Experimental testing and modeling of precast segmental bridge columns with hybrid normal- and high-strength steel rebars

Precast segmental bridge columns (PSBCs) have significant advantages, including faster construction speed and lower environmental impacts, over cast-in-place bridge columns. Traditional PSBCs usually employ normal-strength steel rebars as longitudinal reinforcement. Hence, it is named the NSR-PSBC herein. In this paper, a novel PSBC, named hybrid-reinforced PSBC (HR-PSBC), is developed. The HR-PSBC utilizes hybrid normal- and high-strength steel rebars to improve the seismic response of PSBCs. The main contributions of this study include: (1) large-scale cyclic tests were conducted to compare the seismic performance of the HR-PSBC with the NSR-PSBC; and (2) a novel and computationally efficient finite element model for the HR-PSBC was developed. The test results demonstrated that the hybrid reinforcement employed in the HR-PSBC was very effective in improving the post-yield stiffness, self-centering capacity, ductility and load-carrying capacity of the bridge column. These test results were further used to verify the accuracy of the proposed finite element model. It was found that the numerical model was able to provide satisfactory predictions of both global and localized responses of the PSBCs. Based on the results presented in this paper, it is concluded that the HR-PSBC can be a promising alternative to traditional NSR-PSBCs and cast-in-place bridge columns, and the proposed numerical modeling method can be a suitable tool for design-oriented studies of the NSR- and HR-PSBCs.