as 3735-2001 concrete structures retaining liquids

LICENCE for

Licensee:

Date:

Conditions of use:

WEB LINKS

Check if this document is current

Find similar documents

StandardsWatch (info and login)

Visit our website

International Standards on-line at www.standards.com.au

Click here for full conditions of Licence

AS 37352001

Australian Standard

Concrete structures for retaining liquids

AS 3735

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

This Australian Standard was prepared by Committee CE-022, Concrete Structuresfor Retaining Liquids. It was approved on behalf of the Council of StandardsAustralia on 17 November 2000 and published on 13 March 2001.

The following interests are represented on Committee CE-022:Australian Pre-mixed Concrete AssociationInstitution of Engineers AustraliaUniversity of QueenslandWater Services Association of Australia

Additional interests participating in the preparation of this Standard:Association of Consulting Engineers AustraliaAustralian Chamber of Commerce and IndustryAustralian Post Tensioning AssociationAustralian Water and Wastewater AssociationBrisbane City CouncilDepartment of Public Works and Services N.S.W.Melbourne WaterNational Precast Concrete Association AustraliaNSW Department of Land and Water ConservationSwimming Pool and Spa Association of N.S.W.Sydney Water CorporationUniversity of New South WalesWater Corporation Western Australia

Keeping Standards up-to-dateStandards are living documents which reflect progress in science, technology andsystems. To maintain their currency, all Standards are periodically reviewed, andnew editions are published. Between editions, amendments may be issued.Standards may also be withdrawn. It is important that readers assure themselvesthey are using a current Standard, which should include any amendments whichmay have been published since the Standard was purchased.Detailed information about Standards can be found by visiting the StandardsAustralia web site at www.standards.com.au and looking up the relevant Standardin the on-line catalogue.Alternatively, the printed Catalogue provides information current at 1 January eachyear, and the monthly magazine, The Australian Standard, has a full listing ofrevisions and amendments published each month.We also welcome suggestions for improvement in our Standards, and especiallyencourage readers to notify us immediately of any apparent inaccuracies orambiguities. Contact us via email at [email protected], or write to the ChiefExecutive, Standards Australia International Ltd, GPO Box 5420, Sydney,NSW 2001.

This Standard was issued in draft form for comment as DR 99305.Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001

Australian Standard

Concrete structures for retaining liquids

Originated as AS 37351991.Second edition 2001.

COPYRIGHT Standards Australia InternationalAll rights are reserved. No part of this work may be reproduced or copied in any form or by anymeans, electronic or mechanical, including photocopying, without the written permission of thepublisher.Published by Standards Australia International LtdGPO Box 5420, Sydney, NSW 2001, AustraliaISBN 0 7337 3714 5

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001 2

PREFACEThis Standard was prepared by the Standards Australia Committee CE-022, ConcreteStructures for Retaining Liquids, to supersede AS 37351991.The objective of this standard is to provide designers of reinforced concrete structures usedfor retaining liquids at ambient temperatures with specifications for design and installation.

For structures that specifically relate to concrete structures used for retaining liquids atambient temperature, this Standard supplements and takes precedence over the requirementsof AS 3600, Concrete structures.Statements expressed in mandatory terms in notes to tables are deemed to be requirementsof this Standard.This draft Standard has been prepared from the previous edition of AS 37351991. TheStandard is limited to concrete with a concrete stress limited in the range of 20 MPa to50 MPa at 28 days.A Commentary, published as Supplement No. 1 to AS 3735, provides backgroundinformation and explanation on the application of this Standard.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 373520013

CONTENTS

Page

SECTION 1 SCOPE AND GENERAL1.1 SCOPE AND APPLICATION .....................................................................................41.2 REFERENCED DOCUMENTS ...................................................................................51.3 DEFINITIONS.............................................................................................................51.4 NOTATION .................................................................................................................51.5 USE OF ALTERNATIVE MATERIALS OR METHODS...........................................61.6 DRAWINGS AND SPECIFICATIONS .......................................................................7

SECTION 2 LOADS AND LOAD COMBINATIONS2.1 GENERAL...................................................................................................................82.2 LOADS AND OTHER ACTIONS ...............................................................................82.3 STABILITY DESIGN................................................................................................ 102.4 LOAD COMBINATIONS FOR SERVICEABILITY ................................................ 10

SECTION 3 DESIGN FOR SERVICEABILITY AND STRENGTH3.1 GENERAL................................................................................................................. 113.2 REINFORCED CONCRETE ..................................................................................... 113.3 PRESTRESSED CONCRETE.................................................................................... 13

SECTION 4 DESIGN FOR DURABILITY4.1 GENERAL................................................................................................................. 154.2 EXPOSURE CLASSIFICATION............................................................................... 154.3 REQUIREMENTS FOR CONCRETE ....................................................................... 164.4 REQUIREMENTS FOR COVER TO REINFORCEMENT

(BARS AND TENDONS).......................................................................................... 164.5 DURABILITY OF METAL FIXTURES IN CONTACT WITH CONCRETE........... 184.6 DURABILITY OF WATERSTOPS, SEALANTS AND OTHER

ASSOCIATED ITEMS .............................................................................................. 18

SECTION 5 MATERIAL AND CONSTRUCTION REQUIREMENTS5.1 GENERAL................................................................................................................. 195.2 CONCRETE............................................................................................................... 195.3 REINFORCEMENT................................................................................................... 19

SECTION 6 JOINTS, WATERSTOPS, JOINT FILLERS, AND SEALANTS6.1 JOINTS ...................................................................................................................... 206.2 WATERSTOPS.......................................................................................................... 216.3 JOINT FILLERS........................................................................................................ 216.4 SEALANTS ............................................................................................................... 216.5 CONTAMINATION OF WATER ............................................................................. 21

SECTION 7 TESTING7.1 GENERAL................................................................................................................. 227.2 TESTING FOR LIQUID-TIGHTNESS...................................................................... 227.3 TESTING OF LIQUID-RETAINING STRUCTURES............................................... 227.4 TESTING OF ROOFS ............................................................................................... 22

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001

Standards Australia www.standards.com.au

4

STANDARDS AUSTRALIA

Australian StandardConcrete structures for retaining liquids

S E C T I O N 1 S C O P E A N D G E N E R A L

1.1 SCOPE AND APPLICATION1.1.1 ScopeThis Standard specifies requirements for concrete structures and members that includereinforcing steel or tendons, or both, used for retaining liquids at ambient temperature.The Standard supplements and takes precedence over the requirements of AS 3600.The principles of concrete design and construction embodied in this Standard apply tostructures and members made of concrete(a) with a characteristic compressive strength at 28 days (f c) in the range of 20 MPa to

50 MPa; and(b) of saturated, surface-dry density in the range of 1800 kg/m3 to 2800 kg/m3.The Standard does not apply to the design of

(i) dams;(ii) aqueducts, hydraulic tunnels or similar structures;(iii) small septic tanks (see AS 1546.1);(iv) portable precast concrete water tanks of less than 25 000 L capacity;(v) fibre-impregnated concrete that does not comply with the design requirements and

procedures of AS 3600; or(vi) precast concrete pipes (pressure and non-pressure) (see AS 4058).1.1.2 ApplicationThis Standard applies to concrete structures for the storage of liquids where the exposureconditions for concrete are within the specified limits. Such structures include thoseretaining water or sewage, public swimming pools, and swimming pools the area or overalllength of which are greater than that specified in AS 2783. However, where applicable, thespecifications of the relevant authority shall be used.

NOTE: It is intended that the design of a structure or member to which this Standard applies, becarried out by, or under the supervision of, an engineer as defined in Clause 1.6.2.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001

www.standards.com.au Standards Australia

5

1.2 REFERENCED DOCUMENTSThe following documents are referred to in this Standard:AS1012 Methods of testing concrete1012.13 Part 13: Determination of drying shrinkage of concrete for samples prepared

in the field or in the laboratory1170 Minimum design loads on structures1170.1 Part 1: Dead and live loads and load combinations1170.2 Part 2: Wind loads1170.4 Part 4: Earthquake loads1379 Specification and supply of concrete3582 Supplementary cementitious materials for use with portland (and blended)

cement3582.1 Part 1: Fly-ash3582.2 Part 2: SlagGround granulated iron blast-furnace3582.3 Part 3: Silica fumeAS/NZS1546 On-site domestic waste water treatment units1546.1 Part 1: Septic tanks2783 Use of reinforced concrete for small swimming pools2841 Galvanized steel wire strand3600 Concrete structures3610 Formwork for concrete3735 Concrete structures for retaining liquidsCommentary4058 Precast concrete pipes (pressure and non-pressure)4680 Hot-dipped galvanised (zinc) coatings on fabricated ferrous articlesHB79 Alkali Aggregate reactionGuidelines on minimising the damage to concrete

structures in AustraliaNZS3106 Code of practice for concrete structures for the storage of liquidsASTMA 775M Specification for epoxy-coated reinforcing steel bars

1.3 DEFINITIONSFor the purpose of this Standard, the definitions given in AS 3600 apply.

1.4 NOTATIONUnless a contrary intention appears the following applies:

(a) The symbols used in this Standard shall have the meanings ascribed to them below,with respect to the structure, or member, or condition to which a clause is applied.

(b) Where non-dimensional ratios are involved, both the numerator and denominator areexpressed in identical units.

(c) The dimensional units for length, force and stress in all expressions or equations areto be taken as millimetres (mm), Newtons (N) and megapascals (MPa) respectively.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


6

Quantitysymbol

Definition

Ac, eff = effective concrete area (see Figure 3.1)As = the cross-sectional area of reinforcementa1, a2 = a distance (see Figure 3.1)D = the overall depth of a cross-section in the plane of bendingdb = the nominal diameter of a bar, wire, or tendonFep = the earth pressure loadFeq = the earthquake action calculated in accordance with Appendix A of

AS 3600Flp = the liquid pressure loadFsh = the loads, or their related moments and forces, resulting from shrinkageFsw = the loads, or their related moments and forces, resulting from swellingfcp = the compressive strength of concrete at transferfs = the tensile stress in non-tensioned reinforcing steelfso = the nominal limiting tensile stress in reinforcing steelfsy = the yield strength of the reinforcing steelf c = the characteristic compressive cylinder strength of concrete at 28 daysf s max. = the effective limiting tensile stress in reinforcing steelfct.3 = the direct tensile strength of the concrete at 3 daysG = the dead loadP = the force in the tendons; or

= the maximum force in the anchoragep = a reinforcement ratioQ = the live load (including impact, if any)T = temperature; or

= the load due to temperature variationW = the wind load calculated, in accordance with AS 1170.2, from a wind

velocity with the appropriate return periodY1, Y2, Y3 = exposure coefficientss = increase in tendon stress once decompression occurs in a partially

prestressed membersh = a shrinkage strainsw = a swelling strain

1.5 USE OF ALTERNATIVE MATERIALS OR METHODS1.5.1 GeneralProvided that the requirements of AS 3600 are met, this Standard shall not be interpreted soas to prevent the use of materials or methods of design or construction not specificallyreferred to herein.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


7

1.5.2 Existing structuresWhere the strength or serviceability of an existing structure is to be evaluated, theprinciples of this Standard and AS 3600 may be applied.1.5.3 Ferrocement1.5.3.1 GeneralFerrocement shall be thin-walled, reinforced cement mortar construction in which thereinforcement comprises closely spaced layers of straight wire mesh from 1 mm to 6 mmdiameter and in which the cement mortar is pneumatically placed or plastered in layers.

NOTE: Other arrangements of ferrocement are not covered by this Standard.

1.5.3.2 MaterialThe material requirements for ferrocement shall be as specified in NZS 3106.

1.6 DRAWINGS AND SPECIFICATIONS1.6.1 Design dataThe following design data shall be shown in the drawings:(a) Reference number and date of issue of applicable design Standards.(b) Live loads used in design.(c) Exposure classification for durability.(d) Fire resistance level, if applicable.(e) Class and, where appropriate, grade designation of concrete.(f) Grade and type of reinforcement and tendons.1.6.2 Design detailsThe drawings or specification for concrete members and structures should include, asappropriate, the following:

(a) The shape and size of each member.(b) The finish and method of control for unformed surfaces.(c) Class of formwork for the surface finish specified in accordance with AS 3610.(d) The size, quantity and location of all reinforcement, tendons and structural fixings

and the minimum cover to each.(e) The requirements for concrete (see Clause 4.3).(f) The curing procedure and duration.(g) The force required in each tendon, the maximum jacking force to be applied and the

order in which tendons are to be stressed.(h) The location and details of planned construction or movement joints, connections and

splices, and the method to be used for their protection.(i) The minimum period of time before stripping of forms and removal of shores.(j) Any constraint on construction assumed in the design.(k) Any special protective coatings.(l) Other design requirements.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


8

S E C T I O N 2 L O A D S A N D L O A DC O M B I N A T I O N S

2.1 GENERALThe design of structures and members for stability, strength and serviceability shall takeaccount of the load and load combinations for strength in accordance with AS 3600 and ofthe action effects directly arising from the loads and other actions included in this Section.

2.2 LOADS AND OTHER ACTIONS2.2.1 TemperatureThe walls and roofs of tanks shall be designed for the action effect arising from differentialtemperature gradients through the member.For tanks containing liquids at ambient temperature and subject to direct solar radiation, thedesign temperature gradients considered shall include the following cases:(a) For roofs

(i) a 20C variation from the mean temperature; and(ii) the temperature criteria given in Table 2.1.

(b) For walls(i) when the tank is filled with liquid, by a +30, 20C variation; and(ii) when the tank is empty, by a +20, 12C variation;

from the internal wall temperature as shown in Figure 2.1.NOTE: Temperature effects for liquids at other than ambient temperatures are not specified inthis Standard.

FIGURE 2.1 TEMPERATURE DISTRIBUTIONS IN TANK WALLS

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


9

TABLE 2.1ROOFTEMPERATURE CRITERIA

Region Linear temperature gradient, degreesCelsius per 100 mm of roof thickness

Snow (outside colder than inside) 10Other (outside hotter than inside) 5

2.2.2 Moisture variationIn the absence of a rational analysis of moisture variation, appropriate to the expectedconstruction/loading history for the structure, the minimum effects due to moisturevariation, either shrinkage or swelling, for both roofs and walls, shall be determined for thestrains as given in Table 2.2.

TABLE 2.2

MOISTURE VARIATIONSHRINKAGE AND SWELLING STRAINS

Mean shrinkage and swelling strain (creep adjusted)

106

Shrinkage (sh) Swelling (sw)Wall thicknessmmPrecast Cast in situ Precast Cast in situ

100 70 120 300 250

150 50 85 205 170

200 45 70 160 135250 35 60 135 110

2.2.3 EarthquakeLoads due to earthquakes shall be determined in accordance with AS 1170.4.

NOTE: NZS 3106 includes details for analysis of loads due to earthquakes.

2.2.4 Other actionsAny action that may significantly affect the stability, strength and serviceability ofstructures and members, including but not limited to the following, shall be taken intoaccount:

(a) Backfill.(b) Fatigue.(c) Progressive failure.(d) Ground movements.(e) Construction loads.(f) Liquid load.(g) Wind.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


10

2.3 STABILITY DESIGNIn addition to the mass of the empty structure, the design resistance against uplift may takeaccount of

(a) anchoring systems;(b) drainage systems;(c) pressure relief valves; or(d) any combination of Items (a), (b) and (c).The minimum safety factor against uplift shall be determined in accordance withAS 1170.1. The designer shall assess the effectiveness of the devices in Items (a) to (d).

2.4 LOAD COMBINATIONS FOR SERVICEABILITYThe design load for serviceability design shall be the appropriate combinations of factoredloads for long-term effects, Group A, and short-term effects, Group B, given below:(a) Long-term effects (Group A):

(i) Roof G + P + Fsh(ii) Wall

(A) Tank full: G + Flp + Fep + P + 0.5 Fsw(B) Tank empty: G + Fep + P + (Fsh or 0.5 Fsw)

(b) Short-term effects (Group B):(i) Roof

(A) G + Q + P + T(B) 0.8G + W + P(C) G + P + T + (0.7Fsh or 0.7Fsw)(D) 0.8G + 0.8Feq

(ii) Wall(A) Tank full: G + Flp + Fep + P + 0.8Feq + 0.5Fsw(B) Tank full: G + Flp + Fep + P + 0.7 Fsw + T(C) Tank empty: G + Fep + P + T + (0.7 Fsh or 0.35 Fsw)

In Items (a) and (b) above, the dead load (G) shall be taken as the mass of structuralmembers plus superimposed dead loads.If a worse effect is obtained by the omission of one or more of the transient loads inItem (a) or Item (b) above then such effect shall be taken into account.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


11

S E C T I O N 3 D E S I G N F O R S E R V I C E A B I L I T YA N D S T R E N G T H

3.1 GENERALAlthough design for serviceability will generally dominate, design for strength shall beconsidered to ensure that the load capacity and slenderness ratios for members of thestructure are within acceptable limits.

3.2 REINFORCED CONCRETE3.2.1 GeneralThe reinforcement ratio shall be calculated using the following equation:

effc,s / AAp = . . .3.2.1NOTE: a2 = 0.5D but not greater than 250 mm, except for the surface of a slab that is in contact with theground then not greater than 100 mm

FIGURE 3.1 EFFECTIVE CONCRETE AREA

3.2.2 Minimum reinforcement ratioA minimum reinforcement ratio shall be provided to limit cracking. This quantity isdependent on the degree of restraint afforded, as follows:(a) Unrestrained concrete The minimum reinforcement ratio for unrestrained concrete

shall be determined from the following equation:

sy

ct.3min. f

fp =

. . . 3.2.2

where

pmin. = the minimum reinforcement ratio

fct.3 = the principal tensile strength of concrete at three daysfsy = the yield strength of the reinforcementLic

ense

d to

Ishe

a A

Bedd

ing

on 1

1 Ja

n 20

05. 1

use

r per

sona

l use

r lice

nce

only.

Sto

rage

, dist

ribut

ion

or u

se o

n ne

twor

k pr

ohib

ited.

AS 37352001


12

(b) Restrained concrete The minimum reinforcement ratio for fully restrained concreteshall be as defined in Table 3.1.

Values given in Table 3.1 may be reduced in proportion to the degree of restraint. Thevalues may be reduced by 25% if(i) movement joints are provided at maximum 15 m spacing; or(ii) partial movement joints are provided at maximum 7.5 m spacing.

TABLE 3.1DEFORMED BARSPERCENTAGE FOR FULLY

RESTRAINED CONCRETE

db, mm 8-12 16 20 24 28 32

pmin. % 0.48 0.64 0.80 0.96 1.12 1.28

3.2.3 Limiting steel stresses for serviceabilityThe extent of cracking should be controlled by limiting the tensile stresses in thereinforcing steel, under the most severe combination of service loads. The value of suchstress shall be calculated from the following equation:

sofYYYf 321max. s = . . . 3.2.3The values of fso, Y1 Y2and Y3 are as given in Tables 3.2, 3.3, 3.4 and 3.5.When welded wire fabric is used, welded intersections shall not be further apart than200 mm.For members less than 225 mm thick, the face remote from the liquid shall be considered asthough it was in contact with the liquid

TABLE 3.2NOMINAL LIMITING STRESSES IN

STEEL REINFORCEMENT

db, mm 8-12 16 20 24 28-32

fso, MPa 150 140 130 120 110

TABLE 3.3COEFFICIENT FOR BAR TYPE Y1

Type of reinforcementExposure coefficient

Plain bar Deformed bar andwelded wire fabric

Y1 0.85 1.00

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


13

TABLE 3.4LOAD COMBINATION COEFFICIENT, Y2

Load combination Y2

Long term effects (Group A) 1.0Short term effects (Group B) 1.25

TABLE 3.5COEFFICIENT FOR STRESS STATE AND TYPE OF EXPOSURE Y3

Type of exposureExposure coefficient Predominant stress

state Continuouslysubmerged

Intermittent wettingand drying

Tension 1.00Y3

Flexure 1.251.00

3.2.4. Limiting concrete thicknessIn the hoop direction of a circular tank, the concrete is assumed to be fully cracked and thereinforcement is designed to take the full hoop force with no contribution from the concreteso that the concrete thickness is limited by the requirements for the placement ofreinforcement and concrete. Where other forces are involved, the concrete thickness islimited by the moment and shear capacity of the section.

3.3 PRESTRESSED CONCRETE3.3.1 GeneralAll prestressing tendons shall be bonded.3.3.2 AnalysisIn addition to the requirements of Section 2, the analysis shall take account of the fulleffects of prestressing including secondary effects and time-dependent creep effects.Analysis shall be carried out for the following load conditions and combinations:(a) Conditions at any stage of prestress.(b) Group A load combination that comprises predominantly long-term loads.(c) Group B load combination that includes the short-term transient loads.3.3.3 Limiting concrete stresses for serviceabilityExcept as permitted by Clause 3.3.5, stresses shall be calculated on the basis of uncrackedsections, and shall remain within the limits specified in Table 3.6.3.3.4 Non-tensioned reinforcementNon-tensioned reinforcement shall be provided in prestressed elements in(a) end anchorage zones; and(b) between end anchorages, where prestress is calculated to be inadequate to sustain

applied forces.Licen

sed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


14

TABLE 3.6LIMITING STRESSES IN PRESTRESSED CONCRETE

Load combination, MPaType of stress

Transfer Group A(long-term loads)Group B

(short-term loads)(a) Maximum compression 0.50fcp 0.40f c 0.55f c(b) Minimum compression at tendon

location 0.70 0

(Note 1)(c) Minimum compression at

construction joints 0.70 0

(Note 2)(d) Maximum extreme fibre tension in

monolithic concrete

(i) at water-retaining face 0.17 f cp0.70 0.5 f c

(ii) at non-water-retaining face(Note 3) 0.17 f cp 0.25 f c

0.5 f c

(e) Maximum principal tension resultingfrom shear 0.17 f cp 0.30 f c

0.5 f c

NOTES: 1 Where earthquake forces have been considered, a maximum tension of 0.5 f c is permissible.2 Cracking is permitted in joints under Group B combinations when non-tensioned reinforcement is

provided to carry the entire tension force across the joint. The force shall be calculated on the basis of anuncracked section and reinforcement stresses shall comply with the limits specified in Clause 3.2.3.

3 For members less than 225 mm thick, the face remote from the liquid shall be considered as though it wasin contact with the liquid.

3.3.5 Partial prestressingA partially prestressed design approach, permitting cracking of concrete, may be usedprovided the tensile stress in the non-tensioned reinforcement (fs), and the increase intendon stress once decompression occurs (s), taking full account of shrinkage and creepeffects, satisfy the following requirements:

(a) fs f s max.; and(b) s 100 MPa, for group A load combinations; or

s 125 MPa, for group B load combinations.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


15

S E C T I O N 4 D E S I G N F O R D U R A B I L I T Y

4.1 GENERALDurability shall be allowed for in design by determining the exposure classificationspecified in Clause 4.2 and, for that exposure classification, complying with the appropriaterequirements for the following:

(a) Concrete, in accordance with Clause 4.3.(b) Cover, in accordance with Clause 4.4.The exposure classification shall take into account suitable means of isolating the concretefrom the exposure environment.

4.2 EXPOSURE CLASSIFICATIONThe exposure classification for the surface of a member shall be determined from Table 4.1and from AS 3600 for the most severe environment or use to which the concrete will besubjected to during its operational life.

TABLE 4.1EXPOSURE CLASSIFICATIONS

Exposure classification

Predominantly submergedItem Characteristic of liquid in contact withconcrete surface

Generallyquiescent

Agitated orflowing

Alternate wet anddry (condensation

splashing orwashing)

1 Freshwater: (Notes 1, 2, 3)(a) I positive of pH >7.5(b) I negative & pH 6.5 to 7.5(c) I negative & pH 5.5 to 6.5

B1B1B2

B1B2C

B1B1B2

2 Sewage and waste water: (Note 4)(a) reshlow risk of H2S corrosion(b) talehigh risk of H2S corrosion (Note 8)(c) naerobic sludge

B1B2B1

B1B2B1

B2DB1

3 Sea water: (Notes 5, 6)(a) eneral immersion and pH 7.5(b) etaining or excluding situations or pH

AS 37352001


16

NOTES TO TABLE 4.1;1 An approximate value of Langelier Saturation Index (LI) may be obtained from the equation:

LI = pH of water pH when in equilibrium with calcium carbonate= pH 12.0 + log10[2.5 Ca2+ (mg/L) total alkalinity (as CaCO3 mg/L)].

(A negative value for LI means the water has a demand for CaCO3).2 For lower pH values see Item 4.3 For water containing significant quantities of aggressive dissolved materials see Item 5(b).4 Industrial sewage and waste water may contain aggressive chemicals. The designer shall refer

to other liquids as given in Table 4.1 (see also AS 3735 Supp1).5 The use of galvanized or epoxy-coated reinforcement or a waterproofing agent should be

considered. Details are given in AS 3735 Supp1.6 The use of sulfate-resisting cement is discouraged.7 Only applicable for submergence greater than 1 m below low water ordinary spring tide.8 Typical examples of severities are given in AS 3735 Supp1.9 The use of calcareous aggregate should be considered. Details are specified in AS 3735

Supp1.10 Guidance on the selection of an appropriate exposure classification from within the range

indicated is specified in AS 3735 Supp1.11 For members in contact with extracted ground water see Item 1 or 5.

4.3 REQUIREMENTS FOR CONCRETEThe concrete shall comply with the following:

(a) A minimum f c as given in(i) Table 4.2 for concrete where standard formwork and compaction are used; or(ii) Table 4.3 for concrete where rigid formwork and intense compaction are used

such as obtained with vibrating tables and form vibrators.(b) An average compressive strength at the completion of curing of not less than 75% of

the specified f c.(c) A cementitious material content of not less than 320 kg/m3.(d) A drying shrinkage strain at 56 d not greater than 700 106 determined in

accordance with AS 1012.13.(e) A total reactive alkali content not greater than 3.0 kg Na2O (equivalent) per cubic

metre, determined as outlined in HB 79.(f) The water/cement ratio should not exceed 0.50 for B2, C and D or 0.55 for B1

exposure classifications.NOTE: For thick members, the heat of hydration should be controlled to limit temperaturedifferentials during hydration.

4.4 REQUIREMENTS FOR COVER TO REINFORCEMENT (BARS AND TENDONS)4.4.1 GeneralThe cover for bars and tendons shall be the greatest of the values determined fromClauses 4.4.2 to 4.4.4, as appropriate.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


17

4.4.2 Cover for concrete placementFor concrete placement

(a) the cover and arrangement of the reinforcement shall be such that concrete can beproperly placed and compacted to comply with the material and constructionrequirements specified in AS 3600; and

(b) the cover shall be not less than either 1.5 times the maximum nominal aggregate size,or the nominal size of the bar or tendon to which the cover is measured.

4.4.3 Cover for corrosion protectionFor corrosion protection, the cover shall be not less than the appropriate value given inTables 4.2 and 4.3 and Clause 4.4.5.

TABLE 4.2

REQUIRED COVER WHERE STANDARD FORMWORK ANDCOMPACTION ARE USED

Required cover, mm

Characteristic strength (f c), MPa*Exposureclassification32 40 50

B1 45 40 40

B2 70 50 40C N/A (Note 1) 75 55

D (Note 1) N/A (Note 1) 75 55* See also Clause 4.4.4.

NOTES: 1 Concrete surface shall be isolated from the attacking environment.2 Protective coatings (see Clause 5.3) do not permit a reduction in the cover

requirement.

TABLE 4.3REQUIRED COVER WHERE RIGID FORMWORK AND

INTENSE COMPACTION ARE USED

Required cover, mm

Characteristic strength (f c), MPa*Exposureclassification32 40 50

B1 35 30 25

B2 55 40 30

C N/A (see Note) 60 45D N/A (see Note) 60 45

* See also Clause 4.4.4.NOTE: Concrete surface shall be isolated from the attackingenvironment.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


18

4.4.4 Cover modifications for special circumstances4.4.4.1 Cast against groundWhere concrete is cast on or against ground and compacted in accordance with the materialand construction requirements specified in AS 3600, the cover to a surface in contact withthe ground shall be as given in Table 4.2 but increased by

(a) 10 mm if the concrete surface is protected by a damp-proof membrane; or(b) 20 mm otherwise.4.4.4.2 Chemical or mechanical surface treatmentThe clear concrete cover shall be increased by the depth that will be degraded by thechemical or mechanical surface treatment. This shall include any layer where chemicaltreatment increases the chemical content above that specified in AS 3600. Chemicaltreatment shall not be permitted if the chemicals remaining in the additional cover couldpermeate into or attack the member.4.4.4.3 Formed upper surfacesThe clear concrete cover to upper surfaces (e.g. sloping surfaces) that are formed by usingimpermeable shutters shall be increased by 10 mm, unless special precautions are taken.4.4.4.4 Embedded items in cover zoneNo items, including tie wire, that could be corroded by the environment to which theconcrete will be subjected shall be embedded in the cover zone. Non-corrodible items suchas conduits or reinforcement chairs may be embedded in the cover zone provided(a) the cover required for concrete placement is maintained or exceeded;(b) an allowance is made for any reduction in strength; and(c) no path is created that will enable the surrounding environment to permeate through

the cover zone.

4.4.4.5 Allowance for abrasionThe cover shall be increased by the amount of any anticipated abrasion. This may be limitedby making provision to repair the abrasion. This additional cover shall not be considered tocontribute to the strength of the member.Concrete in contact with liquid flowing at velocities greater than 4 m/s shall be protectedfrom abrasion.

4.5 DURABILITY OF METAL FIXTURES IN CONTACT WITH CONCRETEMetallic items that protrude from the concrete shall be designed so that galvanic corrosionbetween the buried and exposed portions will not occur. Aluminium shall be isolated fromany wet concrete by a moisture-proof coating, lining or gasket.

4.6 DURABILITY OF WATERSTOPS, SEALANTS AND OTHER ASSOCIATEDITEMSWaterstops, sealant and other associated items shall be designed in accordance withSection 6.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


19

S E C T I O N 5 M A T E R I A L A N D C O N S T R U C T I O NR E Q U I R E M E N T S

5.1 GENERALThe material and construction requirements of AS 3600 shall apply.

5.2 CONCRETE5.2.1 GeneralConcrete shall comply with the requirements of AS 1379 and Clause 4.3.5.2.2 CuringConcrete members shall be initially cured continuously for at least 7 days under ambientconditions or cured by accelerated methods so that the average compressive strength at thecompletion of curing is not less than 75% of the specified f c.Correct curing is vital to providing concrete of the required durability. The method ofcuring shall ensure that the surface layer of all concrete surfaces remain moist at all timesduring the curing period.5.2.3 Pneumatically applied concreteFor pneumatically applied concrete, the designer should agree on full specificationrequirements with the contractor for materials, mix proportions, mixing, placing, equipmentand curing before commencement of works.

5.3 REINFORCEMENT5.3.1 Protective coating5.3.1.1 GeneralProtective coatings shall not permit reduction of the required cover specified in Clause 4.4.

NOTES: 1 The reinforcing tie wire or any corrodible item shall not transgress the concrete cover space

(see Clause 4.4.5.4).2 Stainless steel reinforcement may be used.

5.3.1.2 GalvanizedReinforcement may be hot-dip galvanized as specified in AS 2841, where applicable, orAS 4680 to a minimum coating thickness of 42 m.5.3.1.3 Epoxy coatedReinforcement may be epoxy powder coated with the coating bonded by an electrostaticfusion process. It is essential that the coating process is undertaken in factory conditionsand be as specified in ASTM A 775M.5.3.2 TendonsUnbonded tendons shall not be allowed except in special post-tensioned systems where thetendons are protected by a non-corrodible duct packed with insoluble, non-corrosive grease.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


20

S E C T I O N 6 J O I N T S , W A T E R S T O P S , J O I N TF I L L E R S , A N D S E A L A N T S

6.1 JOINTS6.1.1 PurposeJoints shall be provided where necessary(a) to break the structure in sections convenient for economical construction;(b) to control possible cracking resulting from excessive stresses and strains; and(c) to comply with design assumptions.Joints shall facilitate displacement or rotation, or both, without affecting the structuralintegrity or liquid-tightness of the structure.6.1.2 Non-movementConstruction joints, including a joint between precast segments, are located in a part of astructure for convenience of construction and made so that the load-carrying capacity andserviceability of the structure will be unimpaired by the inclusion of the joints. Criticallocations may require the placing of a waterstop across the joint.6.1.3 Movement6.1.3.1 GeneralMovement joints may require the installation of a waterstop, joint filler and sealant.6.1.3.2 IsolationIsolation joints shall completely separate two mating concrete faces sufficiently to allowcomplete freedom of relative movement.6.1.3.3 ExpansionExpansion joints are similar to isolation joints. They shall allow expansion towards andcontraction from the plane of the joint but prevent movement in other directions.6.1.3.4 Full contractionFull contraction joints are similar to expansion joints without compressible joint filler. Theyshall allow shrinkage away from the plane of the joint.6.1.3.5 Partial contractionPartial contraction joints are similar to full contraction joints except that a proportion of themain reinforcement is carried through the joint.6.1.3.6 HingedHinged joints shall allow some rotation between two sections while resisting both thrust andshear forces.

6.1.3.7 SlidingSliding joints shall allow a relative movement with a minimal restraint in the plane of thejoint.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


21

6.2 WATERSTOPSWaterstops are preformed strips that are wholly or partially embedded in the concreteduring construction. They are located across joints in the structure to provide a permanentliquid-tight seal during the whole range of joint movements.

6.3 JOINT FILLERSJoint fillers shall provide a compressible zone within a joint to allow minimum resistance toexpansion or articulation of the structure on either side of the joint.

6.4 SEALANTSSealants shall be made of impermeable ductile materials and shall provide a liquid-tightseal by adhesion to the concrete throughout the range of joint movements.

6.5 CONTAMINATION OF WATERWaterstops, joint fillers and sealants shall not contaminate potable water.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 37352001


22

S E C T I O N 7 T E S T I N G

7.1 GENERALInspection and testing for safety, serviceability and durability shall be carried out oncompletion of construction.

NOTE: Inspections should be carried out at regular intervals (maximum 5 years) during theservice life of the structure.

7.2 TESTING FOR LIQUID-TIGHTNESSAt an appropriate time after completion of construction, the structure or section thereof asconsidered necessary shall be tested for liquid-tightness in accordance with Clauses 7.3 and7.4.

7.3 TESTING OF LIQUID-RETAINING STRUCTURESFor a test of liquid retention, a structure shall be cleaned and initially filled with thespecified liquid (usually water) at a uniform rate generally not greater than 2 m in 24 h.Structures shall not be backfilled unless specified.When first filled, the liquid level shall be maintained by the addition of further liquid for astabilizing period of 7 days while absorption and autogenic healing takes place. After thestabilizing period, the level of the liquid surface shall be recorded at 24 h intervals, for atest period of 7 days. During this 7-day test period, the total permissible drop in level, afterallowing for evaporation and rainfall (if the test is made for an uncovered structure) shallnot exceed 1/500th of the average water depth of the full tank or 10 mm, whichever is less.Notwithstanding the satisfactory completion of the test, any evidence of seepage of theliquid to the outside faces of the liquid-retaining walls or intensified underdrain flow shallbe assessed against the requirements of the specification. Any necessary remedial treatmentof the concrete to the cracks or joints shall, where practicable, be carried out from the liquidface. When a remedial lining is applied to inhibit leakage at a crack it shall have adequateflexibility and have no reaction with the stored liquid. (See Clause 6.5.)Where the structure fails to satisfy the 7-day test then, after completion of the remedialwork, it shall be refilled and a further 7-day test undertaken in accordance with this Clause.

7.4 TESTING OF ROOFSWhere applicable, the roofs of liquid-retaining structures shall be watertight and shall,where practicable, be tested on completion by flooding the roof with water to a minimumdepth of 25 mm for a period of 24 h or longer if so specified. Where it is not possible, tocontain 25 mm depth of water, because of roof falls or otherwise, a hose or sprinkler systemshall provide a sheet flow of water over the entire area of the roof for a period of not lessthan 6 hours. In either case, the roof shall be considered satisfactory if no leaks or damppatches show on the soffit. Where the structure fails to satisfy either of these tests, thenafter the completion of the remedial work it shall be retested in accordance with thisClause. The roof covering, if any, should be completed as soon as possible after satisfactorytesting.

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

Standards AustraliaStandards Australia is an independent company, limited by guarantee, which prepares and publishesmost of the voluntary technical and commercial standards used in Australia. These standards aredeveloped through an open process of consultation and consensus, in which all interested parties areinvited to participate. Through a Memorandum of Understanding with the Commonwealth government,Standards Australia is recognized as Australias peak national standards body.

Australian StandardsAustralian Standards are prepared by committees of experts from industry, governments, consumersand other relevant sectors. The requirements or recommendations contained in published Standards area consensus of the views of representative interests and also take account of comments received fromother sources. They reflect the latest scientific and industry experience. Australian Standards are keptunder continuous review after publication and are updated regularly to take account of changingtechnology.

International InvolvementStandards Australia is responsible for ensuring that the Australian viewpoint is considered in theformulation of international Standards and that the latest international experience is incorporated innational Standards. This role is vital in assisting local industry to compete in international markets.Standards Australia represents Australia at both ISO (The International Organizationfor Standardization) and the International Electrotechnical Commission (IEC).

Electronic StandardsAll Australian Standards are available in electronic editions, either downloaded individually from our Website, or via on-line and CD ROM subscription services. For more information phone 1300 65 46 46 orvisit us at

www.standards.com.au

Lice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

GPO Box 5420 Sydney NSW 2001Administration Phone (02) 8206 6000 Fax (02) 8206 6001 Email [email protected] Service Phone 1300 65 46 46 Fax 1300 65 49 49 Email [email protected] www.standards.com.au

ISBN 0 7337 3714 5 Printed in AustraliaLice

nsed

to Is

hea

A Be

ddin

g on

11

Jan

2005

. 1 u

ser p

erso

nal u

ser l

icenc

e on

ly. S

tora

ge, d

istrib

utio

n or

use

on

netw

ork

proh

ibite

d.

AS 3735-2001 Concrete structures for retaining liquidsAS 3735-2001 CONCRETE STRUCTURES FOR RETAINING LIQUIDSPREFACECONTENTSSECTION 1 SCOPE AND GENERAL1.1 SCOPE AND APPLICATION1.1.1 Scope1.1.2 Application

1.2 REFERENCED DOCUMENTS1.3 DEFINITIONS1.4 NOTATION1.5 USE OF ALTERNATIVE MATERIALS OR METHODS1.5.1 General1.5.2 Existing structures1.5.3 Ferrocement

1.6 DRAWINGS AND SPECIFICATIONS1.6.1 Design data1.6.2 Design details

SECTION 2 LOADS AND LOAD COMBINATIONS2.1 GENERAL2.2 LOADS AND OTHER ACTIONS2.2.1 Temperature2.2.2 Moisture variation2.2.3 Earthquake2.2.4 Other actions

2.3 STABILITY DESIGN2.4 LOAD COMBINATIONS FOR SERVICEABILITY

SECTION 3 DESIGN FOR SERVICEABILITY AND STRENGTH3.1 GENERAL3.2 REINFORCED CONCRETE3.2.1 General3.2.2 Minimum reinforcement ratio3.2.3 Limiting steel stresses for serviceability3.2.4 Limiting concrete thickness

3.3 PRESTRESSED CONCRETE3.3.1 General3.3.2 Analysis3.3.3 Limiting concrete stresses for serviceability3.3.4 Non-tensioned reinforcement3.3.5 Partial prestressing

SECTION 4 DESIGN FOR DURABILITY4.1 GENERAL4.2 EXPOSURE CLASSIFICATION4.3 REQUIREMENTS FOR CONCRETE4.4 REQUIREMENTS FOR COVER TO REINFORCEMENT (BARS AND TENDONS)4.4.1 General4.4.2 Cover for concrete placement4.4.3 Cover for corrosion protection4.4.4 Cover modifications for special circumstances

4.5 DURABILITY OF METAL FIXTURES IN CONTACT WITH CONCRETE4.6 DURABILITY OF WATERSTOPS, SEALANTS AND OTHER ASSOCIATED ITEMS

SECTION 5 MATERIAL AND CONSTRUCTION REQUIREMENTS5.1 GENERAL5.2 CONCRETE5.2.1 General5.2.2 Curing5.2.3 Pneumatically applied concrete

5.3 REINFORCEMENT5.3.1 Protective coating5.3.2 Tendons

SECTION 6 JOINTS, WATERSTOPS, JOINT FILLERS, AND SEALANTS6.1 JOINTS6.1.1 Purpose6.1.2 Non-movement6.1.3 Movement

6.2 WATERSTOPS6.3 JOINT FILLERS6.4 SEALANTS6.5 CONTAMINATION OF WATER

SECTION 7 TESTING7.1 GENERAL7.2 TESTING FOR LIQUID-TIGHTNESS7.3 TESTING OF LIQUID-RETAINING STRUCTURES7.4 TESTING OF ROOFS

conditions: This is a licensed electronic copy of a publication where copyright is ownedor managed by Standards Australia International. Your licence is a 1 userpersonal user licence and the publication may not be stored, transferred orotherwise distributed on a network.You may also make one paper copy ofthis publication if required for each licensed user.purchdate: 11 Jan 2005purchby: Ishea A BeddingTitle: AS 3735-2001 Concrete structures retaining liquids

as 3735-2001 concrete structures retaining liquids

Documents

current standard

user personal user licence

information current

conditions of use

spa association of n

services n

concrete structuresfor

committee ce