Parameter identification of hysteretic model of UHPC-connected precast segmental columns under cyclic loading

Due to their numerous advantages, precast segmental columns have emerged as an important development di-rection in bridge engineering. Understanding and researching their hysteretic characteristics holds great sig-nificance. Precast columns connected with UHPC achieve performance similar to cast-in-place (CIP) monolithic columns, making them suitable for use in constructing bridges located in high seismic regions. In this study, the Bouc-Wen-Baber-Noori (BWBN) model was employed to characterize the hysteretic behaviors of UHPC-connected precast segmental columns, considering strength degradation, stiffness degradation, and pinching effects. The Nelder-Mead simplex (NMS) algorithm was utilized to identify the parameters of the BWBN model, demonstrating its computational efficiency. The proposed parameter identification method was validated using experimental data derived from cyclic loading tests performed on five UHPC-connected precast segmental col-umns of three structural types. Comparative analyses encompassing force-displacement relationship, residual drift and energy consumption convincingly affirmed the applicability and precision of the proposed method for UHPC-connected precast segmental columns.