Shear Lug concrete breakout

[BAGW]

Hi
I am sizing the shear lug for seismic forces. I have a situation where pier is shallow. The 45 degree failure plane for concrete breakout of shear lug is controlled by height of pier. The amount of concrete area available for breakout is not sufficient to resist shear. I am adding a shear wall on both sides of the pier with width greater than the width of the shear lug. If I do this, I don’t need to check the concrete break out of shear correct as there is no free edge. Correct? Shear is transferred by bearing only correct?

 

[KootK]

Sounds right to me.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[BAGW]

ok Thanks

 

[BAGW]

With continuation of the above query, do I need to pay any special attention to pier wall interface design? The force is around 500kips. I am designing the wall as a shear wall with min horizontal and vertical reinforcement as per code and for the 500kips force.

 

[KootK]

There may be a fair bit to consider:

- bearing / bursting / load spread.
- potential for wall buckling.
- shear transfer from wall into soil, SOG, or neighboring foundations.

To get into specifics, we'd need to take a look at the specifics of your situation in plan and elevation.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[BAGW]

The pier is 3'x3' and the wall attaching to it is 2' wide. The shear lug is 1' wide.

- Bearing/Load spread: This should not be a problem as wall is 6'' bigger on either side of the lug.
- The wall is 1' wide and 5' tall. I dont think wall bucking will be an issue. Will look into it.
- Shear transfer from wall to the spread footing is transferred through the longitudinal bar friction extending into the footing.

The pier and the wall is modelled in FEM. Horizontal bars between pier and wall are provided per FEM model.

I have been trying to upload a pic but never works.

 

[KootK]

Still hard to visualize but, based on your description, nothing's jumping out at me as a deal breaker.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.