Seismic resistance of bridge piers based on damage avoidance design

ABSTRACT

Current seismic resistant design practice is based on economic (limited strength) and life safety (large displacement capacity) considerrations. The seismic design philosophy that seeks to achieve these objectives is based on ductile detailing of plastic hinge regions. For a given pushover curve and effective viscous damping, the expected seismic displacement may be predicted by comparing it to the elastic desing spectra (demand). To valide the proposed design philosophy, the seismic performance of a near full-size precast concrete rocking column sbstructure was investigated. Under large lateral (rocking) displacements, no damage to either the concrete column connection or foundation was observed. The strength and stiffness was observed to remain the same after mannny cycles of loading. A complete force-deformation model for the rocking column accounting for structural flexibility (pre-rocking), rigid body kinematics (pos-rocking) and the prestressing action of the tendons is proposed. Good agreement between the predictive theory and the experimentally observed force-deformation results was demonstrated.