Shear Interaction for Appendix D

[JAX91]

I am designing the anchor rods for a pre-engineered metal building. The PEMB engineer placed x-bracing in the end walls. For the load case with wind load parallel to the frame, they are giving me shear parallel to the frame from the x-brace and shear perpendicular to the frame from sidewall pressure. In total I have and tensile force of roughly 12 kip, a shear force parallel to the wall equal to roughly 9 kip, and a shear force perpendicular to the wall equal to roughly 11 kip. My columns are sitting on pedestals with limited edge distance, so supplementary reinforcement is required for all three cases.

The code requires an interaction ratio equal to or less than 1.2. In this case, would it be appropriate to use Nu/φNn + Vuparallel/φVnparallel + Vuperp/φVnperp < 1.2? This may be overly conservative for the steel strength itself. With checking the steel for shear, I may use Vu equal to the resultant shear. I’m not sure how I would combine this with tension, however. Any thoughts?

 

[Archie264]

Sorry, this won't be of any help, I wish it was. But, I think the fact that you haven't gotten any replies yet says a lot about the useability of Appendix D.

 

[WARose]

To tell you the truth, I’ve never used Appendix D for the steel design (just the strength of the bolt group in concrete). The main reason being that the interaction formulas they have don’t consider bending in the bolts. Therefore, I’ve typically checked by AISC’s provisions. The y have provisions for combined tension & shear, and also combined tension and bending. (They also give you a capacity for the bending strength of round bars.)

 

[tonycampos88]

I would just check the resultant shear force combined with tension for the interaction equation. Because you are in a pedestal, you will need stirrups around the anchors for sure, there are some nice papers that talk on how to design them.