Question on ASCE 31-03

[msquared48]

I am presently looking at doing a Tier 1 or 2 analysis on an existing Tilt-up warehouse built circa 1983.

Problem is that the building is being converted from a warehouse occupancy to a school. If the occupancy is over 250, then the category goes from II to III, and the importance factor to 1.25 from 1.00.

The question is that I have found no mention of any importance factor in ASCE 31-03, and to properly anlyze the structure for it's intended use, in my mind, this should be included. Am I missing something here?

The obvious answer is that I could just include it in the gross shear analysis, but that would be too easy...

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[ishvaaag]

According to this article, it seems it is a philosophical issue, they have elected to follow a different path to the checks.

http://cobweb.ecn.purdue.edu/~ce573/Documents/ASCE31 and ASCE41 What Good Are They Final.pdf

Since existent they seem to think that if the building has met their requirements the construction is valid.

 

[msquared48]

Interesting Article, but focuses more on the "R" and other disparities, with no real discussion on "I" change issue.

I may just tweek the system here after I talk with the reviewing agency to get their input. Heck, if the occupancy is less than 250, the problem goes away.

Thanks for the input though.

Just as a thought though, any one ever used the publication with any perceived success? Any thoughts on it?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Orthotropic]

ASCE 31 uses "Level of Performance" in lieu of "Occupancy Category". ASCE 31 only includes Life Safety and Immediate Occupancy and typically Occupancy Category III structures would fall somewhere in between. The IEBC has some discussion on how to Consider these structures.

Many people use ASCE 31 for evaluating if voluntary upgrades are warranted, and except where used in conjunction with the IEBC, it is generally not adopted code language. Therefor, many engineers do "tweek" the standard depending upon project specifics and the needs and expectations of the owner, and their own engineering judgment. Just be clear in your report what deviations you made from the standard.