Civil Engineering - RCC Structures Design - Discussion

And if it exceeds two times then what is the answer?

Footing essentially acts as a wide beam.

Normally, in combined footing, we do not provide shear reinforcement. If nominal shear strength exceeds permissible shear strength, then its depth is increased so that nominal shear strength is less than permissible shear strength.

However, Shear reinforcement is provided when nominal exceeds permissible shear strength. It depends on dia, stress & spacing of stirrups. It is not fair to say 8 or 12-legged.

Please explain.

If shear stress is greater than 5kg/cm^2 then we use 12 legged stirrups and if it less than 5kg/cm^2 then we use 8 legged striups.

Not getting the Answer. Please explain to me in detail.

If the shear stresses not more than 5 kg/cm^2 = 8 legged stirrups.

And If Shear stress more than 5kg/cm^2 = 12 legged stirrups.

The Maximum shear stress depends type of the mix used. In no way any of the max allowed shear stress are more than 4N/Sqmm. Hence The following conclusions are offered.

1. Evaluate the Shear safety criteria based on type of the mix used.

2. If the shear stress at the critical cross section of the footing is more than maximum limit specified it is advised to.

A) Increase the depth of the footing.

B) Provide a string beam to take care of the shear forces without increase of the depth of the footing.

C) If the six or 8 legged stirrups are provided to counter the shear force then the sole criteria of design should be shear stress due to residual shear =total shear force- shear capacity of the section.

If it >5 then 12.

If <5 then 8 stirrups.

Right, thanks @VK Singh.

If it >5 than 12.

If <5 than 8 stirrup.