Stress Increase for Snow Load
Stress Increase for Snow Load
(OP)
In previous additions of ASD design (specifically AISC and AISI) was it permitted to increase the allowable stress by 33% for stresses caused by snow loading. It has been suggested to me that this is the case, but I was only aware of the allowable stress increase for wind and seismic loading. I am evaluating an existing building (PEMB of course) to see if it will be economical to retrofit for an additional roof load or if an additional support structure is needed. I would like to model the building fully to determine what the original capacity was and therefore can present the owners with a clear view if additional support is needed. Thanks much!






RE: Stress Increase for Snow Load
RE: Stress Increase for Snow Load
RE: Stress Increase for Snow Load
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Stress Increase for Snow Load
RE: Stress Increase for Snow Load
PEMB's typically dont work to modern codes when checked, so expect to have issues analyzing the existing situation.
RE: Stress Increase for Snow Load
"All allowable stresses and soil bearing values specified in this dode for working stress design may be ind=creased one-third when considering wind or eatrthquake forces either when acting alone or when combined with vertical loads. No increase will be allowed for vertical loads acting alone."
This implies no increases for USD concrete design, nor steel design. However a 1.15% increase was still allowed for wood for snow under section 2504(c)4,ii.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Stress Increase for Snow Load
BA
RE: Stress Increase for Snow Load
RE: Stress Increase for Snow Load
In CSA 086-2001, kD has only three categories, namely short term (1.15), standard term, which includes snow (1.00) and permanent duration (0.65).
For steel construction, load duration has never been considered.
BA
RE: Stress Increase for Snow Load
But, overall IMHO the snow load increase of 1.15 is a good factor for wood.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: Stress Increase for Snow Load
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Stress Increase for Snow Load
RE: Stress Increase for Snow Load
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com