Porch Knee Brace Calc

[WTFD4V1D]

So I have a porch addition to an existing house that I want to put knee braces on (outer edge of the porch). I have half the seismic load (dead load*seismic response coefficient/2) going to that side of the porch which is about 1200 pounds. Should I be distributing that load into each knee brace or should I model it as a frame with pinned connections at the base and zero rotation at the joints and divide the moment at each joint by the vertical height of the knee brace to find the couple force?

 

[JAE]

You should not be using knee braces in high seismic areas. Not sure if you are in one or not.

I'm not sure I understand your question but typically I would model in computer or hand analyze any knee braced frame to get the results.

 

[msquared48]

1200# seems like a lot of load for a porch.

I would take the load to the building through the roof diaphragm.

Mike McCann
MMC Engineering