Experimental and Numerical Investigations on Seismic Behavior of Prefabricated Bridge Columns with UHPFRC Bottom Segments

The seismic performance of prefabricated segmental bridge columns (PSBCs) with ultrahigh-performance fiber-reinforced concrete (UHPFRC) bottom segments was investigated through model tests and numerical simulations in this study. Four large-scale PSBC specimens with different bottom segments were designed and tested under cyclic quasi-static loading. A novel bottom segment construction, combining a RC cast-in-place inner column and an UHPFRC external precast hollow column, was proposed to improve the energy dissipation capacity of the PSBCs. Seismic behaviors of the test specimens, including the damage pattern, hysteretic characteristics, residual displacement, joint opening, and energy dissipation capacity, were investigated. It was found that the PSBC specimens with UHPFRC bottom segments had greater lateral capacity and residual displacements than those of the specimen with the RC bottom segment, and the former exhibited minor concrete damage during the tests. The PSBC specimen with the composite bottom segment showed greater energy dissipation than other specimens, at relatively high drift levels. Detailed finite-element (FE) models were developed to predict the cyclic behavior of the PSBCs with UHPFRC bottom segments. Good agreements were observed between the FE results and the experimental results, indicating the applicability of the developed FE models. Based on the validated FE mdoels, parametric analyses were conducted to explore seismic behaviors of PSBCs with different hollow ratios and height ratios for the bottom segments. Analytical results indicated that the hollow ratio of UHPFRC bottom segments had a limited influence on the lateral capacity of the PSBC models, and the PSBC model with the bottom UHPFRC segment having a hollow ratio of 0.5 exhibited greater energy dissipation capacity. The lateral capacity and energy dissipation capacity of the PSBC models with the composite bottom segment were improved with the increase of bottom segment height, up to a 0.375 height ratio. (c) 2019 American Society of Civil Engineers.