Cyclic loading tests and analyses of posttensioned concrete bridge columns combining cast-in-place and precast segments

Abstract

This paper investigates the seismic performance of posttensioned concrete bridge columns combining cast-in-place and precast segments to achieve optimal response to cyclic loadings and construction. For this purpose, a monolithic bridge column (MBC), a hybrid bridge column with a combination of precast segments and a cast-in-place column base (HBC), and a precast segmental bridge column (PSBC) were designed and built. The three columns were subjected to cyclic loading to assess the seismic capacity. Experimental data showed the HBC to have better performance regarding hysteretic characteristics, energy dissipation, and stiffness degradation compared to the PSBC. The HBC and PSBC both exhibited significantly higher self-resetting capacity than the MBC. The corresponding numerical simulations were conducted based on OpenSees platform, and the results were compared with the test data. Using the validated numerical model, further parametric analyses were carried out to assess the energy dissipation capacity of the HBCs. This was found to increase with the height-to-diameter ratio of the cast-in-place column base until a certain threshold. A reasonable height-to-diameter ratio of the cast-in-place region with different axial compression and longitudinal reinforcing ratios could be defined for improving the energy dissipation capacity in seismic design of the proposed HBCs.