Other considerations for sloped roofs can be found throughout chapter 7 of asce 7 10.
Roof snow load map.
Psf pounds per square foot above line 60 psf.
To calculate roof snow load per residential building code.
In areas of the state outside of certified local government jurisdictions the design snow load shall be based on the ground snow loads developed in snow loads for structural design in montana authored by f f.
The ground snow load map shown below was scanned from the asce 7 10 figure 7 1.
60 ground snow psf below line 50 psf 50 ground snow psf.
A great deal of confusion currently exists among engineers architects recreation specialists and maintenance personnel concerning the proper snow loading to use for the design and maintenance of trail bridges building roofs and other structures in mountainous high snow load areas.
The north zone middle zone and the south zone are identified on the roof load zone map above.
Schilke civil agricultural engineering montana state university august 1989.
A b c d e f g h 1 j k l m n o p q r s t u v w y.
0 7 x 60 psf 42 psf below line.
0 7 x 50 psf 35 psf.
The latitude and longitude elevation normalized ground snow load and ground snow load are displayed for the user for any selected location.
Ground snow loads of 684 communities listed aphabetically by town name.
Roof snow loads are based on the historical records for ground snow loads for a given location however the local building authority should always be consulted to determine the correct roof snow load to use for a given site and application.
This downward imposed load on the home is also known as the snow load.
In our case let s assume that our structure has a flat roof roof slope 5.
0 7 x pg ground snow load pf roof snow load roof snow load examples.
The ground snow loads to be used in determining the design snow loads for roofs shall be determined in accordance with asce 7 or figure 1608 2.
When using figure 1608 2 for sites at elevations above 1 000 feet 304 m the ground snow load shall be increased from the mapped value by 2 psf 0 095 kn m2 for every 100 feet 30 480 mm above 1 000.
Additionally users can navigate around the map by zooming in out and moving north south east west and then clicking a location on the map to determine a ground snow load value for the selected location.
The snow load that is applied to our structure is not the ground snow load but in most cases the flat roof snow load.
The minimum design roof snow load.
The north zone design live load equates to 40 pounds per square foot the middle zone equates to 30 pounds per square foot and the south zone equates to 20 pounds per square foot.
The flat roof snow load is calculated using formula 7 3 1.
