ASCE 7-05 APPENDIX C (Serviceability considerations)

[malikasal]

appendix c of ASCE 7-05 states that :

"For serviceability limit states involving visually objectionable deformations, repairable cracking
or other damage to interior finishes, and other short-term effects,
the suggested load combinations are:
D + L (CC-1a)
For serviceability limit states involving creep, settlement, or
similar long-term or permanent effects, the suggested load combination is:
D + 0.5L "

does that mean that the wind load should not be considered when checking the deflection of a purlin?



ôIf you don't build your dream someone will hire you to help build theirs.ö

Tony A. Gaskins Jr.

 

[wannabeSE]

The IBC has wind load deflection limits. See section 1604.3.

 

[Hokie93]

Wind does not need to be considered when checking long-term or permanent effects. For checking short-term effects, you should consider deflection due to wind load. ASCE 7-10 Appendix C Commentary provides Equation (CC-3) just for this purpose. Note the W_a term is recommended to be based on some reduced wind speed (lesser mean recurrence interval than that used for strength design) to be selected by the engineer based on engineering judgment. Putting it all together, for many common (i.e., low-slope) roof framing scenarios, the positive wind pressure is relatively low and not likely to control deflection over live, snow, or rain load.