Diaphragm Design Forces ASCE7-05 12.10.1.1
Diaphragm Design Forces ASCE7-05 12.10.1.1
(OP)
Equation 12.10-1 in Section 12.10.1.1 Diaphragm Design Forces of ASCE7-05 has the following equation:
Fpx=(nSUMi=x Fi)/(nSUMi=x wi)*wpx
It has been a while since college. I looked at Daniel T. Li's Seismic Analysis Based on CBC 2007 Chapter A found at http://www.engineering-international.com/
(See attached screenshot of this spreadsheet)
But I am having trouble computing the diaphragm design forces (roof and floor) myself.
Fpx=(nSUMi=x Fi)/(nSUMi=x wi)*wpx
It has been a while since college. I looked at Daniel T. Li's Seismic Analysis Based on CBC 2007 Chapter A found at http://www.engineering-international.com/
(See attached screenshot of this spreadsheet)
But I am having trouble computing the diaphragm design forces (roof and floor) myself.





RE: Diaphragm Design Forces ASCE7-05 12.10.1.1
Mike McCann
McCann Engineering
RE: Diaphragm Design Forces ASCE7-05 12.10.1.1
These Fx values in 12.8.3 are what 12.10.1.1 refers to when it says in the first sentence: "designed to resist design seismic forces from the structural analysis".
So your diaphragm must resist the forces from 12.8.3...but wait...you also have to AT LEAST design the diaphragm for the forces in equation 12.10-1 (which your spreadsheet apparently calculates).
...but wait again! Your values from Equation 12.10-1 don't need to be more than the given minimum of .2SDSIwpx and don't have to be more than twice that.
Your spreadsheet appears to include these max and min limits.
RE: Diaphragm Design Forces ASCE7-05 12.10.1.1
JAE, that is a clear explination of the code. That helps a lot.
My next question:
I did not create this spreadsheet and it is locked. I am having trouble finding out how the Fpx column is calculated. If I could only remember how to use sums (Fpx=(nSUMi=x Fi)/(nSUMi=x wi)*wpx) I'd be in good shape.
I have tried to get the Fpx column but I just can't seem to duplicate his answer.