1) hr 0,01 0,008 0,006 Shores with telescopic props, used for erection of prefabricated slabs with and without loops, for precast cast in place slabs, for casting monolitical slabs with precast slabs A – type PE 3100R; B – type PE 5100 R. Measured in units.

Quantity Item unit A B

Materials Steel prop PE 3100 R hr 0,25 - Steel prop PE 5100 R hr - 0,41 Wooden battens m3 0,0005 0,0005 Labor Carpenter hr 0,3 0,38 Unskilled worker hr 0,15 0,2 Total hr 0,45 0,58 Table 5-4. Reinforcement Fabrication and erection of steel reinforcement in structural members: A – walls, bent bars with diameters up to 8 mm inclusive; B – ditto, with diameters over 8 mm; C – beams and columns, bend bars with diameters up to 8 mm inclusive; D – ditto, with diameters over 8 mm; E – slabs, bent bars with diameters up to 8 mm inclusive; F - ditto, with diameters over 8 mm; G – special constructions (reservoirs, water towers, bins, barrel vault structures, trusses, thin plated roofs, etc.) bent bars with diameters up to 8 mm inclusive; H – ditto, with diameters over 8 mm; I – creating monolitical continuance for linear members (beams, columns, frames, etc.); J – aqueducts, channels and annexes. Measured in kilograms.


Materials Steel type 1) kg 1,03 1,03 1,03 1,03 1,03 1,03 1,03 1,03 1,03 1,03 Normal wire D=1,25mm kg 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 Spacers 2) no. 0,3 0,3 0,3 0,3 0,3 0,3 0,25 0,25 0,25 0,25 Labor Ironworker hr 0,085 0,07 0,09 0,065 0,075 0,06 0,11 0,09 0,215 0,075 Unskilled worker hr 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 0,1 Total hr 0,095 0,08 0,1 0,075 0,085 0,07 0,12 0,1 0,23 0,085 Equipment Crane 3) hr 0,001 0,001 0,001 0,001 0,001 0,001 0,001 0,001 0,001 -


70

type of steel, type of spacer (plastic or mortar) and crane characteristics will be specified. Welded mesh reinforcement for constructions up to 35 m, placed in: A – partition walls and bearing walls; B – slabs; C – special constructions. Measured in kilograms


Materials Wire meshes for reinforcing concrete 3) kg 1 1 1 Wire D=1,25 mm kg 0,01 0,01 0,01 Spacers 2) no. 0,3 0,3 0,3

Steel type 1) kg 0,01 0,01 0,01 Labor Iron worker hr 0,035 0,03 0,045 Unskilled worker hr 0,005 0,005 0,005 Total 0,04 0,035 0,05 Equipment Crane 4) hr 0,001 0,001 0,001 type of steel (> 8 mm), type of spacer (plastic or mortar), type of steel and diameter of main mesh bars and crane characteristics will be specified.

REFERENCES 5-1 Gould F., Joyce N. Construction Project Management. Second Edition. Prentice Hall, 2003. 5-2 La Londe W., Janes M., Concrete Engineering handbook. McGraw-Hill Company Inc., 1961. 5-3 Nunnally S.W. Construction Methods and Management. Sixth Edition. Prentice Hall, 2003. 5-4 Mueller fr., Integrated cost and schedule control for construction projects. Van Nostrand Reinhold

Company, 1986. 5-5 Ridloff R., A practical guide to construction lending. Van Nostrand Reinhold Company, 1986. 5-6 US Army Corps of Engineers. Directorate of Military Programs Engineering Division. Architectural and

engineering instructions for cost control during design (Design-to-Cost), 1996. 5-7 US Army Corps of Engineers. Directorate of Military Programs Engineering Division. Engineering

Instructions. Construction Cost Estimates. EI 01D010, 1997.


71

CHAPTER 6. CONCRETE WAREHOUSE STRUCTURAL FRAME ERECTION

6.1. GENERAL CONSIDERATIONS Precast-concrete construction is based upon good practical planning along with mass-

production methods. A successful design is one that uses a minimum number of assembly elements, having least erection weight and the greatest strength per unit weight of framing. It requires a complete design of connection details and an investigation of stresses involved in the sequence of erection, which will influence the framing and design of the elements.

Generally, it is essential that the number of various shapes and sizes of the precast elements be kept to a minimum. This allows maximum reuse of the moulds and reduces forming, casting, and handling costs.

The layout of the frames and enclosures is controlled by the available handling and erection equipment. While lifting capacity is always a factor, the maneuverability of the equipment within the building area may be facilitated by changes in column spacing, direction of main framing, or erection sequences. Advantages of precast-concrete construction: speed of construction, optimum use of materials, controlled production conditions, and economy do to the fact that the materials can be better utilized and wastage can be kept to a minimum.

Limitations of precast-concrete construction: lack of flexibility and if precast units are small in quantity, the construction cost will be high, while storage and transportation of precast units can also be a problem for construction sites located in congested urban areas.

Figure 6-1. Transverse girder beam warehouse Caption: 1. Cup foundation, 2. Edge column with corbel to support bridge beam, 3. Central column with or without corbel, 4. Edge column without corbel, 5. Foundation beam, 6. Bridge beam, 7. Transverse girder beam L= 12, 15, 18, 21 and 24 m span, 8. Roof slabs (1,5x6 m), 9. External cladding ACC or sandwich prefabricated panel (polystyrene and ACC), 10. ACC blocks, 11. Mineral wool plates/ ACC plates, 12. Mineral wool plates, 13. Heavy traffic concrete plates, 14. Pedestrian concrete plates. Source: MACON S.A.


72

Figure 6-2. Longitudinal girder beam warehouse. Caption: 1. Cup foundation, 2. Edge column with corbel to support bridge beam, 3. Central column with or without corbel, 4. Edge column without corbel, 5. Foundation beam, 6. Bridge beam, 7. Eave beam, 8. Longitudinal girder beam G6T (central or edge), 9. Central longitudinal girder beam GΨ6-15, 10. Central longitudinal girder beam GΨ6-118, 11. Longitudinal girder beam G12, 12. Roof slab ECP 1,5x9, 13. Roof slab 1,5x12, 14. Roof slab 1,5x15, 15. Roof slab 1,5x18, 16. ACC blocks, 17. External cladding ACC or sandwich prefabricated panel (polystyrene and ACC), 18. Mineral wool plates, 19. Polystyrene plates, 20. Pedestrian concrete plates, 21. Heavy traffic concrete plates Source: MACON S.A.

6.2. JOB PLANNING The construction of a precast-concrete structure requires considerable planning and

development of details. All planning, from working drawings to the completed structure, must be completed in the early stages. The erection planning of structure will consist of methods and details regarding: 1. Preliminary execution of works that will consist of the following steps:

- Transport, yard casting and storage of precast units. - Inspection of units after transport and storage. - Unit preparation before erection. - Selection of lifting devices and equipment. - Materials and labor scheduling. - Necessary requirements for health, safety and fire assurance.

2. Erection of precast elements, will consist of the following steps: - Erection method. - Sequence, schemes and procedures for unit erection. - Sequence of member erection. - Ground location and position layout of precast units before erection. - Routs and work stations for cranes. - Routs and stops for trailers.


73

- Unit installation detailing sequences. - Preliminary positioning of units. - Inspection of erection execution in provisory position and correction of dimensional

tolerances. 3. Final connections between elements. Table 6-1. Erection characteristics table

Prefab characteristics Characteristics lifting device

Erection characteristics

Crane characteristics

Pref

ab m

embe

r

Pref

ab. t

ype

Qp

(ton

es)

Hp

(m)

Dis

tanc

e be

twee

n lif

ting

inse

rts (

m)

Typ

e lif

ting

devi

ce

Qd

(ton

e)

Hd

(m)

Loa

d (t

one

max

)

Qt (

tone

s)

Ht (

m)

Rap

(m)

Typ

e cr

ane

Qtf

(ton

es)

H (m

)

R (m

)

F (m

)

EC (SM)

CC (SC)

GB (GP)

BB (GR)

RS (EA)

6.3. PRELIMINARY EXECUTION WORKS The details and planning of erection will materially affect the earlier phases of casting, storage, and handling.

6.3.1. STANDARDIZED PREFABRICATED REINFORCED AND PRESTRESSED CONCRETE MEMBERS

The selection of standardized prefabricated reinforced and prestressed concrete members shall be base on: geometrical and surface characteristics, type of structure designed, load bearing capacity, execution and environment conditions. Table 6-2. Typical prefabricated ground floor warehouse concrete members

Height (cm)

Item L Leng

th (cm)

l Widt

h (cm)

H max

h min

W Weight

(kg)

V Volume

(m3)

Concrete Class

(N/mm2)

Distance between inserts (cm)

Bay (m)

Longitudinal Girder Beam (Source: IPCT, 1988)

G 6 T 595 45 55 45 2250 0,900 C 40/32 545 6x18 6x15 6x12

G 6 T pp1 595 45 55 45 2250 0,900 C 30/25 545 6x18 6x15 6x12

G 6 – 6 - pp 595 35 50 40 1414 1,566 C 30/25 545 6x6 G ψ 6-15 595 70 65 55 3420 1,368 C 40/32 555 6x15 G ψ 6-15 pp 595 70 65 55 3420 1,368 C 40/32 555 6x15 G ψ 6-18 595 70 70 60 3620 1,448 C 40/32 555 6x18

1 abv. pp - partially prestressed


74

G ψ 6-18 pp 595 70 70 60 3620 1,448 C 40/32 555 6x18

G12-12-1 /pp 1195 60 (70) 80 75 7000

(7400) 2,800

(2,960) C 40/32 C 50/40 1135

12x18 12x15 12x12

G12-12-2 /pp 1195 60 (70) 80 75 7000

(7400) 2,800

(2,960) C 40/32 C 50/40 1135 12x12

G ψ 12-15/pp 1195 70 99 85 8640 3,456 C 40/32 1135 12x15 G ψ 12-18/pp 1195 70 104 70 9060 1100 12x18

G 12 – 24 -1/2 1195 60 (70) 80 75 7000

(7400) 2,80

(2,90) C 40/32 C 50/40 1135 12x24

G 9-2 870 70 103 90 6160 2,463 C 50/40 810

Gm-9 870 50 80 67 3860 1,544 C50/40 810

9x12 9x15 9x18

Longitudinal Girder Beam used in the Food Industry (Source: IPCT, 1988) G ψ A6-18 575 70 70 70 3858 1,543 C 40/32 535 18x6 G cA - 6 595

575 45 55 55 2963 (2863)

1,185 (1,145) C 40/32 555

(525) 12x6

G mA-6 595 575 45 55 55 2454

2372 0,982 0,949 C 40/32 555

(525) 12x6 18x6

G A 12-12 1195 70 110 110 9079 3,632 C 40/32 1135 12x12 G mA -12-12 1175 70 110 110 8972 3,589 C 40/32 1125 12x12 GR 12-T 1192 60 123 125 9854 3,942 C 40/32 1132 12x12

Transverse Girder Beam (Source: IPCT, 1988) G 12-6 /T 1195

1180 35 32

80 95

40 45

3235 3325

1,294 1,330 C 40/32 1145 12x6

G 15-6 /T 1495 1480 40 95

113 50 60

5270 5690

2,108 2,276 C 40/32 1445 15x6

G 18-6 /T 1795 1780

43 40

110 125

55 66

7120 7290

2,848 2,915 C 40/32 1455 18x6

G 12-4 1180 40 105 55 4560 1,824 C 40/32 1095 12x12 12x9

G 15-4 1480 50 138 86 8200 3,280 C 40/32 1300 15x12 15x9

G 18-4 1780 50 145 86 10360 4,143 C 40/32 1600 18x12 18x9

G 21-1 2080 60 147 90 15200 6,08 C 50/40

C 40/32 1770 21x6 21x9

21x12 G 24-1 /pp 2380 60 150 90 17700 7,08 C 50/40

C 40/32 2200 24x6 24x9

G 24 -12- 2 2370 70 175 105 26700 10,667 C 40/32 2200 24x12 Bridge Beams (Source: IPCT, 1988)

GR 6-100 592 100 5040 2,013 GR 6-80 592 80 3670 1,468 GR 6-60 592

55 60 2960 1,185

C 22,5/18 390

GRP 9-100 892 55 100 6000 2,30 C 40/32 792 GRP 12-85 1195 60 85 7,35 2,94 C 40/32 1055 GRP 12 -125 1192 60 125 10,30 3,95 C 40/32 1055

Span 12… 30 m

Roof Slabs (Source: IPCT, 1988) ECP (G) 9x1,5

890 149 40 20 2743 2778 2813

1,097 1,111 1,125

C 40/32 850

ECP12x1,5 /pp 1190 149 50 23 3930 1,57 C 40/32 1105


75

ECP 15x1,5 /pp 1465 149 65 25 5930 2,372 C 40/32 C 30/25 1380

ECP 18x1,5 1765 149 75 30 6830 2,789 C 40/32 1665 ECPG 12x1,5 1190 149 50 23 4075 1,63 C 40/32 1105 ECPG 15x1,5 1465 149 65 25 5930 2,372 C 40/32

C 30/25 1380

ECPG 18x1,5 1765 149 75 30 6970 2,789 C 40/32 1665 ECP 9x1,5 890 40 20 2743 1,097 C 50/40 850 ECP 12x1,5 /pp 1190 50 23 3930 1,570 C 50/40 1105 ECP 15x1,5 1465 65 25 5510 2,204 C 50/40 1380 ECP 18x1,5 1765

149

75 30 5830 2,731 C 50/40 1665 EP 6x1,5 593 149 24 1500 0,600 C 30/25 513 C 12x1,5 1190 149 50 24 4180 2,916

1,672 C 40/32 C 30/25 1105

π 12x3,0 1190 299 7290 2,916 C 30/25 1105 ACC Plates (Source: IPCT, 1988)

TB 0,6x3,0 293 59,7 12,5 15 153

185 0,212 1,258 GB 35

TB 0,6x0,6 590 598 59,7 25 620

630 0,86

0,875 GB 35

Cup shaped foundations for warehouses without bridge cranes (Source: IPCT, 1988) bp Bp lg1 lp1 Lp1 lg2 lp2 Lp

2 H Weight

(kg) Class Vol-

ume PF1 20 28 51 91 98 51 91 98 70 1200 0,48 PF2 25 33,5 61 111 119 61 111 119 80 2000 0,80 PF3 30 39 76 136 145 76 136 145 90 3300 1,32

PG1R 30 39 76 136 145 66 126 135 90 3150 1,26 PG2R 35 44 86 156 165 66 136 145 95 4175 1,67 PG3R 35 44 86 156 165 76 146 155 95 4375 1,75 PG2 30 38,5 66 126 134 66 126 134 80 2625 1,05 PG3 35 44 76 146 155 76 146 155 90 3946 1,58 PG4 45 54,5 86 176 185 86 176 186 100 6530

C 15/10

2,61 Figure 6-3. Standardized catalog prefabricated reinforced and prestressed concrete members

Cup shaped foundations (Source: IPCT, 1988)


76

Longitudinal Girder Beam (Source: IPCT, 1988)


77


78


79


80


81


82

Transverse Girder Beam (Source: IPCT, 1988)


83


84


85

Bridge Beams (Source: IPCT, 1988)


86

Roof Slabs (Source: IPCT, 1988)


87


88


89


90

6.3.2. MANUFACTURING, TRANSPORT AND STORAGE OF PRECAST UNITS Precast-concrete elements are cast or manufactured in: permanent factories, temporary

factories, off-site casting yards, or supplied from a combination of these facilities. Transport of units is normally provided from these facilities to the site by trucks, only after a very careful examination of the following: shape, dimensions, and weights of prefabricated units, financial comparison of estimated site-produced castings and factory-produced and delivered castings, type and capacity of transport means, space available on the job site and correct position for transport of member, availability, and quality of roads etc.

Trucks can be classified in: - Straight or articulated trailers (a straight truck is one in which all axles are attached to a

single frame while an articulated truck is one that consists of two or more separate frames connected by suitable couplings).

- Truck tractor that are designed primarily for pulling and carrying part of the weight and load of a semi trailer.

Other types include: full trailer, deck trailer, flat bed trailer, lorry trailer, single axle trailer, heavy duty trailer, low-bed trailer etc. of 8-20 tones.

Figure 6-4

Typical trailers

Source: Suman R., 1989.


91

Storage and transportation of precast units can be a problem for construction sites located in congested urban areas. Storage represents an intermediate faze between the prefabricated production and there transport to the site for assembly. The storage yard can be located in the prefabricated manufacturing shop or on the job-site. If it is located on the job-site, it will be as close as possible located near the crane but protected against other construction activities and erection of castings without interference with the erected framework or with the erection equipment. Precast units will be stored, raised off the ground, in such a manner as to avoid contact with dirt, oil, and grease, to reduce any kind of degradation, and to identify each type of unit as easy as possible.

Source: SC SOMACO SA, 2003

Figure 6-5. Typical storage of reinforced and prestressed concrete members

Source: Prefabricate Vest

Figure 6-6. Typical

prefabricated cup shaped foundations

Source: Preconstructa AEBTE,2003


92

6.3.3. INSPECTION OF UNITS AFTER TRANSPORT AND STORAGE The precast elements shall be visually checked for defects (cracks, voids etc.) when

the forms are removed off the trailer, when the strands are cut, or when they are placed in temporary or permanent storage. Any significant defect should be reported immediately with the description of its size, type, and location. The Engineer will decide if the defect needs further inspection, what type of repair, or if it is needed

6.3.4. UNIT PREPARATION Unit Preparation Before Erection - during lifting, storage and transport of precast units it is possible that the elements will be exposed to dirt, mud, oil, and grease. They will be cleaned through washing them with water, and by wirer brushing.

6.3.5. LIFTING DEVICES The planning of erection (lifting) devices and details for their attachment to the

elements must be completed. It is obvious that changes in methods or details of any phase of the construction may be difficult after actual commencement of that part of the work.

A lifting device consists of two main parts: the anchorage element embedded in the precast unit and the attachment element, which is attached to the anchorage to fasten the lifting line to the component.

To provide adequate strength, the anchorage should bear against the reinforcement. A simple and common device is to embed several steel loops in the concrete, leaving the loop exposed for attachment of the crane hook.

Selection of proper anchors for lifting precast concrete products requires consideration of a number of factors including the type of load, type of lift, concrete shape and weight, configuration, thickness, and strength of the precast component, concrete compressive strength at time of initial lift, number of lifting points and type of rigging to be used, direction of pull (cable or sling angle), reinforcement, ease of attachment to product, compliance with safety requirements and ease of use during final installation and cost.

The location of lifting devices in the components should be carefully considered, taking full account of the special loading that will be imposed on the concrete as a result of tilting, lifting, or moving the component, including an allowance for impact. For example, raising a horizontally cast precast panel to a vertical position (e.g. columns cast on site) may induce stresses in the concrete that exceed any loading that may be imposed on the panel after it has been installed in a structure.

Spreader beam for lifting precast beams in two points of pickup

Spreader beam for lifting precast roof slabs with four wire cables in four points of

pickup

Spreader beam for lifting precast beams with two wire

cables in two points of pickup

Figure 6-7. Typical lifting devices for precast concrete members Source: Ilinoiu G., 2003; Suman R., 1989, Trelea A., 1997.

Selection of the lifting device and its location should be based on the manufacturer’s recommendation and an engineering analysis of the proposed installation. The locations and details of lifting and handling devices should be shown on the shop drawings.


93

A spreader beam is used in transmitting vertical loads from the two surface inserts to a single point at the lifting hook. Large or heavy panels are often lifted with a four-point pickup with sheaves on the spreader for load equalization.

6.3.4.1. TYPICAL LIFTING DEVICES These shall include: type, height, bearing capacity, length between lifting cables.

Table 6-3. Lifting devices for columns Source: Popa R., Teodorescu M., 1992.

Item U 119

Qd (kgf) Hd (mm) Qmaxpref

150 3290 7,0 tf

Item U 186 Qd (kgf) Hd (mm) Qmax

pref

50 1960 4,0 tf


pref

460 5630 10,0 tf


pref

993 4300 10,0…17,00 tf


94


pref

1300 3500 17,0…25,00tf

Table 6-4. Lifting devices for beams Source: Popa R., Teodorescu M., 1992.

Item U 272 Qd (kgf)

Hd (mm)

Qmaxpref

763 3120 6,0tf

Item U 273 Qd (kgf)

Hd (mm)

Qmaxpref

2030 3190 16tf


95

Item U 300 Qd (kgf)

Hd (mm)

Qmaxpref

1980 2890 10,0tf

Table 6-5. Lifting devices for beams and roof slabs Source: Popa R., Teodorescu M., 1992.

Item U 316 Qd (kgf)

Hd (mm)

Qmaxpref

510 4130 3,0tf

Item U 317 Qd (kgf)

Hd (mm)

Qmaxpref

1736 3427 8,0tf


96

Item U 318 Qd (kgf)

Hd (mm)

Qmaxpref

2763 4587 14,0tf

Item U 319 Qd (kgf)

Hd (mm)

Qmaxpref

2000 5200 19,0tf

Item U 329 Qd (kgf)

Hd (mm)

Qmaxpref

2887 4700 19,0tf


97

Item U 330 Qd (kgf)

Hd (mm)

Qmaxpref

4458 4870 18,0tf

Item U 203A Qd (kgf)

Hd (mm)

Qmaxpref

493 2246 4,5tf


98

Item U 203B Qd (kgf)

Hd (mm)

Qmaxpref

630 3115 4,5tf

Table 6-6. Universal lifting devices Source: Popa R., Teodorescu M., 1992.


pref (tf) 22 28 45

1300 1600 1800

1,0 3,2 6,4

Item GRU Qd (kgf) Hd (mm) Qmax

pref (tf) 143 4500 6,4tf


99

6.3.6. SELECTION OF LIFTING EQUIPMENT A crane may be defined as a machine for lifting loads by means of a cable. The use of

cranes has greatly increased in the construction industry due mainly to the need to raise the large and heavy prefabricated components.

A crane consists primarily of a power unit mounted on a carrier with a hoist, a boom, and control cables for raising and lowering the load and boom.

The boom can be a welded steel lattice or a hydraulic boom made of 1 articulated base element and several telescopic sections, that are extended and retracted hydraulically (from 5 to 30 m) allowing the crane to be completely self-contained.

A jib, an extension to the end of the boom, is used for extending the height to which loads can be lifted; it can be added to a lattice boom or a hydraulic boom. A jib decreases the lifting capacity of the crane and should be used with caution. Two basic jib formats for this type of crane are available, namely the folding lattice jib and the telescopic jib.

Outriggers are hydraulic telescoping supports (4-6 suspension cylinders, individually controlled in both – horizontal and vertical – directions from the frame).

Three basic types of cranes are commonly used in warehouse erection, they are: track-mounted cranes, lorry-mounted cranes and self-propelled cranes. There are several variations of each type, and each is available in a wide range of lifting capacities and boom lengths, thus providing the contractor with a generous selection of options.

The track-mounted cranes (crawler crane) come in a wide variety of designs and capacities, generally with a 360° rotation or slewing circle, a low pivot, and jib. Advantages: - Mobility on the job site with load on hook. - It can lift relatively heavy loads (10…900

kN) without the use of outriggers. - Capacities ranges similar to the lorry

mounted cranes, height capacities 60 m; Limitations: slow speeds and large bulk, the crane cannot move from one site to another without some disassembly and the use of 10 tone trailers to transport it between sites. Characteristics: The jib is of lattice construction with additional sections and fly; jibs to obtain the various lengths and capacities required. Figure 6-8. Track-mounted crane Caption: 1. Hook; 2. Jib; 3. Cab; 4. Boom suspension rope; 5. Hoist rope; 6. Pendant rope. Source: Chudley R., 1999.


100

Lorry-mounted cranes come in a wide variety of designs and capacities, generally with a 360° rotation or slewing circle, a low pivot, and jib. To improve the mobility of the crane from one site to another lorry-mounted cranes have rubber tires and an additional cab were a driver drives the crane from site to site on public roads. Characteristics: The crane is operated by a separate crane engine and controls. The capacity of lorry-mounted cranes ranges up to 2000 kN in the freestanding position but this can be increased by using the jack outriggers. Their height capacity range to 100 m. Mobile lorry cranes can travel between sites at speeds of up to 48 km/h, which makes them very mobile, but to be fully efficient they need a firm and level surface from which to operate. Figure 6-9. Lorry mounted crane Caption: 1. Hook; 2. Pendant ropes; 3. Hoist ropes; 4. Engine; 5. Jib. Source: Chudley R., 1999.

Self Propelled Cranes (also referred to as a crane truck) is a portable boom crane mounted on an industrial truck. They can be distinguished from other mobile cranes by the fact that the driver has only one cab position for both driving and operating the crane. Characteristics: They are small capacity machines having a fixed boom or jib length, with small radii and low lifting capacities 10 t. They are extremely mobile but to be efficient they usually require a hard level surface from which to work. Road speeds obtained are in the region of 30 km/h. Figure 6-10. Self propelled crane Caption: 1. Hook; 2. Boom; 3. Cabin; 4. Chassis; 5. Outriggers; 6. Boom suspension ropes; 7. Hoist ropes; 8. Pendant ropes. Source: Chudley R., 1999.

Crane selection criteria shall include: capacities cranes, reaches of cranes and clearness required for movement of the equipment and prefabricates without interference with previously erected framing members.


101

The range of cranes available is very wide and therefore actual choice must be made on a basis of sound reasoning, overall economics and technical capabilities: of cranes under consideration, prevailing site conditions and the anticipated utilization of other erection equipment.

Figure 6-11. Crane clearances Caption: a. boom angle; b. maximum clearance height of cabin; c. maximum radius of tail swing; d. center of rotation to boom foot pin; e. height from ground to boom foot pin; f. distance from centre of boom point sheave to bottom of hook; g. clearance radius of boom; h. length of boom. Source: Andres C., 1998.

The criteria by which to chose cranes is based on the following considerations: (1) Maximum hook height (H). (2) Extended / retracted boom length (f). The shallower the boom's angle, the less load

it can lift. The longer the boom, the less load it can lift. (3) Clear radius of boom (R). Should the load be lifted at a grater radius, the angle of the

boom be decreased, the load capacity of the crane is greatly decreased. (4) Lifting capacity (Q). To assure the cranes stability, it is necessary to respect the

following restriction: 0,75 lifting capacity of crane ≤ tipping load of crane If not possible then the stability of the footing must be increased by leveling and

completely supporting them by their outriggers, which must be fully extended and positioned firmly on stable ground.

Depending on the circumstances under which a load is lifted, either of these can govern the safe lifting load of the crane. Loading charts are provided with each crane and must be adhered to religiously. Load charts should never be exceeded. (5) Traveling clearance for crane (S = min. 500 mm) given by maximum radius of tail

swing, width of chassis or length of outriggers.


102

6.3.5.1. TYPICAL TYPES OF CRANES Figure 6-12. AMT 950. Source: ECCON

Table 6-7. Lifting Capacities for Telescopic Boom AMT 950

Boom Length (m) Radius (m) 5,,6 9,2 12,6 16,1 19,6 23,1 26,6 30,0 2,5 18,7 40,0 25,0 23,0 19,0 15,7 3,0 14,5 32,0 25,0 21,5 18,2 15,2 12,1 9,5 4,0 27,0 22,0 18,5 16,2 13,8 12,1 9,5 S,0 21,0 19,3 16,0 14,1 12,3 10.8 8,9 6,0 17,0 16,6 14,0 12,4 10,9 9,8 8.1 7,0 133 12,4 11,0 9,9 8,9 7,5 8.0 10,1 10,4 9,9 8,9 8.0 6,9 9,0 8,1 8,2 8,6 8,0 7.4 6,5

10.0 6,7 7,0 73 6,8 6,0 12,0 5,3 5,1 5.2 5,5 5,1 14,0 4,1 4,4 4.1 4,4 16.0 3,2 3,5 3,6 3,4 18,0 2,7 3.0 2,6 20,0 2,1 2,4 2,1 22.0 2,0 1,6 24.0 1,0 1,3 26,0 1.0


103

Figure 6-13. DST-0285. Source: BUMAR – LABEDY S.A.

Table 6-8. Lifting Capacities for Telescopic Boom DST-0285

Boom Length (m) R (m) 10 15 20 24 R (m) 10 15 20 24 3.2 28 10 5,4 5,3 5,0 3.5 26,5 18,0 11 4,4 4,4 4,2 4.0 24,0 16,9 12 3,6 3,6 3,5 4.5 21,5 15,9 13 3,0 3,0 3,0 5.0 19,1 14,9 11,0 14 2,5 2,5 6.0 14,6 12,8 9,9 15 2,1 2,1 6.5 12,7 11,6 9,3 7,5 16 1,7 1,7 7.0 10,9 10,6 8,7 7,2 17 1,4 1,4 8.0 8,2 8,4 7,6 6,5 18 1,2 1,1 8,5 7,0 7,4 7,0 6,2 19 0,9 9,0 6,6 6,4 5,8 20 0,7


104

Figure 6-14. DST-0505. Source: BUMAR – LABEDY S.A.

Table 6-9. Lifting Capacities for Telescopic Boom DST-0505

Boom Length (m) Radius (m) 11,1 15,1 19,1 23,1 27,1 31,1 35,1 11,1 3.0 4,0

50.0 38.0

28.0 28.0 25.5 21.0

5.0 6.0

30.4 23.7

24.7 21.4

22.7 20.0

19.1 17.1

15.0 15.0 12.0 4.0

3.0 7.0 8.0

19.2 14.7

18.0 14.7

17.2 14.5

15.2 13.3

13.5 1.9

11.0 9.9

9.0 8.3 2.0

9.0 10.0 11.6 11.4

9.0 11.7 9.5

11,3 9.4

10.4 8.8

8.9 7.8

7.7 7.0

11.0 12.0 7.6

6.2 7.7 5.9

7.5 6.0

7.3 5.8

6.8 5.8

6.3 5.6

13.0 14.0 4.8 4.9

4.2 5.1 4.2

4.7 4,2

5.0 4.3

5.0 4.3

15.0 16.0 3.5

2.8 3.7 3.2

3.7 3.2

3.6 2.9

3.7 32

17.0 18.0 2,1 2.7

23 2,7 2.2

2.5 2.2

2.7 2.2

19.0 20.0 1.8

1,3 1.9 1.6

1.9 1.6

1.9 1,6

21.0 22.0 0.8 1.3

1.0 1.3 1,0

1.3 1.0

23.0 24.0 0.7 0.7

0.4 0.9 0.7


105

Figure 6-15. DUT-0502. Source: BUMAR – LABEDY S.A.

Table 6-10. Lifting Capacities for Telescopic Boom DUT-0502

Boom Length (m) Radius (m) 10.64 14.35 18.10 10.64 14.35 18.10 1 0.64 14.35 18.10 3.0 3.5

6.7 5.5

6.8 5.6

6.8 5.6

11.0 10.8

11.9 10.5

11.9 10.9

21.1 16.0

20.6 15.4

19.0 14.9

4.0 4.5

4.6 3.8

4,7 3.9

4.7 3.5

9.9 9.1

10.0 9.2

9.9 9.1

12.5 10.0

12.3 10.0

11.9 9.8

5.0 6.0

3.2 2.2

3.3 2.3

3.3 2.3

4.0 3.0

3.0 2.3

8.4 7.2

8.1 5.5

8.3 5.9

8.1 5.8

7.0 8.0

1.4 0.9

1.5 1.0

1.5 1.0

2.0 4.7

1.7 4.8

6.0 4.9

3.9 2.7

4.1 2,9

4.2 3.0

9.0 10.0 0.5 0.5 3.7

2.9 3.8 2.9 2.0

1.3 2.1 1.4

11.0 12.0 2.2

1.7 2.3 1.7 0.9

13.0 14.0 1,3

0,5


106

Figure 6-16. TELEMAC HT – 15. Source: UBEMAR

Table 6-11. Lifting Capacities for Telescopic Boom TELEMAC HT

RATED LIFTING CAPACITIES CRANE ON OUTRIGGERS

FRONT Retracted ½ Extended Telescoped

Angle [°] R [m] Q [t] Angle [°] R [m] Q [t] Angle [°] R [m] Q [t]

60 2,20 12,500 50 3.05 12.500 40 3,90 12,500 60 3,60 8,200 30 4,55 11,060 50 4,98 8,200 60 5,10 5,800 20 5,05 7,725 40 6,18 5,550 50 6,91 5,325 10 5,35 6,000 30 7,15 4,550 40 8,48 3,675 0 5,45 5,400 20 7,86 4,050 30 9,75 2,925 10 8,30 3,825 20 10,68 2,512 0 8,45 3,750 10 11,25 2,250 0 11,45 2,175

CRANE ON TYRES

FRONT Retracted 1/2 Extended

Angle [°] R [m] Q [t] Angle [°] R [m] Q [t] 60 2,20 7,000 50 3,05 7,000 40 3,90 5,625 60 3,60 4,250 30 4,55 4,385 50 4,98 4250 20 5,05 3,675 40 6,18 2,850 10 5,35 3,450 30 ,715 2,194 0 5,45 3,150 20 7,86 1,818 10 8,30 1,687 0 8,45 1,575


107

Figure 6-17. TELEMAC HTA -7. Source: UBEMAR S.A.

Table 6-12. Lifting Capacities for Telescopic Boom TELEMAC HTA -7

Boom Length (m) 5,87 5,87-7.5 7,5-9.2 9.2-10,8 10.8-12.7 Radius (m)

Angle [°] Q [t] Angle [°] Q [t] Angle [°] Q [t] Angle [°] Q [t] Angle [°] Q [t] 1.2 2 62 7,0 68 6.5

2.5 56 7,0 64 6,5 69 4.5 3 49 7.0 60 6,0 66 4,5

3.5 43 6,5 55 5.6 62 4,0 67 4,0 4 35 5.5 50 5,2 58 4.0 64 3,8 65 3.8

4,5 25 4,5 45 4.8 55 3,6 61 3.5 63 3.4 5 8 4.0 40 4.0 51 3,6 58 3,5 60 3.0

5.5 33 3,2 47 3.2 55 3,2 57 2.6 6 25 2.8 42 2,9 51 3.0 55 2.3

6,5 8 2.5 37 2,5 48 2.5 52 2.0 7 32 2.2 44 2,0 49 1,7

7.5 25 2,0 40 1.7 46 1.5 B 8 1,8 36 1.6 43 1.4

8.5 31 1,5 40 1.1 9 26 1.2 36 1.0

9.5 19 1,1 32 1,0 10 8 1.0 27 0.9

10,5 22 0,8 11 8 0.8


108

Figure 6-18. LIEBHERR LHM 100. Source: LIEBHERR-Werk Nenzing Gmbh


109



110

Figure 6-20. LIEBHERR LHM 1060/2. Source: LIEBHERR-Werk Nenzing Gmbh

Table 6-13. Lifting Capacities for Telescopic Boom LIEBHERR LHM 1060/2

Boom (m) R (m) 10.9 14.5 18 21,6 25,2 28,8 32.4 35,9 39,5 42 R 10.9 14.5 18 21,6 25,2 28,8 32.4 35,9 39,5 42 2,5 3

60 50 14

16 9.8 8.87.7

9.47.5

9.3 7.6

8.6 7.4

8.9 7.6

8.87,1

6.55,9

3,5 4

47 43

46,5 42,5 31 18

20 6.6 6.15,2

7.4 6,6

6,4 5.4

6,3 5.2

5,34,9

5,44,9

4,5 5

39 35,5

38.5 35

29.1 27,4

25.824.8

24.4 23.1 19.3 20

24 4,6 5,6 4,8

4,6 3,7

4.3 3.5

3,83,2

3.83.3

6 7

30,5 25,7

29.9 25.2

24.3 21,8

22.720,4

20,8 18,7

17,8 16,8

19.2 17,7 15,1 12.7 26

28 3.9 3.5

3.2 2.8

3.1 2.7

2,82,4

2.72.3

8 9 21,7 21.1

18.7 19,8 17

18.516,8

17,2 15.7

15.9 14.6

16.3 15

14.213.2

12.111.5

8,68.2

3032 2,3

2 2

1.72

1,610 12 16

12,2 11.4 11.3

14.510.7

14,4 12

13.5 10.8

13.8 10.8

12.410,7

10.99.8

7.87.2

3436 1.4

1.11.41.1


111

Figure 6-21. LIEBHERR LHM 1040/4. Source: LIEBHERR-Werk Nenzing Gmbh

Table 6-14. Lifting Capacities for Telescopic Boom LIEBHERR LHM 1040/4

Boom Length (m) Radius (m) 9.4 14,5 10,7 24,8 28,4 30 R (m) 9.4 14,5 10,7 24,8 28,4 30 2.5 3

30 28,5 12

14 7,5 7.4 6,1

7,4 6

7 5,9

5,2 4,4

3,5 4

25,9 23.7 16.6 14,6 11.1 16

18 4,8 4,7 3.9

4,6 3,9

3.8 3.3

5 6

20.1 17,1

16,2 15,7

13,1 12.2

10.8 10,5

8.5 8.4 7,5 20

22 3.3 2.8

3,3 2,8

2.9 2,6

7 8 14,5 14,3

12.3 11,6 11,3

9.8 9,3

8,2 8,1

7.4 7.2

24 26 2,3

2 2.3 2

9 10 10.8

9,4 10.7 9.4

8,9 8,6

7,9 7.5

6,9 6,2 28 1.7


112


Table 6-15. Lifting Capacities for Telescopic Boom LIEBHERR LHM 1030

Boom Length (m) 14.3 m

Radius (m)

8,4 14,3 20.1 24.2 26 R (m) 8,4 14,3 20.1 24.2 26 2.5 3

33 30

27,5 27.5 8

9 10,7

9.1 9,9 8,4

9,4 8,1

9.2 7.9

3,5 4 27.5

24,2 15,8 15,7 13,2 10

12 7.7

5.7 7,3 5,5

7 5,5

6.9 5.4

4.5 5 22

20,1 18,5 15.5 14,8

13 12.8 11.3 14

16 4,3

3.5 4,3 3,5

4.3 3.4

6 7 17.4 16

12,9 13,7 11,8

12,2 11,2

11.1 10,5

18 20

2,8 2.7 2.2

2.7 2.2

22 24

1.9 1.9 1.6


113


Table 6-16. Lifting Capacities for Telescopic Boom LIEBHERR LHM 1160

Boom Length (m) R (m) 13.2 17.5 21,8 26,1 30,4 34,7 39 43,3 47,6 52 56,3 60

3,5 160 127 118

4 4,5

115 106

106 97

99 91

86 81 70

5 6

101 93

92 84

86 78

77 68

67 62

55 53 46

7 8

83 74

77 71

71 64

62 57

56 51

49,5 46

43,5 41

37 35,5 30

9 10

64 53

66 60

59 54

54 50

46 42

42,5 39

38,5 35,5

33,5 31.5

28,8 27,4

24,4 23,4 19,5 15

12 14 49,5

37 46,5 40,5

44,5 40

35,5 31

33 28,4

31 26,9

27,7 24,4

24,6 22,2

21,3 19,4

18,5 17

14,3 13,3

16 18 34 26,7 33,5

28,2 27 24

25 22,2

23,6 20,9

21,6 19,3

20 18,2

17,6 16

15,6 14,4

12,3 11,4

20 22 24

20,2 21,4 19,2

20 18,1

18,8 16,9

17.4 15,8

16,6 15

14,7 13.5

13,2 12,2

10,5 9,8


114

24 26 17,1

15,3 16,5 14,9

15,4 14,1

14,4 13,2

13,7 12,6

12,4 11,5

11,3 10,5

9,1 8,5

28 30 13,5

12,1 12,8 11.7

12,1 11.1

11,6 10.7

10,7 10

9,7 9,1

7,8 7.3

32 34 7.8 10,7

9,7 10,1 9,3

9,9 9,1

9,2 8,5

8,5 8

6,8 6,3

36 38 7,4 8,5 7,7 8,4

7,7 7.9 7,4

7,5 7,1

5,9 5,5

40 42 6,2 7.1

6,5 6.8 6,3

6,6 6,2

5 4,6

44 46 4,7 5,8

5,3 5.7 5,3

4,3 3,9

48 50 4,8 4.9

4,6 3,6 3.4

52 54 3,1

2.9

6.4. ERECTION OF PRECAST UNITS Selection of erection method precast units is an important design decision. Each

erection method has its special implications to project cost, construction schedules, traffic, towing system, positioning accuracy, and level of risks during construction.

In many ways, the erection method will determine the: - size and configuration of the precast units; - construction procedure adopted, construction sequence, and schedule; - volume of works, plant and equipment etc.

In general, a thorough evaluation should be made in the early stage of design to determine the effects of the erection methods, because the erection method and equipment to install precast units will affect the structural concept and layout, fabrication of precast components, and construction logistics.

The method of erection will take into account the following: - Assurance of member stability in the structure, during the hole duration of erection

execution. - Process flow and work procedures must create a working front, as fast as possible, for

other processes that will commence afterwards (e.g. electrical installations etc.). - Assurance of complete use of erection equipment time. Methods of erection for prefabricated concrete elements can be planned after two models: - Sequence method - consisting of erecting all the members of the same size and type in

the structure or in one construction faze, the crane having its own route for every member (columns, beams, roof slabs etc.). After the joints for a group of members of the same type are completed (after the grout concrete has reached the necessary strength) another group, which will be supported by the first, will be erected;

- Complex method - consisting of erection organization, in normal sequence of erection (of all members) on a small area of the warehouse, most likely a bay (span-bay), the next phase being the erection of the next bay.

6.4.1. SEQUENCE, SCHEMES AND PROCEDURES FOR UNIT ERECTION The efficiency obtained throughout all sequences of the construction will be

determined by the degree of organization, planning, scheduling, and development of details completed before commencement of work at the site.

Maximum efficiency in erection is obtained by placing the elements in their final position direct from transporting equipment or building storage in one operation. Erection


115

procedures are planned to approach this objective. All other precasting operations are based upon the estimated erection schedule, and any delays in this schedule increase the storage area and dunnage required. Delays in completing connections of erected elements either interrupt the erection or increase the quantity of erection devices. Using additional erection devices to shorten the schedule is justified only when sufficient cured castings are available to ensure a continual operation.

Planning includes a study of casting weights and sizes, capacities and reaches of lifting equipment, and clearances required for movement of the equipment and castings without interference with previously erected framing members. A plan detailing the erection procedure for all elements is drawn and checked to ensure conformance with the above limitations and is then rigidly followed. When choosing the erection scheme, we must take into consideration the following: - Size of bay and span of warehouse. - Height of erection. - Cranes characteristics (regarding the clearance characteristics: height, radius of tall swing,

rotation of boom pin, height to boom pin, clearance radius of boom, length of boom). - Assurance of safety (guard) lanes. - Scheme adopted for precast units. Along side these we must respect the following conditions: - Assurance of member stability during erection. - Process flow and erection operations must create, in a short period, job fronts for jobs that

will proceed. - Assurance of complete use of equipment job time.

Schemes of precast unit erection must include the following: - Ground positioning of precast units before erection. - Order of precast unit erection in accordance with their types and sizes. - Routs and stops for cranes for every type and sizes of precast units. - Indication of members that will be mounted on every crane stop. - Sequences and stops for lorries if the mounting takes places from the lorries.

6.4.2. UNIT ERECTION DETAILING SEQUENCES A grate deal of detailing work is necessary before a member can be erected. Each

member is given an erection mark that it carries through the fabrication stage and subsequently is used on the job to identify the member and its position in the frame. The erection mark is usually placed on the left end of horizontal members to eliminate the possibility of trying to place the member end for end or upside down.

When delivered to the site, the precast unit will be lifted by crane to the designed position, secured with temporary bracing, welded, and finally fixed into position by grout. The general procedure for installation is as follows: - Set precast concrete units, straight, level and square (P42-1971 - Norm for execution of

constructions made of precast panels) to avoid non-cumulative erection tolerances. - Fasten units in place by welding or overlapping. - Provide temporary erection anchorage for welded anchorage system. - Clean field welds with wire brush. - Provide and install sufficient temporary bracing to brace precast units adequately, at all

stages of construction, so that units will safely withstand loads to which they may be subjected. This temporary bracing shall remain in position until all connections have been completed.

- Apply sealant and joint backing to exterior and interior joints to provide a complete weather tight installation.


116

- Clean exposed face work by washing and brushing only, as precast is erected, if required.

6.5. ERECTION CHARACTERISTICS CALCULATION These shall include: total weight to be lifted, total height to be lifted.

Figure 6-24. Erection characteristics of columns

Q total column = Qp column + Q d column

H total column = H d lifting device column + H ’ p column + H safety height

Figure 6-25. General view typical assembly procedure of columns Figure 6-26. Erection characteristics of bridge beams

Q total bridge beam = Qp bridge beam + Q d bridge beam

H total bridge beam=Hd lifting device bridge beam+Hp bridge beam+Hsafety height+H1


117

Figure 6-27. Erection characteristics of girder beams

Q total girder beam = Qp girder beam + Q d girder beam

Htotal girder beam=H d lifting device girder beam+H p girder beam+Hsafety height+H2 Figure 6-28. Erection characteristics of roof slabs

Q total roof slab = Qp roof slab + Q d roof slab

H total roof slab = H d lifting device roof slab + H p roof slab + H safety height+HGB+H2


118

Figure 6-29. General view typical assembly procedure of roof slabs

Source: Preconstructa AEBTE, 2003.

6.6. CONNECTIONS Connections may be either: (a) temporary (also referred to as dry connections) are made by weld, shear anchors, inserts, additional reinforcing bars, posttensioning, or some combination of these can be used to provide this continuity. The temporary connection is usually provided until the permanent ones have been completed.

Figure 6-30. Typical warehouse

connections Source:Preconstructa AEBTE,2003

or (b) permanent (also referred to as wet connections) by concreting grout keys. When precast units are placed adjacent to each other, load transfer between adjacent members is often achieved through a grouted keyway. The keyway may or may not extend for the full depth of the member. The keyway is grouted with one of several different grouting materials (concrete, epoxy resins etc).

Connections to tie precast units together, and to join precast segments into a monolith, are of paramount importance. Both temporary and permanent connections must be designed with careful attention to details and construction procedure to ensure the critical load paths and durability performance. Connections usually consist of dowels, plates/pads or angles embedded in the units ends that bear on similar plates embedded in the supporting section, the connections are usually made by welding them together or by overlapping them, until the final concrete casting has been completed.


119

6.7. INSPECTION OF ERECTION AND CORRECTION OF DIMENSIONAL TOLERANCES

Many factors enter into the quality control of precast/prestressed concrete products. Some of the most important are: - Management commitment to a quality control program. - Qualified personnel for all stages of design and construction. - Testing and inspection of the various materials selected for use. - Clear and complete shop drawings (good production drawings translate documents into

usable information for manufacture, handling, and erection of precast/prestressed units.). - Accurate stressing procedures. - Control of dimensions and tolerances. - Correct positioning of all embedded items. - Proportioning and adequate mixing of concrete. - Handling, placing, and consolidation of concrete. - Adequate curing. - Handling, storing, transporting, and erection of members. - Thorough documentation.

Scope of inspection - in general, precast/prestressed concrete plant inspections should include the following: - Identification, examination, testing, and acceptance of materials. - Inspection and recording of tensioning. - Inspection of beds and forms before concreting. - Checking the dimensions of members, number, size and positions of tendons, reinforcing

steel, other incorporated materials, openings, blockouts, etc. - Regular inspection of batching, mixing, conveying, placing, compacting, finishing, and

curing of concrete. - Observation of test performances for slump, air content, and the preparation of concrete

specimens for strength testing. - Inspection of operations of detensioning, product removal from beds, handling and

storing. - Final inspection of finished product before shipment (i.e. monitoring dimensions, camber,

blockouts, and adequate concrete cover and finishes). - General observation of plant equipment, working conditions, weather, and other items that

may potentially affect the products. Deviations and dimensional tolerances (STAS 6657/3-89; C 156-89)

Tolerance – can be defined as the allowable range of deviation from design specifications expressed as a percentage of the nominal value (the allowable variations in the dimensions of members). Deviation - can be defined as the difference between the measured value and the expected value of a controlled variable.

There will be inevitably differences between the specified dimensions and the actual dimensions of the components and final building. These deviations must be recognized and allowed for. Cast in place and precast concrete is generally manufactured with relatively small deviations but designers should take a realistic view of dimensional variability (inaccuracies).

Particularly in large areas of small elements, minor variations are accumulative, and to neglect an allowance for tolerances will lead to difficulties during erection. Once permissible tolerances are established, they should be stipulated on the detail drawings. Frequent checks of the over-all dimensions of the completed castings and checks during erection will reveal variations, and corrective steps for adjustment should follow immediately.


120

Tolerances must be evaluated on each structure and on the various elements in the structure. This reduction, of course, is not required or desired where the elements are separated by grout, calking, or expansion material.

The plans and drawings for structures frequently specify the permissible variations for lines, grades, and dimensions that the contractor is expected to observe. The tolerances should be realistic, considering the nature of the structure. Tolerances that are more than rigid than justified will increase the cost of a structure unnecessarily.

6.8. CONSTRUCTION PROJECT PLANNING AND SCHEDULING Materials and Labor Scheduling - the job planning required, however, is a sound

investment. The basic nature of precast-concrete construction provides the contractor with close control over all labor and materials, with little effort.

The continuous repetitious operations provide ideal opportunities for perfection of labor and equipment allocation and efficiency. The daily repetitive use of identical quantities of materials reduces waste. Close control and detailed and accurate records can be obtained on materials, labor, costs, and progress on all phases of the work.

The application of basic precasting principles creates a neat and clean working area, both at the casting yard and throughout the construction area. This cleanliness, rarely obtainable in other methods of construction, eliminates waste, promotes efficiency, and discourages accidents. Proper scheduling will permit the installation of foundations and related work during the period that the casting yard is being constructed and put into operation. The elapsed time between storage and erection of the elements, at any specific portion of the building area, will be short. Each area becomes available to the mechanical and other trades immediately upon completion of the precast erection in that area. Therefore, exceptional continuity in the work of those trades can be maintained.


121

6.8.1. EXAMPLE BAR CHART SCHEDULE – GANTT CHART AND LABOR SCHEDULE

ID Task Name Duration1 Task 1. Excavation soil 1 day2 Task 2. Manual diging-Team 1 2 days3 Task 2. Manual diging-Team 2 2 days4 Task 3. Concrete casting leveling layer-Team 1 3 days5 Task3. Concrete casting levelling layer-Team 2 2 days6 Task 4. Concrete casting foundations-Team 1 3 days7 Task 4. Concrete casting foundations-Team 2 2 days8 Task 5. Spreading and compaction- Team 1 4 days9 Task 5. Spreading and compaction- Team 2 3 days10 Task 6. Delivery prefabricated members 20 days11 Task 7. Column erection 5 days12 Task 8. Beam erection 10 days13 Task 8. Roof slab and roof lights erection 10 days14 Task 10. Cladding- Team 1 10 days15 Task 10. Cladding -Team 2 10 days16 Task 11. Flooring - Team 1 6 days17 Task 11. Flooring- Team 2 5 days18 Task 12. Roof covering - Team 1 5 days19 Task 12. Roof covering - Team 2 5 days20 Task 13. Partition - Team 1 6 days21 Task 13. Partition - Team 2 4 days22 Task 14. Finishings - Team 1 12 days23 Task 14. Finishings - Team 2 10 days24 Task 15. Comissioning 2 days

Labor 10 workersLabor 10 workers


Labor 5 workersLabor 5 workersLabor 5 workers








Labor 7 workersLab

S T T S M W F S T T S M W F S T T S M W F S T T S M W F S23 Nov '03 30 Nov '03 07 Dec '03 14 Dec '03 21 Dec '03 28 Dec '03 04 Jan '04 11 Jan '04 18 J


122

6.8.2. EXAMPLE NETWORK SCHEDULES CPM – The Critical Path Method

ST 0

0 0

C 25

0 0 25F 15

25 0 150 25

40 40

Sv 1

65 65

SM 2

66 66

BE 2

69 68

BF 2

70 71

Ic 3

71 72

SM 0

68 68 1

2

BE 2

69 69 3BF 2

72 72 2MS 6

74 74 1

AM 10

50 5816 A 20

66 67

525

2 2 3

Ic 3

75 75 1MG 10

76 76

ME 10

81 81

SI 10

86 86

T 5

91 91

PE 4

93 95

P 5

94 95

F 10

96 98

T 10

96 96

SI 10

96 96

P 5

106 106

PE 4

105 109

F 10

111 111

R 2

121 121

S 0

123 123

25 1 3 1

5

5

5

`2

1

2

105

1114

13102

2

3

10

0

Caption: S – start, C – contracting works, F – financing, A – delivery materials, O – site woks, SV – clear and grub, SM – manual digging, BE – leveling concrete, BF – concrete foundation, IC – spreading and compaction, A – delivery prefabricates, MS – column erection, MG – beam erection, ME – roof slab erection, SI – cladding, P – flooring, T – roof insulation, PE – partition walls, F – finishing, R – commissioning.


123

6.9. HEALTH, SAFETY AND WELFARE REGULATIONS These regulations detail the minimum requirements for lifting devices and equipment. In

summary the main points include: - Examination of all forms of lifting devices to ensure sound construction, materials

appropriate for the conditions of use, adequate strength for the intended task, retention in good order and inspection regularly at intervals depending on use and exposure as determined by a competent person.

- Adequate support, strength, stability, anchoring, fixing and erection of lifting appliances to include an appropriate factor of safety against failure.

- Traveling and slewing cranes require a 500 mm wide minimum clearance provided wherever practicable between the equipment and fixtures such as a building or access scaffold. If such a clearance cannot be provided, movement between the appliance and fixture should be prevented.

- A cabin is required for the crane operator that must provide an unrestricted view for safe use of the equipment. The cabin must have adequate protection from the weather and harmful substances with a facility for ventilation and heating.

- Equipment which can be adapted for various operating radii and other configurations must be clearly marked with corresponding safe working loads for these variables.

- Brakes, controls, and safety devices must be clearly marked to prevent accidental operation or miss-use.

- Safe means of access is to be provided for examination, repair, and servicing particularly where a person can fall more than 2,0 m.

- Stability of lifting devices on soft ground, uneven surfaces and slopes must be considered. Cranes must be either anchored to the ground or to a foundation, or suitably counterweighted or stabilized to prevent overturning.

- Rail mounted cranes to have a track laid and secured on a firm foundation to prevent risk of derailment. There must be provision for buffers, effective braking systems, and adequate maintenance of both track and equipment.

- Measures must be taken to prevent a freely suspended load moving uncontrollably. Devices that could be fitted include multiple ropes.

- Cranes must be erected under planned conditions and the supervision of a competent person.

- If the operator cannot see the whole passage of a lift, an efficient signaling system must be used. A signaler must be capable of giving clear and distinct communications by hand. mechanical or electrical means.

- Testing examination and inspections are required for all equipment. Chains, slings, ropes, hooks, shackles, eyebolts, and other small components are no less important than grabs and winches. All must be tested and thoroughly examined before being put into operation.

- All cranes are clearly marked with their safe maximum working loads relevant lifting radius and maximum operating radius particularly when fitted with a derricking jib. Lifting equipment not designed for personnel must be clearly marked as such.

- Jib cranes to be fitted with an automatic safe load indicator such as a warning; light for the operator and a warning bell for persons nearby.

- Except for testing purposes, the safe working load must not be exceeded. - When loads are approaching the safe maximum load, the initial lift should be short. A

check should then be made to establish safety and stability before proceeding to complete the lift.


124

6.10. EXAMPLE WORKING DRAWINGS Plan Axes Sc. 1:200

C

A

41 2 3 5 6

B


125

Cross Section Warehouse Plan Sc. 1:100

12

+12.85

1,9

0,4

0,3

0,6

11,6

5

0,5

SM40*55

0,4

0,4

0,61,

15

C

2

-0.200,

10,

10,

1

0.00

GRP 9-125

0,55

0,44 EA 1.5x12

1,05

GPT 12-4

SC55*60

B

0,1

1.25 +9.45

+10.7

+12.4

11.35


126

Detail Plan Erection Procedure for Columns Sc.: 1:200

A

B

41 2 3

M7

S10

S2

M6

S9

S4

5 6

M5

S8 S7

S6

M4

C

S1

M1 M2 M3

S3 S5


127

Bay Detail Column Erection Sc.: 1:50

12S2

12M1

S1


128

Cross Section Erection Fazes Columns Sc. 1:100

0,61,

15

0,40

,50,

4

4,3

3,13

19,2

3

16,1

11,6

5

12,8

III

4,3

1

-0.20

II +9.45

11.35

12

612

7,5

2

2


129

Detail Plan Erection Procedure for Transverse Girder Beams Sc.: 1:200

B

12

24

M37,

5

6 6

56

1 2 3

Cra

ne ro

ute

12

4,56

A

12

7,56

G2

6

12

Trai

ler r

oute6

G4

G5

4 5 6

12 12

G7

G10

12

G12

M2M1

C

6 4,5

G1

GPT

6

T1

G3

G6

T2

G8

G9

G11

T3


130

Bay Detail Transverse Girder Beams Erection Sc.: 1:50

11,95

1212

G1

M1

Route trailer

T1prefabricat G3

G2

24


131

Cross Section Erection Transverse Girder Beams Sc. 1:100

10.95

16.1

9

I0.

5

IIIII

2.89

1212


132

Detail Plan Erection Procedure for Roof Slab Sc.: 1:200

12

24

T36

11,0

2

T29T15

11,0

2

M20T17M8

11,0

2

T3

A

B

12

M18M6

1

12

2 3

12

56

12

traseu macara

M3

M5

M4

M2

M1

M15T12

T11

T9T10

M17

M16

T6

T7T8

M7T5

T4

M14

T13T14

T15T16

M13

M30

4 5

12

6

12

M25

M28

M27

M29

M26

T24

T23

T22T21

T18

T20T19

T16

T17 M19

T26T25

T28T27

T44

T43T42

T39

T41T40

T37

T38

C GR

EA6

EA5

EA4

EA3

EA2

EA1

T22

T1M9

T2

M10

T20

T18

T19

T21

M12

M11T33

T13T14

M21

M22

T31

T30

T19

T32

M24

M23

T34T35


133

Bay Detail Roof Slab Erection Sc.: 1:50

Route trailer

T2

T1

T4

T5

T6

T3

R10=7.85

M3

12 R2=10

.021

1,23

M2

M1

traseu macara

EA5

EA6

5,24

R9=8.023

R8=9.5

23

R7=11

.023

R6=8.023

R5=9.5

23

R4=11

.023

R3=8.52

3,56

1,5EA1GR

EA2

EA3

EA4

R1=10

.181

4


134

Cross Section Erection Fazes Roof Slabs Sc. 1:100

12

10.95

BC

16.1

9

12

I0.

5

II

A

III

2.89


135

REFERENCES 6-1 Andres C., Smith R., Principles and Practices of Heavy Construction. Prentice Hall, USA, 1998. 6-2 Commonwealth of Kentucky Transportation Cabinet, Department of Highways. Division of Materials

Frankfort Kentucky. Precast/Prestressed Concrete Manual, USA, 2002. 6-3 Domşa J., Vescan V., Moga A., Tehnologia lucrărilor de construcţii. Editura Institutului Politehnic Cluj-

Napoca, 1988. 6-4 Forster G.: Building organization and procedures. Longman Scientific and Technical, England, 1988. 6-5 Fulletron R.L.: Construction Technology . Level 1. Oxford University Press, 1980. 6-6 Ghibu M., Gheorghiu N., Otel A., Suman R., Tehnologii moderne. Editura Tehnică, 1989. 6-7 Gould F., Joyce N. Construction Project Management. Second Edition. Prentice Hall, 2003. 6-8 Ilinoiu G., Construction Engineering. Conspress, Bucharest 2003. 6-9 IPCT, Nomenclator de elemente prefabricate din beton armat si beton precomprimat, vol. 1, 1988. 6-10 Murphy R. W., Site engineering. Construction Press. Astros Printing Limited, 1983. 6-11 Popa R., Teodorescu M., Montarea elementelor prefabricate de beton armat, beton precomprimat si

metalice. ICB, 1992. 6-12 Popa R., Teodorescu M., Tehnologia lucrarilor de constructii. Ed. ICB, Bucuresti, 1984. 6-13 Suman R., Ghibu M., Gheorghiu N., Oara C., Otel A., Tehnologii moderne în construcţii. Editura Tehnică,

Bucureşti, 1988. 6-14 Suman R., Pop S., Execuţia lucrărilor de construcţii. Editura Tehnică Bucureşti, 1989. 6-15 Trelea A., Popa R., ş.a., Tehnologia construcţiilor.Vol.1. Editura Dacia, Cluj-Napoca, 1997. 6-16 STAS 6657/3-89. Concrete, reinforced concrete and prestressed concrete elements – procedures,

instrumentation and devices for characteristic geometry checks. 6-17 C 156-89. Handbook for the application of STAS 6657/3-89 prescriptions - Concrete, reinforced concrete

and prestressed concrete elements – procedures, instrumentation and devices for characteristic geometry checks.

6-18 P 119-83. Instructiuni tehnice pentru proiectarea, executarea si exploatarea cailor de rulare pe grinzi de beton armat.

6-19 Technical Specifications ECCON. 6-20 Technical Specifications BUMAR – LABEDY S.A. 6-21 Technical Specifications LIEBHERR-Werk Nenzing Gmbh. 6-22 Technical Specifications TELEMAC HTA.

ABBREVIATIONS AND SYMBOLS CONVERSION TABLE

mm millimeter m meter mm2 square millimeter m2 square meter m3 cubic meter kg kilogram t tone (1000 kg) no. number hr hour km kilometer l liter % per cent m/d man day

1 in = 25,4 mm (exact value) 0,1 daN/cm2 = 1 MPa = 1 N/mm2 1 kgf = 9,80665 N (exact value) 1 kgf m = 9,80665 N m = 9,80665 J 1 kgf s/m2 = 9,80665 Pa s 1 kgfm / s = 9,80665 W 1 kgf / cm2 = 0,980665 bar (exact value) 1 kgf / cm2 = 1 at = 0,980665 x 10 5 bar 1 kgf / m2 = 1 mm H2O = 0,0980665 mbar = 9,80665 Pa 1 Torr = 1,333224 mbar 1 bar = 9,8 N/cm2 = 0,098 N/mm2 = 9,8 x 102 daN 1 mm Hg = 1 Torr = 1,333224 mbar = 133,3224 Pa 1oC = (1oF-32)x5/9 1 CP = 0,735499 kW Newton (N) = kg m/s2 = kilograms x 9.80665 Pascal (Pa) = N/m2

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