Live Load Reduction 1

[Zulak]

On a 5-story, loadbearing wall building, does the loadbearing wall qualify as a "column" or a "beam" when determining live load reduction? (I believe the equation is similar in most codes)

 

[JAE]

I would look at it as a column-type element in terms of the axial load applied. The difficulty is in developing the proper tributary area for the live load reduction. Some engineers I know would take a one foot strip of wall, and only include the one foot strips of floors and roof tributary to it in their calculation of tributary area.

Others would resolve that any loading in a floor above would spread out in a rigid-type wall (such as masonry or concrete) and therefore, you should be able to take into account a larger area at each floor as influencing the wall.

 

[chichuck]

In ASCE 7-02,the reduction factor is based on influence area, not tributary area. see the commentary for an explanation of influence area. It is different from tributary area. The one foot wide tributary area mentioned above is definitely not correct, a much larger influence area should be used.

I'm not familiar with other codes.


regards,

chichuck

 

[mjohan]

The best code I have seen which clearly describes when and where to use a live load reduction is the IBC 2000.

Under section 1607.9.2 "Alternate floor live load reduction" it states "Such reductions shall apply to slab systems, beams, girders, columns, piers, WALLS, and foundations."

The code further states the exact formulas to use when taking live load reductions for the above structural elements. Their is a 60% maximum reduction for vertical members, which is more of a reduction than the standard 40%.

Hope this helps