Study on Economic Configuration of Flat Roofed Steel Trusses

Truss is a frame work of triangles in which members are connected with hinge joints. This structural form transfers external loads acting on the structure by developing only axial forces in the members. As minimum sections are sufficient to resist axial forces, trusses can be considered as an efficient structural form particularly for long span structures. For given span, economy of the truss depends on its configuration, panel length and height of the truss. As there are no guidelines available to fix those parameters which leads to minimum weight of the truss, an attempt was made to obtain economic configuration of all trusses. Four flat roofed Truss Configurations mainly, Warren, Pratt, Howe, N type, spans of 26 m, 30 m, 36 m 42 m and 48 m are considered for different panel lengths and heights for the study. Trusses are analyzed and designed using STAAD.Pro. and total weight of the truss is obtained. The one with minimum weight of the material is considered as economic truss. It is observed that among four configurations considered in the study, warren type is most economical for all spans.