Concrete Through Bolt Design

[tmunford]

I am trying to design a through bolt for a thin, 2.5" thick, concrete slab. The bolt has both shear and tensile forces. I have read through ACI 318 Appendix D, but can't find any information on through bolts. I have checked for punching shear for the tensile force, but I'm not sure how to check the shear strength. Any advice?

 

[ishvaaag]

You may subject the hole to forces satisfying equilibrium with the applied loads in a FEM 3D model to see what tensile stresses develop. Adding the tensile solicitations in the face will give the worst. Then check against some limit of allowed tensile strength for the concrete.

 

[dcarr82775]

On DT flanges I've done yield line analysis to see if I think I will break the flange. I then limit bolt strength so that I am confident I can't break the flange.

I try to stay away from FEM whenever I can. It can be time consuming, and elastic analysis isn't the way to go when looking at potential failure modes.

 

[Spanky7]

Are you using plates on the both sides of the anchor? Typically I would size a plate on each side of the anchor that is large enough to satisfy the punching shear requirement of ACI 318 for the respective compression or tensile forces.

 

[slickdeals]

If you are in the middle of a slab, I don't think you can shear through it. I don't think you would need to check for shear.

We are Virginia Tech
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[ishvaaag]

Well a hard inset could develop moments in so thin plate and cause wedge failures upon the moment developed by the shearing force respect the center of the plate, so some check may be appropriate.

Cantilever insets in masonry used to be checked in simplistically way by balancing the moment outside with a moment (based in linear triangular diagrams of stresses Compression-Tension) then checking the maximum stresses against allowable.