Seismic Repair Assessment of Hybrid Sliding-Rocking Bridge Columns through Integrated Experimentation and Expert Panel Solicitation

Due to the large number of bridges that will need upgrade, retrofit, or replacement in coming years, there is an increasing need for seismic bridge design techniques that are compatible with accelerated bridge construction (ABC). This study examines one promising column design strategy, the hybrid sliding-rocking (HSR) system, which incorporates precast segmental columns with unbonded post-tensioning, and both rocking and sliding joints. The goal of the study is to evaluate damage states and identify repair strategies for these columns through integrated experimental testing and expert panel solicitation. The expert panel methods use two different established group solicitation techniques to identify seismic repair objectives for bridges and to propose repair strategies for HSR columns that are consistent with these objectives. In parallel, a series of large-scale pseudo-static cyclic tests at the Texas A&M University Center for Infrastructure Renewal are carried out on a HSR column. The column is then repaired, based on the guidance of the expert panel, and tested again. The results show that the column experiences limited damage, consisting of spalling of concrete near the rocking joints, and up to 4% drift (consistent with hazard levels with return periods greater than 4,500 years). This damage can be repaired with grout and a carbon fiber reinforced polymer jacket. Most of the residual drift can be recovered by recentering sliding joints. The panel found that the HSR columns were less damageable than conventional columns and promising for application in high seismicity areas. The damage states and repair strategies identified will facilitate future performance-based engineering assessments of the new HSR columns. (C) 2020 American Society of Civil Engineers.