Basis Of Concrete Water Tank Design

  • Prior to bending, plain section should be plain after bending
  • Both concrete and steel should be properly elastic and modular ratio value should contain a value provided in IS 456- Table 21.
  • While computing the stresses, both for flexural and direct tension or combination thereof concerning resistance to cracking, the whole section of concrete along with the cover as well as reinforcement.
  • The concrete tensile strength should not be considered throughout the strength calculation.

Allowable Stress On Concrete For Resisting Cracking

There should not be any leakage in water tank. For this purpose, M 20 grade and greater concrete should be used, and concrete near water face should be such that no crack takes place. The wall thickness of the water should be designed in such a manner that the stress on the concrete is smaller.

In members with thickness lower than 225mm and in contact with liquid on one side, these allowable stresses in bending apply also to the face remote from the liquid.


Allowable Stress In Steel

The stress in steel should not be permitted to surpass the following values under several positions to stop cracking of concrete.

  • When steel is provided adjacent to the face of the members in contact with liquid 115 N/mm2 for mild steel Bars and 150 N/mm2 for high strength deformed bars./li>
  • When steel is provided on the face far from the liquid for members 225 mm or more in thickness then allowable stress in steel should be 125 N/ mm2 for mild steel bars and 190 N/ mm2 for high strength deformed bars.
  • If steel is provided on face far from liquid for members lower than 225 mm in thickness similar to former.