Girder Roof Truss Design

Buildings constructed in l or t shapes use girder truss systems where the roof changes direction.

Girder roof truss design.

Girder trusses are designed to carry additional loads other than standard roof loads. They have a top chord and a bottom chord separated by diagonal webs and vertical webs. Typically the building designer or builder will contract with the truss fabricator who will supply a truss layout and a structural design of each significant element of the roof system. Using these structures in roof design eliminates the need for a load bearing wall below resulting in open floor plans.

An advantage of the truss design for roofs is that ducts and pipes that are required for operation of the buildings services can be installed through the truss web i e. The truss plate manufacturer s engineer usually reviews and seals the individual truss designs on behalf of the truss fabricator. Trusses are triangular formations of steel sections in which the members are subjected to essentially axial forces due to externally applied load. Figure 6 1plane truss trusses are frequently used to span long lengths in the place of solid web girders.

Girder trusses have a long straight design. Girders may also be designed to accommodate special applications or designs. A girder truss is designed to support other secondary roof supports. Top general geometry for efficient structural performance the ratio of span to truss depth should be chosen in the range 10 to 15.