The different effect of cyclic loading protocol on spun pile performance

Numerical study to investigate the effect of various loading protocol to seismic performance of spun pile connection has been performed using OpenSees. Six loading protocols adopted in FEMA P440 were applied to three specimens. The study started with validation of FE model, and the model can closely simulate the experiment conducted by another researcher. The loading was presented in the form of a drift ratio, a number of cycles, and the rate of loading. It is found that different types of loading protocols affect seismic performance in terms of stiffness and strength degradation. Among six loading protocols, TP-01, as adopted in ACI 437.1R-07, give moderate results. Significant stiffness degradation was observed on hollow spun pile compare to those with concrete infill. It is found that the presence of concrete infill improves the strength of the spun pile connection by 45%. Increase the strength of concrete infill slightly improve the performance of spun pile.