Wind on single-span gabled and hipped roofs with a slope between 7 and 45 degrees for C&C
Figure 4.1.7.6.-E (NBC2020)
v1.0.0
Factors
User input values:
q: 1kPa
Importance Factor, ULS: Iw = 1.0
Ce = (h/10)0.2 (but not less than 0.9) = 0.9
Roof slope: 26.57 degrees
q: 1kPa
Importance Factor, ULS: Iw = 1.0
Ce = (h/10)0.2 (but not less than 0.9) = 0.9
Roof slope: 26.57 degrees
External Wind Pressure
Using figure for Gable and Hip roofs with slopes between 7 and 27 degrees.
| Zone | CpCg | pe (kPa) |
|---|---|---|
| c- | -5 | -4.5 |
| r- | -2.49 | -2.24 |
| s- | -3.7 | -3.33 |
| oc- | -7 | -6.3 |
| or- | -1.7 | -1.53 |
| os- | -4.2 | -3.78 |
| c+ | 0.78 | 0.7 |
| r+ | 0.78 | 0.7 |
| s+ | 0.78 | 0.7 |
Internal Wind Pressure
Cgi = 2
Cpi = -0.45 to 0.3
Cei = (hi/10)0.2 (but not less than 0.9) = 0.9
pi = Iw*q*Ce*Ct*Cgi*Cpi
pi = -0.81kPa to 0.54kPa
Combined Wind Pressure
Note: Overhung roofs include contributions from upper and lower surfaces. Therefore, the interior pressures is not combined with the exterior pressure at overhangs.
| Zone | Cpi=-0.45 p (kPa) | Cpi=0.3 p (kPa) |
|---|---|---|
| c- | -3.69 | -5.04 |
| c+ | 0.16 | 1.51 |
| r- | -1.43 | -2.78 |
| r+ | 0.16 | 1.51 |
| s- | -2.52 | -3.87 |
| s+ | 0.16 | 1.51 |
| oc- | -6.3 | -6.3 |
| os- | -1.53 | -1.53 |
| or- | -3.78 | -3.78 |
End Zone Width
The end-zone width is the lesser of:• 10% of the least horizontal dimension = 0.1m
• 40% of the height of the building (H) = 0.4m
but not less than:
• 4% of the least horizontal dimension = 0.04m
• 1m
z = 1m