Quasi-Static Cyclic Testing of Pier-Pile Connection with Replaceable Bars

Abstract

This research proposes a post-tensioned rocking solution referred to as dissipative controlled rocking (DCR) connection for bridge columns supported on monopile foundations. The DCR connection is a low-damage system that replaces the plastic hinge mechanism in a column and aims to minimise and potentially eliminate the repair time and costs after an earthquake. A DCR bridge system combines unbonded post-tensioning and replaceable dissipaters to provide self-centring and energy absorption capabilities, respectively. In this research, a pier supported on a monopile, scaled to one-third, was tested under quasi-static cyclic loading to validate the lateral seismic response of a DCR bridge column with the contribution of the soil–structure interaction. When developing the details for the DCR connection, particular emphasis was made on utilising conventional construction materials and forms that yield a similar construction cost to traditional cast-in-situ construction. Nevertheless, the proposed DCR connection can be easily and quickly repaired or replaced after a significant seismic event. The performance of the pier was compared against a benchmark structure with an emulative connection type that resembles a monolithic cast-in-place joint. Results from testing suggest a greater better performance of the low-damage DCR column. The dynamic response of the DCR column built on a flexible foundation differed from that of a fixed-base structure, primarily due to the energy dissipation capability of the flexibly supported structure. Flexibility in the soil foundation increased the structural period of the structure and reduced the seismic response of the DCR column. Damage to the DCR column was limited to concrete crushing at the rocking interface, which proved easily repairable. In contrast, the pier with an emulative connection developed plastic hinging at the bottom of the column, which was nonrepairable.