EXPERIMENTAL STUDY ON SEISMIC BEHAVIOR OF SELF-CENTERING SMA/ECC BRIDGE PIER

The seismic capability of pier column is important to the safety of the whole bridge structure. To reduce residual deformation and damage, and to resume normal functions with no or minimal repair after earthquake, an innovative pier column with self-centering capability based on Shape Memory Alloy (SMA) and Engineering Cement Composite (ECC) was proposed. In the plastic hinge zone of the self-centering pier column, the longitudinal reinforcements and concrete were replaced by SMA bars and ECC. Therefore, the self-centering capability of the pier column can be achieved through SMA with the energy dissipation capacity being improved. Damage of pier column can be reduced by ECC with strain hardening characteristics. Five specimens were produced, i.e., ordinary reinforced concrete bridge pier (R/C-BP), reinforced ECC bridge pier (R/ECC-BP), steel strands reinforced bridge pier (SS/C-BP), steel strands reinforced ECC bridge pier (SS/ECC-BP), and SMA reinforced ECC bridge pier (SMA/ECC-BP). Based on low cyclic loading tests, the failure characteristics, bearing capacity, ductility and energy dissipation capability of pier column specimens were analyzed. The test results show that the SMA material can effectively enhance the displacement ductility coefficient and improve the ductility performance of the structure, and can reduce the residual deformation of the structure. The ECC material can significantly improve the ductility of the structure and reduce the speed of cracking and increase the energy dissipation capacity of the structure. Compared with the ordinary specimen, SMA-ECC pier column was less damaged with remarkable self-centering capability. Furthermore, it also exhibit excellent ductility and seismic performance.