Determining the Shear and Flexural Strength of Fire Damaged Steel Girders: Harrisburg Bridge Fire Case Study

Abstract

Bridges that experience fire damage are liable to collapse and generate massive costs from detours and repairs. The Harrisburg Bridge fire caused out of plane web deformations in the steel plate girders in span 2 and led to the replacement of the entire span. Both shear and flexural buckling are possible causes for these deformations. This thesis aims to determine the shear and flexural residual postbuckling strength remaining in the girders using a finite element analysis. This study found that the girders retained over 20% of their postbuckling shear strength in all cases. Based on the loading capacity and demand of the girders, flexural buckling was the controlling limit state.