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1/3 stress increase for 5 psf interior w

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IIRC (I don't have my codes handy) the 5psf on interior walls is not wind 
loading, but just a specified lateral load.  This lateral load can result 
from people or material leaning against the wall but would most likely 
occur in an emergency situation where people are crowding together to get 
out of the building.  In a situation like this, you (at least I) don't want 
interior walls collapsing and obstructing egress.  Also, (again IIRC) the 
load for elevator shafts used to be 10psf to account for pressures built up 
during elevator operation but was reduced to 5psf about 20 years ago, which, 
again, is not a wind loading.

Although it is ambiguous in the UBC (thru 1997), other codes, ASCE 7 and the 
forthcoming IBC 2000 amongst them, have a minimum wind pressure of 10psf.

This loading of interior walls reminds me of when I was going to school, one 
of my classes was in one of the older buildings on campus.  The first time 
that I leaned on the hallway wall, I thought it was going to collapse.  A 
sharp push would have a wave traveling down the wall.

Hope this helps.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Dan Vines wrote:

>>I have designed (picked out of a catalog, really) interior load bearing
metal studs for a small office type structure.

Dale/Incor, in their catalog, provides allowable axial loads for various
stud sizes at various heights under various wind loading condtions (other
manufacturers provide the same info).  Anyway, they have a footnote that

For components subjected to 5 psf and greater lateral wind loads, the actual
bending and axial stresses were multiplied by 0.75 in accordance with AISI
Section A4.4

AISI sect. A4.4 states:  Where load combinations specified by the applicable
building code include wind or eq loads, the resulting forces may be
multiplied by 0.75.

The question is:  does the 5 psf interior wall loading prescribed by code
constitute a WIND load.  My boss and I both think so, but I would love a
second, third, or twelfth opinion.