ISO 18407:2018

INTERNATIONAL ISO
STANDARD 18407
First edition
2018-05
Simplified design of prestressed
concrete tanks for potable water
Conception simplifiée du réservoir pour l'eau potable en béton pré-
armé
Reference number
©
ISO 2018
© ISO 2018
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Published in Switzerland
ii © ISO 2018 – All rights reserved

Contents Page
Foreword .vi
Introduction .vii
1 Scope .1
2 Normative references .1
3 Terms and definitions .1
4 Symbols .4
5 Design principles .12
6 Load .13
6.1 General .13
6.2 Deadweight .13
6.3 Imposed load .13
6.4 Hydrostatic water pressure .14
6.5 Prestress .14
6.5.1 General.14
6.5.2 Prestressing force immediately after prestressing .14
6.5.3 Effective prestressing force .18
6.5.4 Indeterminate forces due to prestress .19
6.6 Creep and drying shrinkage of concrete .19
6.7 Effect of temperature .19
6.8 Seismic action .20
6.9 Wind load .20
6.10 Snow load .20
6.11 Earth pressure .21
6.12 Uplift pressure force .22
6.13 Other loads .22
7 Structural analysis .22
7.1 Calculation of member force .22
7.2 Concrete .22
7.2.1 Strength .22
7.2.2 Modulus of elasticity.23
7.2.3 Poisson’s ratio .23
7.2.4 Drying shrinkage .23
7.2.5 Creep .23
7.3 Steel .25
7.3.1 Strength .25
7.3.2 Modulus of elasticity.26
7.3.3 Relaxation .26
7.4 Calculation of tensile reinforcement .26
8 Stress limit .27
8.1 General .27
8.2 Stress limit of reinforced concrete members .28
8.2.1 Stress limit of concrete .28
8.2.2 Stress limit of reinforcement .28
8.3 Stress limit of prestressed concrete members .28
8.3.1 Stress limit of concrete .28
8.3.2 Tensile stress limit of prestressing steel .29
8.3.3 Stress limit of reinforcement .29
8.3.4 Augmentation of tensile stress limit of concrete.29
9 Verification of safety against earthquake .29
9.1 Principles of seismic design .29
9.1.1 General.29
9.1.2 Ground motion levels .29
9.1.3 Levels of earthquake resistance .29
9.1.4 Effects of earthquake.30
9.1.5 Seismic design procedure .30
9.2 Input earthquake motion .30
9.2.1 Seismic design method .30
9.2.2 Design seismic coefficients for the seismic coefficient method for Level 1
ground motion .31
9.2.3 Design seismic coefficients for the seismic coefficient method for Level 2
ground motion .32
9.2.4 Seismic input for design by dynamic analysis .33
9.3 Verification of structural safety .33
9.3.1 Effects of earthquake.33
9.3.2 Combination of loads .37
9.3.3 Calculation of member forces .38
9.3.4 Safety verification .47
9.4 Investigation for foundation .54
10 General structural details .54
10.1 Prestressing steel .54
10.1.1 Clear distance .54
10.1.2 Concrete cover .55
10.1.3 Arrangement of curved prestressing steel .56
10.1.4 Arrangement of anchorages and couplers .56
10.1.5 Protection of anchorage zone .
...