A Life Prediction Methodology for Thick Section Composites Used in Civil Infrastructure

As fiber-reinforced polymer (FRP) composites find application in highway bridge structures, methodologies for describing their long-term performance under service loading will be a necessity for designers. The designer of FRP bridge structures will be faced with out-of-plane damage and delamination at ply interfaces, The damage most often occurs between hybrid plys and dominates the lifetime response of a thick-section FRP structure. In this paper a model is developed to address these issues. The methodology employs the quadratic delamination initiation failure criteria, in conjunction with a delamination growth law to describe the out-of-plane damage under bending. These phenomena are combined with the critical element residual strength life prediction tool to determine remaining bending stiffness and moment capacity of a pultruded and hybrid FRP 20.3-cm-deep structural shape. The model successfully describes the onset of delamination prior to fiber failure and suggests that out-of-plane failure controls the life of the structure.