Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
(OP)
I wonder if there are equations for the GCP external pressure coefficient. I am not really fond of the idea of using a graph like this one:






RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
It's difficult to program into a spreadsheet.
Iasonasx,
For G see equations 26.9-6, 26.9-7, 26.9-8, 26.9-9, 26.9-10, 26.9-11, 26.9-12, 26.9-13, 26.9-14, 26.9-15a, 26.9-15b and 26.9-16.
Values for Cp are taken from various tables, for example the one in Figure 27.4-1 for the Main Wind Force Resisting System for walls and roofs. Not sure where the components and cladding one is of the top of my head but it's probably in there somewhere.
If I were to try to present any one of those equations referenced above you'd think I had lost my mind. I hope the wind knows it needs to be raised to the .63 power, multiplied by .63, square-rooted, multiplied by 1.7 and other factors including one of them raised to the 1/6 power and multiplied by .925 along with other factors I left out.
At some point it might become simpler and cheaper to just build a model and pay for the wind tunnel testing.
RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
GCp = GCp·min + [GCp·max - GCp·min] * [LN(A) - LN(A·min)] / [LN(A·max) - LN(A·min)]
A = the area
A·min = Area corresponding to the minimum GCp on the sloping section
A·max = Area corresponding to the maximum GCp on the sloping section
RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
RE: Equation for wind calculation External Pressure Coefficient ASCE-7 pg. 335
=IF(Y9=4;IF(L9<10;1.1;IF(L9>500;0.8;1.1-((1.1-0.8)*(LN(L9)-LN(10))/(LN(500)-LN(10)))));IF(L9<10;1.4;IF(L9>500;0.8;1.4-((1.4-0.8)*(LN(L9)-LN(10))/(LN(500)-LN(10))))))
It works fine. thanks!