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1.1 New Construction Techniques for Modern Housing Schemes New Construction Techniques for Modern Housing Schemes Asoka Perera Professor of Civil Engineering Department of Civil Engineering University of Moratuwa 1.2 New Construction Techniques for Modern Housing Schemes Background  Sri Lanka’s construction industry is yet to be benefited from technologies developed for housing  Small scale applications are visible but largely the construction technology is reinforced concrete, bricks, blocks and other traditional methods.  However many other countries have implemented new housing technologies and getting the benefits. For example Government of Thailand have decided to use pre-cast concrete methods to construct more than 500,000 housing units to solve the housing problem.  Similarly in India the use of new methods have increased.  Generally new methods are cost effective, fast, better appearance, better planned settlements and durable. OVERVIEW 1.3 New Construction Techniques for Modern Housing Schemes OVERVIEW 1.4 New Construction Techniques for Modern Housing Schemes OVERVIEW

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    1.1

    New Construction Techniques for M odern Housing Schemes

    New Construction

    Techniques for ModernHousing Schemes

    Asoka Perera

    Professor of Civil Engineering

    Department of Civil Engineering

    University of Moratuwa

    1.2

    New Construction Techniques for Modern Housing Schemes

    Background

    Sri Lankas construction industry is yet to bebenefited from technologies developed for housing

    Small scale applications are visible but largely theconstruction technology is reinforced concrete,bricks, blocks and other traditional methods.

    However many other countries have implementednew housing technologies and getting the benefits.For example Government of Thailand have decidedto use pre-cast concrete methods to constructmore than 500,000 housing units to solve thehousing problem.

    Similarly in India the use of new methods haveincreased.

    Generally new methods are cost effective, fast,better appearance, better planned settlements anddurable.

    OVERVIEW

    1.3

    New Construction Techniques for M odern Housing Schemes

    OVERVIEW

    1.4

    New Construction Techniques for Modern Housing Schemes

    OVERVIEW

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    1.5

    New Construction Techniques for M odern Housing Schemes

    OVERVIEW

    1.6

    New Construction Techniques for Modern Housing Schemes

    OVERVIEW

    1.7

    New Construction Techniques for M odern Housing Schemes

    OVERVIEW

    1.8

    New Construction Techniques for Modern Housing Schemes

    OVERVIEW

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    1.9

    New Construction Techniques for M odern Housing Schemes

    The main pitfall Many believe alternative materials or methods is

    the way to reduce cost or to increase speedcompletely forgetting the design aspects.

    The design aspects are very poorly addressed orcompletely ignored due to the fact thatArchitects, Structural Engineers and ServiceEngineers need to work as a team. Howevermain cost savings are in the area of design.

    It is no doubt that new materials and methodscan be cost effective on top of the designaspects. Further alternative materials andmethods can address some pressing problemssuch shortage of river, shortage of skilled labour(or high cost) etc.

    HOUSING TECHNOLOGIES :OVERVIEW

    1.10

    New Construction Techniques for Modern Housing Schemes

    Three methods

    Design methods, optimization programs etc.Structural Design optimization is a goodexample.

    Alternative construction materials. Materials

    such compressed earth blocks, fly ash blocksare good examples.

    New construction methods. New slabconstruction methods, Pre-cast concrete

    methods, Ferrocement methods

    HOUSING TECHNOLOGIES :OVERVIEW

    1.11

    New Construction Techniques for M odern Housing Schemes

    HOUSING TECHNOLOGIES :OVERVIEW

    Tec hnology P ossible Cost

    savings

    Implementation Challenges

    1. D esign

    methods

    Structural Design

    Services design

    such as

    electrical,

    plumbing

    Architectural

    Design

    Up to 30% savings

    Up to 20% savings

    Up to 20% savings

    1. More design work

    2. No additional fee, in fact the fee could get

    reduced

    3. Lack of confidence

    4. Lack of familiarity with design methods such as

    masonry design.

    5. Naturally would like to be extra safe

    6. Bill is paid by the client

    7. No mechanism to check or to challenge the

    efficiency of the design. Very common system

    character

    8. May require the use of advance methods such as

    value analysis A technique use USA military.

    9. Getting and compiling technical information is

    difficult.

    10. Most popular may not the best.

    11. Similar reasons of structural design.

    12. Most difficult area for cost applications.

    13. People buy Maruti cars as well as Benz cars

    1.12

    New Construction Techniques for Modern Housing Schemes

    HOUSING TECHNOLOGIES :OVERVIEW

    Technology Possible Cost

    savings

    Implementation Challenges

    1.Alternative Construction

    Materials

    Compressed Earth Blocks(CEB)

    Waste related products such

    as fly ash blocks

    UPVC

    Cement tiles

    Up to maximum of

    20% cost savings.

    Generally claimedas cost effective or

    appear to be cost

    effective but not

    necessarily.

    1.Compliance with existing standards.

    Fore example CEB to comply with

    BS5628.

    2.Lack or non-existence of standardsparticularly for manufacture.

    3.General resistance to new materials.

    4.Lack of knowledge / information on

    the new material.

    1.New Construction

    methods

    Ex. Pre-cast concrete panels

    New floor systems

    Interlocking blocks

    Rat-Trap Bond method

    Up to a maximum of

    20%

    1. Similar to new materials

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    1.13

    New Construction Techniques for M odern Housing Schemes

    Three methods

    Most cost effective design method. For

    example a masonry design could be 30% costeffective than reinforced concrete framearrangement. On the other hand for a buildingof 8 storeys reinforced concrete frame buildingcould be more cost effective than a masonrydesign.

    Cost optimization within a design. Costoptimization can be done to find out the mosteconomical steel and section arrangementconsidering the prices of concrete, steel andformwork.

    Use of value analysis for design of servicessuch as electrical work, plumbing etc.

    HOUSING TECHNOLOGIES :DESIGN METHODS

    1.14

    New Construction Techniques for Modern Housing Schemes

    Most Cost effective Design method

    This could explain best with anexample. For example any house of twostorey and above can be taken. Theexample was taken form Tsunamihousing project in Ratmalana. Eachblock is consist of 8housing units andfour storeys

    HOUSING TECHNOLOGIES :DESIGN METHODS

    1.15

    New Construction Techniques for M odern Housing Schemes

    HOUSING TECHNOLOGIES :DESIGN METHODS

    1.16

    New Construction Techniques for Modern Housing Schemes

    HOUSING TECHNOLOGIES :DESIGN METHODS

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    1.17

    New Construction Techniques for M odern Housing Schemes

    Most Cost effective Design method

    The initial arrangement was typicalreinforced concrete frame buildingswith independent footings with plinthbeams, columns, beams and slabs.Table below shows the arrangementcost comparisons with masonry loadbearing wall structure.

    HOUSING TECHNOLOGIES :DESIGN METHODS

    1.18

    New Construction Techniques for Modern Housing Schemes

    HOUSING TECHNOLOGIES :DESIGN METHODS

    Element

    Normal RC Design Masonry Design

    Total Cost Total Cost

    Footings in foundations 346,546.0 217,338.0

    Plinth Beams 104,591.0 71,884.0

    Rubble masonry infoundation 79,650.0 223,680.0

    Columns 467,265.0 84,460.0

    Beams 759,133.0 0.0

    Walls 1,040,480.0 1,075,480.0

    TOTAL 2,797,665.0 1,672,842.0

    Net Saving 1,124,823.0

    Saving % 40.2%

    Net saving of the project 53,991,504.0

    Total Estimate 429,600,000.0

    Saving of the project % 12.6%

    1.19

    New Construction Techniques for M odern Housing Schemes

    Elemental optimum Design :Example froma RC slab

    Slab also an expensive element in buildings.The optimum slab thickness is the one justsatisfies the deflection requirement and bestreinforcement arrangement is the one justsatisfies the bar spacing requirement (crackcontrol). However when spans becomes larger

    the strength requirements supersedes theabove requirements.

    HOUSING TECHNOLOGIES :DESIGN METHODS

    1.20

    New Construction Techniques for Modern Housing Schemes

    Elemental optimum Design :Examplefrom a RC slab

    HOUSING TECHNOLOGIES :DESIGN METHODS

    Normal RC Design Optimum DesignTotal Cost Total Cost

    Slab - Concrete 248,500.0 248,500.0

    Slab - Reinforcement 264,504.0 186,960.0

    Slab - Formwork 203,550.0 203,550.0

    TOTAL 716,554.0 639,010.0

    Saving 77,544.0

    Saving % 10.8%

    Total project cost saving 3,722,112.0

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    1.21

    New Construction Techniques for M odern Housing Schemes

    Earth Related Technologies

    Compressed Stabilized Earth blocks

    Adobe Blocks

    Rammed Earth

    Other new methods

    Straw bale method

    Bamboo related methods

    Waste related methods

    Interlocking blocks

    Concrete blocks

    Polystyrene interlocking blocks

    ALTERNATIVE CONSTRUCTION MATERIALS

    1.22

    New Construction Techniques for Modern Housing Schemes

    The use of compressed earth blocks inSri Lanka

    First attempt in 1960s with CINVA rammachines

    Some houses were constructed in Colombo,Batticaloa etc.

    Second attempt in 1980s NBRO building,

    some in Gampaha

    In 1990s by University of Moratuwa morethan 2000 houses.

    There is growth of the application

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.23

    New Construction Techniques for M odern Housing Schemes

    The use of compressed earth blocks in SriLanka

    There are three manufacturers now.

    One well established and have fairly good demand.The start was very difficult and project in Horanahelped to get established.

    One has just commenced the production usingHydraform machine a good machine but blocksseem expensive

    One in Galle planning to introduce plain blocks aswell as interlocking blocks using Hydraformmachine.

    Some NGOs

    Small scale manufacturers

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.24

    New Construction Techniques for Modern Housing Schemes

    The use of compressed earth blocks inother countries

    India, There is wide usage mainly in Kerala,

    Tamil Nadu and other places Thailand Initiatives of Habitec Centre

    Australia

    USA

    Germany

    France

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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    New Construction Techniques for M odern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.26

    New Construction Techniques for Modern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.27

    New Construction Techniques for M odern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.28

    New Construction Techniques for Modern Housing Schemes

    SOIL BLOCK MACHINES

    Soil:cement block machine Nature of projects Cost of Machine

    1. CINVA ram machine

    This is a very simple machine. Can be

    transported from one project to the

    other very easily. However

    machine breaks quite often.

    Suitable for self-help rural projects.

    Good blocks can be made with

    good quality controlling

    measures

    Rs. 15,000 (Normal

    block)

    Rs. 35,000

    (Interlocking

    block)

    1. Auram Machines

    Very good manual machines

    manufactured in India. Two sizes

    of machines are available. Moulds

    are available to manufacture normal

    blocks and interlocking blocks

    Suitable to general building projects.

    Machine ideal for setting-up of

    small-scale block manufacturing

    yards too. The small machine

    very suitable for the construction

    of rural buildings

    Rs. 170,000 (with all

    optionsthree

    sizes of blocks)

    Rs. 90,000 (small

    machine)

    3.0 Automated hydraulic machines Large scale building projects and

    setting-up of block

    manufacturing yards

    Rs. 2.0 million

    Medium

    machines

    Rs. 12 to 50 million

    large machines

    form USA and

    China

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    New Construction Techniques for M odern Housing Schemes

    SOIL BLOCK MACHINES

    1.30

    New Construction Techniques for Modern Housing Schemes

    SOIL BLOCK MACHINES

    1.31

    New Construction Techniques for M odern Housing Schemes

    SOIL BLOCK MACHINES

    1.32

    New Construction Techniques for Modern Housing Schemes

    SOIL BLOCK MACHINES

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    New Construction Techniques for M odern Housing Schemes

    SOIL BLOCK MACHINES

    1.34

    New Construction Techniques for Modern Housing Schemes

    SOIL BLOCK MACHINES

    1.35

    New Construction Techniques for M odern Housing Schemes

    Standards for Earth Construction

    Sri Lanka now has a standard forCompressed StablizedEarth Blocks

    The use of provisions given in BS5628Standard for masonry, this will cover wall

    construction but not the manufacture ofearth blocks but does not cover themanufacture of blocks

    There is an Australian code of practice

    There is an appendix to the building code ofUSA

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.36

    New Construction Techniques for Modern Housing Schemes

    The Indian for manufacture ofcompressed earth blocks

    Specify the sizes of blocks, 300X140X100,

    240X240X100, 250X110X100 Specify the compressive strength expected

    from blocks, 2.5N/mm2 to 5.0N/mm2

    General statements on machines for block

    manufacture

    General statements on manufacturingprocess

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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    1.37

    New Construction Techniques for M odern Housing Schemes

    The use of provisions in BS5628

    Full scale wall panels and blocks need to be

    tested. Results were observed at

    Load deformation behaviour of wall panels;

    Stress at 1st crack; and

    Stress at failure

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.38

    New Construction Techniques for Modern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    Physical characteristics Specified limits

    Dry density

    Total water absorption

    >1750 kg/m3

    < 1 5 %

    Dry compressive strength

    Grade1: > 6 .0N/mm2

    Grade2 : >4.0up to6.0N/mm2

    Grade3 : 2.8 upto4.0N/mm2

    (not applicable for interlocking blocks)

    Wet compressive strength

    Grade1: >2 .4N/mm2

    Grade2 : >1.6up to2.4N/mm2

    Grade3 : >1.2up to1.6N/mm2

    (notapplicable for interlocking blocks)

    Flexural strength (bending strength) > 0.5 N/mm2

    Pitting depth (Erosion resistance)< 10 mm

    Linear expansion of block upon saturation with water< 0.10%

    1.39

    New Construction Techniques for M odern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.40

    New Construction Techniques for Modern Housing Schemes

    The Australian code of practice

    It is available in the CD given

    Let us go through the code

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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    1.41

    New Construction Techniques for M odern Housing Schemes

    Manufacture of Soil cement blocks

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.Extraction of soil; 2 . Transportation of soil;

    3.Screening of soil; 3. Measuring of soil and

    cement;

    4. Dry mixing of soil and

    cement;

    5. Adding of water for humid

    mixing;

    6. Moulding using a

    machine;

    7. Curing of soil:cement

    blocks; and

    8. Storing of blocks.

    1.42

    New Construction Techniques for Modern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.43

    New Construction Techniques for M odern Housing Schemes

    We could use

    SLS StandardsSLS1382

    Machine manufacturers manuals

    Published manuals a good one in the CD Let us go through a good manual

    Published by GATE

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.44

    New Construction Techniques for Modern Housing Schemes

    Block Types

    Different types are available

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.50

    New Construction Techniques for Modern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.51

    New Construction Techniques for M odern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.52

    New Construction Techniques for Modern Housing Schemes

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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    1.57

    New Construction Techniques for M odern Housing Schemes

    Rammed Earth method

    Houses can be constructed with full

    rammed earth methods It is much easier to first erect concrete

    columns and then to rammed earth wall

    using slip form method

    Probably the best may be to first erectreinforced earth columns using interlockingblocks and then to do the rammed earth

    walls

    Forms could be purchased fromgovernment factory and private suppliers

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.58

    New Construction Techniques for Modern Housing Schemes

    Rammed Earth method

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.59

    New Construction Techniques for M odern Housing Schemes

    Rammed Earth method

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.60

    New Construction Techniques for Modern Housing Schemes

    Rammed Earth method

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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    1.61

    New Construction Techniques for M odern Housing Schemes

    Rammed Earth method

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.62

    New Construction Techniques for Modern Housing Schemes

    Rammed Earth method

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.63

    New Construction Techniques for M odern Housing Schemes

    Rammed Earth method

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

    1.64

    New Construction Techniques for Modern Housing Schemes

    Rammed Earth method

    ALTERNATIVE CONSTRUCTION MATERIALS :EARTH CONSTRUCTIONS

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    1.65

    New Construction Techniques for M odern Housing Schemes

    Very widely used in India

    This is basically brick on edge

    ALTERNATIVE CONSTRUCTION M ETHODS : RAT-TRAP BOND METHOD

    1.66

    New Construction Techniques for Modern Housing Schemes

    Very widely used in India

    This is basically brick on edge

    ALTERNATIVE CONSTRUCTION METHODS : RAT-TRAP BOND METHOD

    1.67

    New Construction Techniques for M odern Housing Schemes

    Wide range of floor slabs are nowavailable for housing

    In Sri Lanka ICC, NERD, University of

    Moratuwa Habitech centre has curved plans and

    integrated concrete slab

    ALTERNATIVE CONSTRUCTION METHODS :FLOOR SLABS

    1.68

    New Construction Techniques for Modern Housing Schemes

    ALTERNATIVE CONSTRUCTION METHODS :FLOOR SLABS

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    New Construction Techniques for M odern Housing Schemes

    Pre-cast concrete door and windowframes

    Roof items Pre-cast purlins Steel roof structures for housing you

    will get more details during site visits

    Steel forms for staircases

    There are many more from Habiteccentre

    ALTERNATIVE CONSTRUCTION M ETHODS :OTHER METHODS

    1.70

    New Construction Techniques for Modern Housing Schemes

    Formwork systems for concrete wallsand slabs

    Polystyrene forms for walls Sprayed concrete on polystyrene

    boards

    Wide range of products are available forabove methods

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

    1.71

    New Construction Techniques for M odern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are availablefrom Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

    1.72

    New Construction Techniques for Modern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are availablefrom Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

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    1.73

    New Construction Techniques for M odern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are available

    from Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

    1.74

    New Construction Techniques for Modern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are available

    from Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

    1.75

    New Construction Techniques for M odern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are availablefrom Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

    1.76

    New Construction Techniques for Modern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are availablefrom Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

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    New Construction Techniques for M odern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are available

    from Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

    1.78

    New Construction Techniques for Modern Housing Schemes

    Formwork system MASCON fromCanada Similar systems are available

    from Germany, India etc.

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

    1.79

    New Construction Techniques for M odern Housing Schemes

    Polystyrene forms for walls availableform USA, Australia etc.

    Generally expensive

    ALTERNATIVE NEW CONSTRUCTION M ETHODS

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    New Construction Techniques for Modern Housing Schemes

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    New Construction Techniques for M odern Housing Schemes

    1.82

    New Construction Techniques for Modern Housing Schemes

    1.83

    New Construction Techniques for M odern Housing Schemes

    Let us look at compressed earth blocks

    PROCUREMENT OF TECHNOLOGY AND COST SAVINGS

    1.84

    New Construction Techniques for Modern Housing Schemes

    Design methods

    Alternative construction materials

    Alternative construction methods

    Cost of setting out

    SUMMARY

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    New Construction Techniques for M odern Housing Schemes

    THANK YOU