Low-Damage Seismic Design for Accelerated Bridge Construction

In this research, a low-damage seismic design technology has been proposed for accelerated bridge construction (ABC). ABC low damage aims to minimize, and potentially eliminate, damage in a precast bridge during an earthquake. The low-damage design uses dissipative controlled rocking (DCR) connections between the precast elements in a bridge substructure. A DCR connection replaces the traditional plastic hinge at the column-to-footing or column-to-cap beam locations. DCR combines unbonded post-tensioning and externally attached metallic dissipaters to provide self-centering and energy absorption capabilities for the bridge, respectively. In this research, a half-scale precast bent was tested under quasi-static cyclic loading to validate the concept of low-damage design. The performance of the bent was compared against an equivalent bent with emulative cast-in-place connections. Results from testing suggested high performance of the low-damage bent. Following many cycles of large drift ratios, there was no damage or residual displacement in the bent. Findings from this research were implemented in the Wigram-Magdala Link Bridge in Christchurch, New Zealand, in July 2016. The bridge remained intact during the Kaikoura Earthquake on November 14, 2016.