Wall Anchorage Force 1

[CURVEB]

I'm designing the anchorage for a masonry bearing wall per ASCE 7-05, section 12.11.2. It is low seismic so the 280 plf requirement controls. The anchorage components are wood (2x braces from the top of the wall up to the first truss). I interpret the code as saying that 280 plf is a force (Fp). E = rho*Qe where Qe is the effect of seismic forces from V or Fp. Thus, my 280 plf force is E.

So for wood design using ASD, I can multiply this force by 0.7 to get it to service level, then use the Simpson table values for 160 load duration (wind/seismic).

Anyone see any flaws with this reasoning?

 

[DaveAtkins]

Yes, E is an LRFD force, so you can multiply by 0.7 (which results in 196 plf, approximately equal to the old UBC required force, 200 plf).

And yes, with wood you are allowed a 60% increase for load duration. No other material (concrete, masonry, or steel) allows any kind of increase; this is unique to wood.

DaveAtkins