From the general concept of load comes two major categories.
Live and dead loads for roofs.
In short the dead load of a structure comprises its completed weight usually measured in pounds per square foot before it goes into service.
Live loads keep on changing from time to time.
Analysis of point loading is best left to engineers.
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.
The roof shall be designed for the live load indicated in table r301 6 or the snow load indicated.
To correctly apply the values of the tables and.
Live loads are also called as imposed loads.
This issue of live load vs.
Point loads occur when a weight is imposed on one spot in a structure like a column.
How do they differ.
L r l o r 1 r 2.
Ground snow load might seem somewhat confusing until you read the basic premise that is identified in irc section r301 6 which states.
The values for dead loads in table 3 2 are for commonly used materials and constructions in light frame residential buildings.
6 2015 home builders jobsite codes note.
Loads used in design load equations are given letters by type.
3 3 dead loads dead loads consist of the permanent construction material loads comprising the roof floor wall and foundation systems including claddings finishes and fixed equipment.
The floors walls roof columns stairs permanent equipment and any fixed decor constitute a static load that normally doesn t change over the life of the building.
Live loads dead loads roof loads 2015 jobsite codes indd 5 12 15 15 3 22 pm.
On a roof with a slope greater than 4 to 12 the live load limit is typically adjusted downward from 20 psf to 15 psf to allow for the relatively greater dead load on the steeper roof.
Where d is floor dead load.
The roof is designed for the roof live load not more than 20 psf or the snow load whichever is greater.
The load is not shared equally by the supporting structure.
Victor staley a building official in the town of brewster mass responds.
Roof live load reduction.
D dead load l live load l.
Dead loads and live loads.
Where l r shall not be less than 12 psf and not more than 20 psf.
The structural supports of roofs and marquees shall be designed to resist wind and where applicable snow and earthquake loads in addition to the dead load of construction and the appropriate live loads as prescribed in this section or as set forth in table 1607 1.
Roof live load may be reduced by the following equation.
