Numerical Simulation of Reinforced Concrete Piers after Seawater Freeze-Thaw Cycles

The reinforced concrete (RC) piers of offshore bridges inevitably experience seawater freeze-thaw cycles due to the periodic movement of tides in cold climates. The damage caused by seawater freeze-thaw cycles will reduce the durability and mechanical properties of concrete, and then affect the seismic performance of RC piers. The method of seismic performance analysis on RC piers by numerical simulation is gradually emerging because the process of the conventional experiment is relatively complicated, and the heterogeneity and degradation of concrete after seawater freeze-thaw cycles should be considered. In this study, the method of meso-element equivalent and layered modeling was used to simulate a low cyclic loading test on an RC pier after seawater freeze-thaw cycles with ABAQUS software. The numerical simulation results were compared with the experimental results; the deviation value of peak load was not more than 6%, and the deviation value of peak displacement was not more than 10%. The result of the numerical simulation matched well with the experimental results, and the influence of different parameters was analyzed through the practical method of numerical simulation. It can be determined that the peak load decreased by 11%, while the peak displacement increased by 40% after 125 seawater freeze-thaw cycles. In the same 125 freeze-thaw cycles, the peak load increased by 15% and 27% while the axial compression ratio and the longitudinal reinforcement diameter increased. As the stirrup spacing of specimens decreased, the peak load remained unchanged, but the ductility coefficient of the specimens increased by 20%.