Residual Displacements of Concrete Bridge Piers Subjected to Near Field Earthquakes

The objective of this research is to find a way to reduce residual displacements of reinforced concrete (RC) bridge piers after earthquake excitations. Because prestressed concrete (PC) members usually show recovery from elastic stiffness during unloading, this study proposes the possibility of using PC to minimize the residual displacements. Prestressed members, however, will have reduced ductility. Therefore, this research examines a new technique that employs partially prestressed concrete (PPC) for the bridge piers in an effort to take advantage of the positive features of both RC and PC. An extensive experimental program, in the form of reversed cyclic loading and pseudo-dynamic tests, was carried out. The experimental variables include the relative ratio of prestressing tendons to non-prestressing reinforcement and flexural to shear capacities. Based on the test results, the inelastic response behavior of PPC bridge piers was substantially clarified. Additionally, the merits and demerits of their use were clearly identified. The study revealed that employing prestressing tendons in RC bridge piers could result in subsequent reductions of residual displacements, restrain-associated cracking, and enhanced concrete shear strength after earthquake excitations.