A life prediction methodology for thick section composites used in civil infrastructure

As fiber-reinforced polymer (FRP) composites find application in highway br idge structures, methodologies for describing their long-term performance u nder 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 dom inates the lifetime response of a thick-section FRP structure. In this pape r 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 li fe prediction tool to determine remaining bending stiffness and moment capa city of a pultruded and hybrid FRP 20.3-cm-deep structural shape. The model successfully describes the onset of delamination prior to fiber failure an d suggests that out-of-plane failure controls the life of the structure.