When Shear Failure is Not Diagonal Tension, What Do We do? 3

[IJR]

Pals

Shear formulas in code consider truss analogy and compute diagonal strengths

In conditions where construction joints interfere, especially where diagonal tension is not likely, eg at base of shear walls, code says check frictional shear transfer and use longitudinal reinf to resist shear.

I have a situation in between. A beam column connection say 2ft deep(60cm).The load is only 1/2 ft(15 cm) away from column face.It is a large point load

Diagonal crack is not likely and construction involves no construction joint

Can I rely on tension reinforcement and concrete to resist shear or should I add more stirrups as if diagonal tension?

respects
IJR

 

[civilperson]

For the portion of the beam within d from the support,design per ACI 11.8. Consider horizontal ties or stirrups similar to corbel or place both longitudinal and vertical shear reinforcement per 11.8.4 and 11.8.5.

 

[IJR]

civilperson

I know all that. But I want to know why? And why should I ignore the fact that the distance from point load to support is almost none?

Do you want to elaborate?

respects
ijr

 

[UcfSE]

What exactly are you wanting to know? Why would you ignore the location of your point load relative to its support?

 

[JAE]

IJR - I usually check both the diagonal shear concepts found in the early parts of chapter 11 and in cases where there are large concentrated loads I might also do calcs from both the bracket/corbel and the shear friction concepts found in later portions of chapter 11.

 

[UcfSE]

You may also use a strut-and-tie model for the point load close to your support.

 

[civilperson]

Short snd deep members, such as brackets, corbels, and deep beams transfer shear to the support by in-plane compressive stresses rather than shear stresses. Shear failure is sudden and brittle, due to concrete's limited capacity to sustain plastic deformation. Strut -and-Tie Model represents a useful design approach for shear critical structures.

 

[IJR]

Thanks UcfSe, Thanks Civilperson for just mentioning Strut-and-Tie Model. I guess that is what I was looking for

respects
IJR