Roof Live Load Reduction

Roof live load reduction.

Roof live load reduction.

One for the tributary area supported by the structural element r 1 and the other for the slope of the roof surface r 2. If the roof design load is 20psf and you are considering the compression in a web member that is located near the mid span than i would not use live load reduction for the compression in that member. For uses other than storage where approved additional live load reductions shall be permitted where shown by the registered design professional that a rational approach has been used and that such reductions are warranted. Uniform live loads at roofs are permitted to be reduced in accordance with section 1607 12 2.

The live loads for members supporting two or more floors are permitted to be reduced by a maximum of 20 percent but the live load shall not be less than l as calculated in section 1607 10 1. 1607 10 reduction in uniform live loads. Hence the magnitude of the roof live loads should be specified as for a flat roof and the program allowed to make the reduction based on the slope of the framing. Likewise roof live loads in the hong kong building regulation can be reduced as a function of the slope.

Where uniform roof live loads are reduced to less than 20 psf 0 96 kn m 2 in accordance with section 1607 13 2 1 and are applied to the design of structural members arranged so as to create continuity the reduced roof live load shall be applied to adjacent spans or to alternate spans whichever produces the most unfavorable load effect. The reduction formula has two reduction terms. The commentary in asce 7 05 c4 about roof live load reductions explains the anticipated difference in use of roof areas vs. Commentary in asce 7 10 c4 8 about roof live load reductions explains the anticipated difference in use of roof areas vs.

On a roof with a slope greater than 4 to 12 the live load limit is typically adjusted downward from 20 psf to 15 psf to allow for the relatively greater dead load on the steeper roof. Except for uni form live loads at roofs all other minimum uniformly distrib uted live loads lo in table 1607 1 are permitted to be reduced in accordance with section 1607 10 1 or 1607 10 2. Live load reduction is a reduction in live load that contributes to the actions on a member.