Structural behavior of CFRP wrapped circular hollow bridge piers under cyclic loading considering local buckling limit state

This research paper explores how Carbon Fiber Reinforced Polymer (CFRP) can improve the performance of circular hollow steel bridge piers when subjected to cyclic loading. According to the modern seismic code, performance-based design is a must. Performance-based design depends on various limit states. Using numerical analysis, the study focuses on the behavior of circular steel columns under axial and lateral cyclic loading, considering local buckling. Initially, a 3D finite element model is created using ABAQUS software to capture the cyclic behavior of a previously tested specimen. Then, CFRP is applied to the validated specimen's buckling-wave length to analyze the column's cyclic performance. The study assesses how the introduction of CFRP affects the established local buckling limit states of circular steel columns. The results show that strategically adding CFRP reinforcement at specific buckling-wave lengths significantly increases the column's ultimate load-carrying capacity and dissipated energy. However, it is important to note that when the buckling-wave length is one and one-half, the column reaches its yield strength before fully utilizing CFRP’s inherent strength, emphasizing the need for design optimization. Additionally, doubling the length of CFRP at the buckling-wave length is found to be crucial in enhancing load-carrying capacity and cumulative dissipated energy beyond the buckling length. The study also highlights CFRP's effectiveness in addressing elephant foot buckling.