Rafter Supported Cone Roof

The spans in this table are based on a maximum supported rafter span of 16 feet where the supported span is the total horizontal distance spanned by the roof rafters divided in half not the diagonal distance or the length of the rafter.

Rafter supported cone roof.

Purlins as shown in sample photos below are installed for rafter support. Doorsheet is a minimum of 8 high x 8 6 wide. By upper third here we mean one third of the length of the rafter from ridge to top plate. Roof is designed as a supported cone roof.

This roof ends in an octagonal hip. The columns are not welded to the floor to allow for thermal expansion of the tank. Frame or truss supported. This roof ends in an octagonal hip.

Fabricate install new supported cone roof the screening estimates are based upon the following assumptions. No hours are included for a dedicated fire safety watch. Supported cone roof with internal rafters columns is a common design in north america. Supported cone roof with external rafters columns is a common design in north america.

The braces struts or kickers should be within every 4 and should not be at a greater than a 45 degree angle towards the roof slope lower side. Roof plate shall be designed as continuous beam with uniform load comprising of roof live load and self weight of roof plate. Maximum rafter span of 16 feet. A collar tie is a horizontal roof rafter compression connector that is located in the uppermost third of the span of a pair of opposed sloped or gable roof rafters.

This table is simply a sample and may not be valid for your region. The system of rafters is provided to support the roof plate. Good access exists to tank for equipment and materials. The purlins are supported by vertical or slightly angled bracing.

A double roof using a norman truss common rafters supported by principal rafters top chords in this case and an unusual extra layer of common rafters on the lower half to form a gallerie. Ste makes the cone roof tanks in three type. Under the midsections of the rafters are purlins which support the common rafters and are supported by principal rafters. In finding this location we do not count the additional length of the rafter that supports the roof eaves overhang or soffit.

It is found on larger tanks where self supported cones are not possible.