97-0014 Seismic Resistance of Bridge Piers Based on Damage Avoidance Design J.B. Mander and C-T. Cheng 1997 University at Buffalo 144 PB98-144223 25 This report concerns the development of a new seismic design paradigm called Damage Avoidance Design (DAD). Construction of bridges piers is based on modular (precast) beam and column elements that are free to rock under large lateral loads. Damage is avoided by special detailing of the connections. If desired, the lateral strength can be enhanced by using supplementary unbounded prestressing tendons. Due to the use of specially detailed steel-steel interfaces, the columns are expected to behave in a bilinear fashion with neither damage nor degradation in strength and stiffness. To validate the proposed design philosophy, the seismic performance of a near full-size precast concrete rocking column substructure 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 many cycles of loading. A complete force-deformation model for the rocking column accounting for: structural flexibility (pre-rocking), rigid body kinematics (post-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. (Adapted from authors' abstract). Capacity design. Damage avoidance design. Reinforced concrete bridge piers. Reinforcement. Detailing. Precast concrete. Rocking piers. Design methods. Experimental tests. Steel steel interfaces. Earthquake resistant design.