Live Load Vs Dead Load For Roofs

L r l o r 1 r 2.

Live load vs dead load for roofs.

Af pa s appendix a lists a variety of live and dead load combinations for floors ceilings and rafters. Load types loads used in design load equations are given letters by type. Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states. Lr maximum roof live load anticipated.

Live loads on floors and roofs consists of all the loads which are temporarily placed on the structure for example loads of people furniture machines etc. For example appendix a indicates that one type of clay tile roof system has a live load value of 20 psf and a dead load value of 15 psf. This issue of live load vs. The total dead plus live loads equal the gravity load of the structure.

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. H design lateral pressure for soil condition type. Live loads are also called as imposed loads. L design floor live load.

Live loads keep on changing from time to time. D estimated mean dead weight of the construction. Roof live load may be reduced by the following equation. Victor staley a building official in the town of brewster mass responds.

Roof live load reduction. Where l r shall not be less than 12 psf and not more than 20 psf. Where d is floor dead load. The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated.

1the load combinations and factors are intended to apply to nominal design loads defined as follows. Structural steel offers much less of a dead load and provides superior support for live loads in multi story buildings. The dead loads are permanent loads which result from the weight of the structure itself or from other permanent attachments for example drywall roof sheathing and weight of the truss. 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.

Natural and engineered wood rest relatively lightly on the foundation but support less live loads than steel and concrete.