Flexural Cracking's Effect on Shear Capacity

[B16A2]

If you have a normal reinforced concrete beam (non PT) that develops flexural cracks, how do you determine the reduced shear capacity at the cracked section? Cant seem to find any references that point to an answer.

 

[cooperDBM]

Don't know which design code you use but shear failure starting from a flexural crack is accounted for in the ultimate concrete shear strength. The ultimate concrete shear strength assumes that the section is cracked (ultimately on some diagonal) which may have been started from a flexural crack. In some codes, like ACI, the shear provisions for non-prestressed beams are so simplified (empirical) that it's not explicit. The ACI approach for prestressed girders explicitly calculates the concrete shear strength as limited by a shear crack starting from flexural cracking (Vci) or web cracking (Vcw).

In the Canadian codes the concrete shear strength is determined from the state of stress following the ultimate shear crack without much regard to how the crack started.

I'm sure I could have explained all that more clearly - but flexural cracking is already considered in code provisions.