Design of a Triangular Cross‐Section Bridge Truss

Abstract

The structural advantages and aesthetics of a triangular cross‐section truss have long been recognized by structural engineers and architects alike. Until recently, however, it has not been considered cost‐effective to design and build this system over the traditional rectangular or two‐dimensional truss to carry heavy loadings. But with recent advances in welding techniques, the use of computer analysis methods, and the increased availability of structural tubing for truss members, the triangular cross‐section truss has seen a wide range of new applications. This paper discusses the analysis and design of this type of truss to carry highway loadings. The structural analysis program TRUSS1 by the writer, is used for the analysis and design of various truss configurations. Several primary bracing, sway bracing, and truss depth configurations are investigated, and final selection for design is based on least weight criteria. The final design conforms to the current American Association df State Highway and Transportation Officials (AASHTO) bridge specifications. The design deals with member selection considering buckling and stress constraints, joint design, and deflection criteria.