Beam-Truss Model of Steel-Concrete Composite Box-Girder Bridges

Abstract

In this paper, a beam-truss model is introduced for the design analysis of composite box-girder bridges. An integrated research program for beam-truss models, including modeling implementation, analysis, and application, has been performed to exploit this powerful research and design tool. First, beam-truss models of composite box-girder bridges are implemented, and then corresponding model strategies are formulated based on classical shear–flexible grillage analysis. The calculation accuracy of the beam-truss models is then verified through comparative studies on the structural behavior of straight and curved composite, simply supported, and continuous box-girder bridges obtained using elaborate beam-truss finite-element (FE) models. Numerical analyses include modal analysis; static analysis under gravity load, prestressing load, and lane live load; and whole-process analysis considering the construction method and the long-term behavior of concrete. Finally, beam-truss models are employed for the analysis of field tests on two actual composite box-girder bridges, one straight and the other curved. It is concluded that the beam-truss model provides a reliable and powerful tool for the design analysis of composite box-girder bridges.