Roof Live Load Tributary Area

Now let s find the tributary areas of a deck to determine the maximum load capacity of your deck start by calculating its total area and multiply by 50 psf.

Roof live load tributary area.

0 9d 1 0w a load factor of 1 6 when adding to load 7. The reduction formula has two reduction terms. If the load is 100 psf the load to the beam would be 12 ft x 100 psf 1200 plf. Minimum uniformly distributed live loads adapted from sei asce 7 10.

Tributary width is 7 ft 5 ft 12 ft. The left wall has 7 ft of tributary width and would receive a load of 700 plf. The amount of reduction allowed depends on the tributary area that a member supports and is automatically determined. Note to builder customer.

Tributary areas many floor systems consist of a reinforced concrete slab sup ported on a rectangular grid of beams. 0 9d 1 0e effect or 0 9 when resisting the load when permanent. Don t get confused with what weight you might think or want to load the deck with. The load w that that unit length supports equals the tributary area 1 tw times the uniform pressure load q.

1 2d 1 0e l 0 2s when h loads are present they shall have 6. R 1 is formulated in such a way that there is no reduction for tributary areas less than 200 sqft and is maximum when the tributary area reaches 600 sqft varying linearly in between. Such a grid of beams reduces the span of the slab and thus permits the designer to reduce the slab thickness. One for the tributary area supported by the structural element r 1 and the other for the slope of the roof surface r 2.

Our sample homes are in an area where the snow load is 50 pounds per square foot of roof area treat snow as live load. Minimum design loads for buildings and other structures location uniform load psf. The idealized beam loading diagram is shown in figure ta 2 3. Some building codes will permit the live load to be reduced only for some design members.

So a 100 sqft deck would be designed to support 5000 lbs. The area that it supports equals the tributary width times the unit length. It goes without saying that in a warmer climate the snow load probably would be less so you need to check your code book for live loads and dead loads in your region. Additional collateral gravity cg and collateral uplift cu loads can be added to the building or shape as required on the live load tab as well to account for additional loading on the roof surfaces.

Tributary loading or tributary widthis the accumulation of loads that are directed toward a particular structural member.