ASCE7-10 Section 27.4.7 Minimum Wind Loads on Open Buildings
ASCE7-10 Section 27.4.7 Minimum Wind Loads on Open Buildings
(OP)
I have a question on how to apply the minimum wind load of 16psf per section 27.4.7 of ASCE7-10 on open buildings. (This is for the design of Solar carport type structure).
My design values are as follows:
Wind Speed V=100 MPH
Exposure = B
Risk Category = I
Enclosure Classification = Open Building
Average Roof Height = 12ft
Roof Angle = 5 Degrees
Kd = 0.85
Kz = 0.57 (ASCE7-10 Table27.3-1)
Kzt=1.0
G = 0.85
Monoslope Roof
Therefore, qh = 0.00256KzKztKdV^2 = 12.4 PSF
This value is less than that of section 27.4.7. Section 27.4.7 states that "The design wind force for open buildings shall be not less than 16 psf multiplied by the area Af". This section does not say to use a minimum "Velocity Pressure, qh" of 16 psf. Therefore, when designing an open building for the MWFRS wind loads per section 27.4.3 and Figure 27.4-4, I am assuming that I use the qh = 12.4 PSF and not 16PSF.
That is where I am confused, how do I apply the minimum 16 PSF wind load to the structure? Do I apply a uniform load of 16 PSF in addition to the pressures of section 24.7.3 or am I suppose to use qh=16 PSF in the loading of section 27.4.3?
My design values are as follows:
Wind Speed V=100 MPH
Exposure = B
Risk Category = I
Enclosure Classification = Open Building
Average Roof Height = 12ft
Roof Angle = 5 Degrees
Kd = 0.85
Kz = 0.57 (ASCE7-10 Table27.3-1)
Kzt=1.0
G = 0.85
Monoslope Roof
Therefore, qh = 0.00256KzKztKdV^2 = 12.4 PSF
This value is less than that of section 27.4.7. Section 27.4.7 states that "The design wind force for open buildings shall be not less than 16 psf multiplied by the area Af". This section does not say to use a minimum "Velocity Pressure, qh" of 16 psf. Therefore, when designing an open building for the MWFRS wind loads per section 27.4.3 and Figure 27.4-4, I am assuming that I use the qh = 12.4 PSF and not 16PSF.
That is where I am confused, how do I apply the minimum 16 PSF wind load to the structure? Do I apply a uniform load of 16 PSF in addition to the pressures of section 24.7.3 or am I suppose to use qh=16 PSF in the loading of section 27.4.3?






RE: ASCE7-10 Section 27.4.7 Minimum Wind Loads on Open Buildings
RE: ASCE7-10 Section 27.4.7 Minimum Wind Loads on Open Buildings
"It is imperative Cunth doesn't get his hands on those codes."
RE: ASCE7-10 Section 27.4.7 Minimum Wind Loads on Open Buildings
RE: ASCE7-10 Section 27.4.7 Minimum Wind Loads on Open Buildings
Load Case A: Wind Direction=0 Degree: Cnw = 1.2, Cnl=0.3; Therefore Pnw=12.7psf and Pnl=3.2psf
The carport structures are "T" shapes (See attachment). The unbalanced loading of figure 27.4-4 will induce a moment on the structure unlike a uniform 16PSF structure. I guess I would need to check both the unbalanced loading above and a uniform 16psf? I just want to be sure that I don't use the minimum 16PSF pressure when calculating p with the Cnw and Cnl coefficients.
RE: ASCE7-10 Section 27.4.7 Minimum Wind Loads on Open Buildings