Roof Dead Load Calculation Example

Roof live load may be reduced by the following equation.

Roof dead load calculation example. A table of roof material weights including sheathing insulation and other decking materials. For wind the analysis of overturning should also consider roof uplift forces unless a separate load path is designed to transfer those forces. However in my practice i typically use the horizontal run of the roof for both types of load. To do this i use conservative too heavy dead loads and full snow loads regardless of pitch.

Load types loads used in design load equations are given letters by type. L r l o r 1 r 2. For dead loads you are correct. 6the 0 6 reduction factor on d is intended to apply to the calculation of net overturning stresses and forces.

Typical unit area dead load calculations. 910 pounds per lineal foot. Where l r shall not be less than 12 psf and not more than 20 psf. 50 psf x 14ft 700 pounds per lineal foot.

Used but they typically defined the load cases or combination stress or strength limits and deflection limits. 3 3 dead loads dead loads consist of the permanent construction material loads. Where d is floor dead load. Technically you should use the actual rafter length when adding up the weight of roofing materials.

Example roof truss analysis 3 6 stability determinacy assume that truss is externally statically determinate for gravity loads num forces 33 3 36 num eqns 18 x 2 36 therefore stable determinate dead load roof ceiling wt. Weight psf 20 ga metal deck 2 5 waterproof membrane with gravel 5 5. 15 psf x 14ft 210 pounds per lineal foot. 11 04 2014 computing the unit dead load for a region of surface area generally starts by identifying the region of a roof plan floor plan or elevation where the unit load is needed then looking at a typical section of that area to see how it is constructed.

R 1 1 for a t less than or equal to 200 psf r 1 1 2 0 001 a t for between 200 psf and 600 psf.