Roof Truss Load Path

All other forces will vary in magnitude duration and location.

Roof truss load path.

Load path loads on the roof are initially supported by the sheathing. Truss spanning between bearing walls. I for sloping or flat roof with slopes up to and including 10 degrees. 910 pounds per lineal foot.

The irc does not provide specific guidance as to when blocking may be required to transfer the loads directly. The building is designed for design load possibilities that may never occur. 15 psf x 14ft 210 pounds per lineal foot. Live loads on roof trusses.

The roof rafters transfer the loads to the ceiling joists and to the bearing walls that support the trusses. A primary goal for buildings subjected to high winds is to maintain a continuous load path from the roof to the foundation. To transfer loads from the wall above to the truss ends where they can be transferred to the wall below. Per ansi tpi 1 2014 section 7 5 2 1 figure 4 all loads being applied from roof trusses to wall and wall to ribbon board are considered to be applied as uniform plf loads.

All roof and wall loads are assumed to be uniform with no concentrated loads on the trusses or walls present. The live load shall be taken as follows. The sheathing transfers the loads to the roof rafters. Roof truss span tables alpine engineered products 15.

50 psf x 14ft 700 pounds per lineal foot. A when access is provided 1500 n m 2 b when access is not provided 750 n m 2 except for maintenance ii sloping roof with slope greater than 10 degrees. R roof live load w wind load s snow load e earthquake load r rain load. The truss could be designed based on the assumption that the 25 psf roof snow load is a factored ground snow load in which case a ground snow load is back calculated using asce 7 based on the specified roof snow load pg 25 psf therein lies the problem with specifying only a roof snow load.

If one part of the load path fails or is discontinuous building failure may occur. Design loads the building dead load is the only known load. It is important to list live load dead load and total load separately because live load is used to compute stiffness and total load is used to calculate strength.