Multi-span Horizontal Structures

Abstract

In this chapter, we discuss the role of analysis in the structural engineering process for multi-span horizontal structures such as bridges. Typical examples of a girder bridge, an arch bridge, and a cable-stayed bridge are shown in Fig. 13.1. Multi-span girders are actually variable depth horizontal beams. They are used extensively in medium span highway bridge systems. Arch and cable-stayed structures are efficient for spans ranging up to 1000 m.

Chapters 9 and 10 dealt with analysis methods for indeterminate structures. Some of the analytical results presented in those chapters are utilized here to estimate critical loading patterns. Most of the analysis effort required in the engineering process is related to determining the maximum values of bending moment, axial force, and shear corresponding to the typical bridge loadings. Establishing these values for indeterminate structures requires a considerable amount of computational effort. In what follows, we illustrate this computational process for different types of bridges such as continuous girder, arch, and cable-stayed schemes using a commercial structural analysis software system.