Stress Distribution in Continuous Thin-Walled Multi-Cell Box Girder Bridges

Abstract

Several researchers have studied stresses in thin-walled box girder bridges but stress distribution in continuous thin-walled multi-cell box girder bridges has not received much attention in published literature. Hence, this research investigated stress distribution in continuous thin-walled multi-cell box girder bridges. Analysis of box girder bridges is complex and the complexity is even more when the box girder is continuous with multi-cells. The modern trend in the analysis is to program the more straightforward methods for ease of computer application. Therefore, the analytical tool for this study is a MATLAB program developed by the authors for the finite strip analysis of continuous thin-walled box girder bridges. Numerical study on stress distribution was carried out on two box girder bridges. The first was a simply supported box girder bridge subjected to eight point loads which was used primarily for comparison with literature. The result obtained by the program was in good agreement with literature. The second was a continuous thin-walled multi-cell box girder bridge subjected to vehicular loads and self weight. The beam theory solution was also used for comparison of results in both cases. The study concluded that under symmetrical loading the longitudinal normal stress, shear stress at end supports, transverse bending moment, and longitudinal bending moment are substantial while the transverse normal stress and twisting moment are negligible. The program can, therefore, be used in practice to determine stress distributions of box girders and prismatic folded plates. However, classical finite strip underestimates stress values at points of high stress concentration.

http://dx.doi.org/10.4314/njt.v33i4.5