Girder Roof Truss Design

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

Girder roof truss design.

They have a top chord and a bottom chord separated by diagonal webs and vertical webs. Figure 6 1plane truss trusses are frequently used to span long lengths in the place of solid web girders. These loads can be other trusses that attach by sitting on top of the girder or they may attach to the side of the girder using truss hangers. The top chord is always in compression and the bottom chord is always in tension.

Girder trusses have a long straight design. 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. Girders may also be designed to accommodate special applications or designs. Girder trusses are designed to carry additional loads other than standard roof loads.

Trusses are triangular formations of steel sections in which the members are subjected to essentially axial forces due to externally applied load. The truss plate manufacturer s engineer usually reviews and seals the individual truss designs on behalf of the truss fabricator. 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. Top general geometry for efficient structural performance the ratio of span to truss depth should be chosen in the range 10 to 15.