Evaluation of the Residual Bearing Capacity of Prestressed Concrete T-Girder Bridges Based on Bending Stiffness Reduction

This paper examines the use of the measured bending stiffness reduction of a prestressed concrete bridge to evaluate its residual bearing capacity (RBC). To create a clear correlation between bending stiffness and the RBC, the extent of bridge damage is equated to the rebar area reduction in accordance with bridge design codes. The validity of the proposed model was confirmed through the experimental testing of a prestressed concrete T-girder. Moreover, the paper also addresses the impact of transverse connection damage on the measured reduction in bending stiffness for practical application. A refined measure of bending stiffness reduction is derived through the analysis of the load distribution across the bridge due to damage in transverse connections. Field testing data of a real prestressed concrete T-girder bridge from the tap-scan method demonstrate that damage in transverse connections had a few percent impact on the RBC. In light of these findings, a novel method for efficiently evaluating the RBC of prestressed concrete bridges based on the bending stiffness is formulated. Since all parameters are directly measured nondestructively in the field, the proposed method significantly diminishes the reliance on subjective expertise in RBC evaluations.