For members 225mm or more in thickness 1250 kg/cm2
(v)Compressive stress in columns subjected to direct load 1250 kg/cm2
2.3.4. Stresses due to drying Shrinkage or Temperature Change.
(i)Stresses due to drying shrinkage or temperature change may be ignored
provided that
(a) The permissible stresses specified above in (ii) and (iii) are not
otherwise exceeded.
(b) Adequate precautions are taken to avoid cracking of concrete during
the construction period and until the reservoir is put into use.
(c) Recommendation regarding joints given in article 8.3 and for suitable
sliding layer beneath the reservoir are complied with, or the reservoir is
to be used only for the storage of water or aqueous liquids at or near
ambient temperature and the circumstances are such that the concrete will
never dry out.
(ii)Shrinkage stresses may however be required to be calculated in special
cases, when a shrinkage co-efficient of 300 x 10-6may be assumed.
(iii) When the shrinkage stresses are allowed, the permissible stresses,
tensile stresses to concrete (direct and bending) as given in Table 1 may
be increased by 33.33 per cent.
2.3.5. Floors
(i)Provision of movement joints.
Movement joints should be provided as discussed in article 3.
(ii) Floors of tanks resting on ground.
If the tank is resting directly over ground, floor may be constructed of
concrete with nominal percentage of reinforcement provided that it is
certain that the ground will carry the load without appreciable subsidence
in any part and that the concrete floor is cast in panels with sides not
more than 4.5m. with contraction or expansion joints between. In such
cases a screed or concrete layer less than 75mm thick shall first be placed