Roof Dead Load Calculation Example

Used but they typically defined the load cases or combination stress or strength limits and deflection limits.

Roof dead load calculation example.

Roof live load reduction. 6the 0 6 reduction factor on d is intended to apply to the calculation of net overturning stresses and forces. 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. Typical unit area dead load calculations.

3 3 dead loads dead loads consist of the permanent construction material loads. 15 psf x 14ft 210 pounds per lineal foot. For wind the analysis of overturning should also consider roof uplift forces unless a separate load path is designed to transfer those forces. D dead load l live load l r live roof load w wind load s snow load e earthquake load r rainwater load or ice water load.

Technically you should use the actual rafter length when adding up the weight of roofing materials. For dead loads you are correct. Where l r shall not be less than 12 psf and not more than 20 psf. Load types loads used in design load equations are given letters by type.

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. 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. 50 psf x 14ft 700 pounds per lineal foot. 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. A table of roof material weights including sheathing insulation and other decking 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. 910 pounds per lineal foot.

L r l o r 1 r 2.