ABSTRACT
Girder bridges are structurally the simplest and the most commonly used in short-to-medium span bridges. An I-section is the simplest and most eective solid section of resisting bending and shear. Figures 4.1 and 4.2 show a steel-concrete composite I-girder bridge under construction and completion, respectively. In this chapter, straight steel-concrete composite I-girder bridges are discussed. Materials and components of I-section girders are described. Design guidelines for section proportion, span con-guration, girder spacing, diaphragms and cross frames, lateral bracings, stieners, and shear connectors are presented. A design example of a three-span continuous composite girder bridge is given to illustrate the design procedure. For a more detailed discussion, reference may be made to texts by Xanthakos (1994), Taly (1997), FHWA (2003), Unsworth (2010), Barker and Puckett (2011), and NSBA (2012). e basic steel design theory is presented in Chapter 14 of Bridge Engineering Handbook, Second Edition: Fundamentals.
