Ultimate Flexural Capacity of a Severely Damaged Reinforced Concrete T-Girder Bridge

Abstract

Rational and precise evaluation for ultimate flexural capacity is essential for accurate prediction of the safety margin and overload capacity of existing bridges. One of the spans of a 28- year-old distressed simply supported T-girder bridge with a span of 20 m was severely damaged, and the decision to replace it with new one was made. A field destructive load test of this distressed span was performed. A nonlinear finite-element model technique was used to predict the failure load and retrace the load-versus-deflection response. The ultimate flexural capacity obtained by the destructive load test was compared with the results of a limit-states design method. The comparison revealed that the ultimate flexural capacity of the distressed bridge was more than the bending moment produced by the combined effect of self-weight and overloaded vehicles plying over it, which explains why the bridge supported overloaded vehicles for many years.