Seismic strengthening of bond-critical regions in wall-type bridge piers using active confinement -

Abstract

Active confinement by means of pre-tensioned steel anchor rods was used in this investigation for bond strengthening of lap spliced reinforcement and for improving the seismic performance of wall-type bridge piers. As-built and strengthened representative pier specimens with lap spliced reinforcement within the critical hinging region were tested under large drift reversals. The test parameters included pier longitudinal reinforcement ratio, diameter of the spliced bars, and configuration of the pre-tensioned steel anchor rods. The strengthened columns developed enhanced bond resistance and low bond degradation of the spliced bars, increases in the lateral load and drift capacities, and much less pinching in the lateral load-drift response when compared with the as-built specimens. A design approach is proposed for evaluating the active lateral pressure required for adequate bond strengthening.