When screw is subject to shear load with the shim between the joint

[jsu0512]

Hi Everyone,

I am designing the screw to transfer the shear load from the 1/4" thickness of steel plate to the underside of the HSS beam.

If there is 3/4" thickness of the plywood between the steel plate and the u/s of HSS beam, will this introduce a bending stress on the designed screw?

I've attached the diagram and calculation for your review and feedback. Please let me know if i'm on the right approach.

Thank you

 

[dhengr]

Jsu0512:
You have .25kN (56lbs.) of lateral loading out near the head of the screw, applied through the .25” bracket pl. The screw hole in that bracket pl. should be pre-drilled slightly oversized, so that the screw can not bottom out btwn. the screw head and any thread that it has made in that pl. Also, use this pl. as a drilling template for the plywd. and the HSS. Then the screw is essentially fixed at its thread into the side of the HSS, as it is tightened. The screw will act as a cantilever, pretty much fixed at the HSS, and maybe slightly restrained by the screw head on the pl. applying a bit of moment as it reacts against the bracket pl. when tightened. I would ignore this later restraint and treat the screw as a simple canti.