Cracking in a curved, reinforced concrete box girder bridge

A study to monitor a multi-span reinforced concrete bridge was recently completed. The bridge is curved, with a non-prismatic three-cell box cross section. Extensive field testing was performed to evaluate the causes and effects of large shear cracks. Evaluation of the test results has shown that the distribution of strains in the bridge is significantly different from those assumed in design. This paper reports on the use of finite element analysis to assist in the evaluation of the behavior. Of prime interest has been the identification of the sources of the discrepancy between the test data and the design. This work shows that it is necessary to include concrete softening due to both shear and flexural cracking. The finite element model has also been used to demonstrate that the cracks were primarily the result of temperature differentials arising from the position of the sun during the normal daily cycle.