Diaphragm and Collector Design

[tonycampos88]

Hello,

I have a concrete-over-metal deck 2nd floor diaphragm and I am trying to design the collector elements and their connection to the deck. My question if the forces according to the equation 12.10.1.1 (higher than the diaphragm forces for the SLRS at this level) still need to be multiplied by the overstrength factor (I am in SDC D) for the design of the collectors, or are these forces JUST for diaphragm design?

I am confused between doing either that, or multiplying the forces obtained from the Equivalent lateral force procedure by the overstrength factor for the collectors.

Thanks!

 

[steellion]

For Seismic Design Categories C through F, you need to multiply the seismic force by the overstrength factor (omega-sub-0) for the design of collector elements, their splices, and connections to the lateral force resisting elements.

 

[TDIengineer]

This part of the code is confusing.. When it comes to checking the diaphragm itself, you should using the Fp diaphragm design forces including a rho factor where usually Fpmin governs for your lower stories.

When designing the collector itself and drag beams, you use your seismic story shear Vx forces along with Omeganot (rho may be equal to 1.0 since you have overstrength being used).