A Two-Stage Strength Assessment Methodology for Deep Concrete Cap Beams

A significant portion of the nation’s aging bridge inventory consists of bridges with deep cap beams which were not designed to carry modern traffic loads. A strength assessment of these bridges is required for accurately predicting their load and deformation capacities. This paper proposes a two-stage strength assessment methodology for deep cap beams based on a nonlinear finite element analysis. To validate the finite element modeling approach, five pier caps experimentally investigated in the literature were analyzed. Crack patterns, load-displacement response, failure modes, and governing critical members were investigated under near collapse conditions. The complete proposed methodology was employed on a case study involving five existing bridges located in Ohio and the predicted capacities were compared with the traditional sectional and strut-and-tie methods. The proposed methodology has the potential to reduce the number of bridges found overloaded using traditional methods, resulting in significant cost savings.