critical section for shear (footing with masonry wall)

[hoshang]

https://www.eng-tips.com/viewthread.cfm?qid=344343

why the critical section for shear (footing with masonry wall) is calculated at a distance 0.25*t from the face of the wall.

Hi all
In your opinion where the critical section for shear (footing with masonry wall) should be located? Is it at d from the face of the masonry wall?

 

[Roukkia]

What code are you using? This is directly addressed in ACI

 

[hoshang]

This is directly addressed in ACI

Where? Which section? Which edition?

 

[BAretired]

The critical section for shear in a slab is at d/2 from the face of wall.

BA

 

[Roukkia]

hoshang - You would take it at a 45 degree angle from the location indicated in Table 13.2.7.1 of ACI318-14.

 

[hoshang]

Mind that the footing is for masonry wall in the original post. I reviewed Example 8-12 of Bowles' Foundation analysis and design. In there, wide-beam shear is checked at the face of the wall (not d out) for the most severe condition.

 

[JLNJ]

Looks like a typo. That's why you don't trust random online people - like us!

 

[BAretired]

Mind that the footing is for masonry wall in the original post. I reviewed Example 8-12 of Bowles' Foundation analysis and design. In there, wide-beam shear is checked at the face of the wall (not d out) for the most severe condition.

I don't have a copy of Bowles' Foundation Analysis and Design, but I would not argue with his choice of critical section, even though it is a little conservative.

I don't remember ever finding a strip footing to be critical in shear, so I am wondering what gave rise to this question.

Looks like a typo.

What looks like a typo?

I suspect Bowles was making allowance for the possibility that the material in a masonry wall may be a bit softer than a solid concrete wall. I still wonder whether it makes much of a difference.

BA

 

[slickdeals]

Read 13.2.7.2 in combination with Table 13.2.7.1.
Location is measured at "d" from a point halfway between the face and center of the CMU wall.

 

[hoshang]

why the critical section for shear (footing with masonry wall) is calculated at a distance 0.25*t from the face of the wall.

Location is measured at "d" from a point halfway between the face and center of the CMU wall.

slickdeals, thanks. I reviewed section 13.2.7.2 and Table 13.2.7.1 of the ACI Code. I don't know why Bowles wrote "for the most severe condition". The critical section as stated in ACI Code will provide more Vu than the one calculated at the face of masonry wall (where Bowles calculated his Vu).

 

[Roukkia]

In 13.2.7.2, it references 7.4.3 which says to take the critical section for shear as "d" away from the critical section for Mu. Wouldn't this be a less Vu than in the Bowles book?