Investigation On Seismic Performance Of Precast Segmental Post-tensioned Concrete Hollow Columns

Segmental precast column construction has been proved to be an efficient solu-tion in accelerating bridge construction and minimizing traffic disruption. However,knowledge of the behavior and performance of precast bridge columns and theirconnections during earthquakes is lacking, and consequently their widespread use inhigh seismic hazard regions is yet to be realized. The purpose of this study was toinvestigate the performance of unbonded post-tensioned precast concrete segmentalbridge hollow columns under simulated lateral seismic loading.This dissertation is supported by Natural Science Foundation of Hebei Province.The main work of this dissertation is described as followed:(1)Based on the comprehensive reading and understanding of related literatures,the present and the future application situation of precast segmental bridge columns,the experimental and analytical research results of of precast segmental constructiontechnology of prestressed concrete bridge columns, were reviewed and summarized．(2)Four large scale hollow column specimens were designed and tested undersimulated lateral seismic loading, two specimens of which were precast segmentalhollow columns and others were cast-in-place hollow column．Through pseudo-statictest of the four concrete hollow columns, the development rule of the failure mode,the hysteresis curve, the skeleton curve, the residual displacement, the distribution ofcurvature, the energy-dissipation ability, the viscous damping ratio and the openingof the segmental joints were gained．And the likenesses and differences of theseismic performance of concrete hollow columns, unbonded post-tensioning pre-stressing hollow columns and the precast segmental hollow columns under cyclicloading were also achieved．(3) Using the OpenSees, a detailed two dimensional fiber element model is de-veloped. The finite element model was validated by good agreement between thesimulated and experimental results. A parametric study was conducted utilizing thedeveloped model to investigate the seismic responses of the hollow bridge columns. Investigated parameters include axial dead load ratio, longitudinal reinforcement ratio,ratio of post-tensioning steel, the initial tension force, the arrangement of prestressedtendons, the ED(energy dissipation) bar ratio, the length of ED bar.(4)Furthermore, seismic responses of the hollow columns subjected to earth-quake excitations are investigated with nonlinear dynamic time-history analysismethod. A parametric study is conducted to examine the seismic performance of theproposed precast segmental hollow columns with different design parameters.