Performance Based Research On The Seismic Theory And Test Of New Self-centering Pier

The structural components, mechanical performance, analytical theory and designmethod with respect to residual deformation of the newly developed self-centering pier(SCP) is studied based on post-earthquake performance. The residual deformation, struc-tural components, flexural capacity, lateral stiffness, hysteresis characteristics, dynamiccharacteristics and design method is discussed by theoretical analysis, numerical simu-lation and a series of experimental studies. The main work and signifcant contributionsare as follows.(1) The residual deformation with respect to coeffcient of ductility of pier is inves-tigated. The residual deformation that is a mechanical index of post-earthquake perfor-mance of self-centering pier should be incorporated in the seismic design of pier.(2) The general basic structure of the self-centering pier is proposed. The self-centering pier consists of four basic components including load bearing (LB) unit, self-centering (SC) unit, energy dissipater (ED) and joint (J). The flexural capacity and lateralstiffness of self-centering pier are derived analytically. The analytical formula of intrin-sic lateral stiffness, which quantifcationally reveals the influence from stiffness of LBunit, stiffness of ED, stiffness of SC unit, geometry of SCP and arrangement of ED, forself-centering pier is found. Self-centering3steps (SC3S) design method is proposed forengineering practice.(3) A series of experiments of the self-centering pier are conducted. With respect toa traditional ductile pier,3types of SCP structure are designed including single SCP withInternal Energy Dissipater (I-ED), single SCP with External Energy Dissipater (E-ED)and frame made of double SCPs with External Energy Dissipater. The SCPs are testedpseudo-statically under cyclic lateral load. The bearing capacities, stiffness, hysteresischaracteristics, residual deformation of the SCP structure and the mechanical contributionof all basic components are investigated.(4) The fber beam FEM model of self-centering pier (SCP-Fiber) is establishedbased on Opensees. The pseudo-static calculation results of SCP-Fiber model undercyclic lateral load are compared with the results of the test results. The SCP-Fiber re-sults match the test results in general and the differences between them are discussed. It shows that the established SCP-Fiber model could reflect the structure properties andhysteresis characteristics etc. of self-centering pier. Based on the validation by the SCPtests, more SCP-Fiber models with different parameters are established and their seis-mic responses with respect to12selected earthquake records are investigated by dynamictime-history analysis. The seismic responses of SCPs with different basic periods areconcluded as the displacement response spectrum, acceleration response spectrum andEnergy Absorption spectrum. The research shows that the self-centering pier possessesmuch better seismic resistant capacities including almost the same bearing capacity, later-al stiffness, hysteresis characteristics and more signifcant self-centering capacity whicheliminates the residual deformation.