Research On Improvement Measures For Seismic Performance Of Precast Segmental Bridge Column

Precast segmental bridge column (PSBC) is becoming a hot spot of substructure research in recent years due to the advantages of short construction period, little impact on traffic and strong capability of self-reposition. At the same time the technique of PSBC has been used in the construction of bridge columns in some western countries. However, PSBC can only be built in regions of low seismicity because of its poor durability, large demand of seismic displacement and limited energy dissipation (ED) capacity. Therefore, to make this type of column built in high seismic regions, many structural measures for improving ductility and ED capacity have been put forward. To study the improvement level of seismic performance for PSBCs with different structural measures, this paper conducted the following research works and drew the corresponding conclusions:(1) The modeling method of numerical simulation for reinforced concrete structures was introduced in details. A three-dimensional finite element model of Cast-in-place reinforced concrete (RC) column and a model of PSBC was respectively developed based on ABAQUS platform, and was validated with the experiment results of other researchers. It was found that the results of numerical computation coincided with the test data, which proved the correctness of modeling approach.(2) Five types of PSBC models respectively with the structural method of unbonded posttensioned (PT) strands, bonded PT strands, ED bars, mortise-and-tenon (MT) joints and viscoelastic (VE) dampers were established. Quasi-static analyses were performed for the column models with unbonded PT strands, bonded PT strands, ED bars and MT joints, with the comparison of ultimate bearing capacity, hysteretic ED capacity, ductility performance and re-centering capability. Then pseudo-dynamic time-history analyses were performed for the models with unbonded PT strands, ED bars and VE dampers, with the comparison of displacement and acceleration of pier Crown.(3) By comprehensive consideration in the aspects of seismic performance, easy for construction, aesthetics and project cost, unbonded precast segmental bridge column with ED bars was recommended to be adopted in the regions of high seismicity. At last, Connection form of steel sleeve grouting was proposed to anchorage ED bars, and the reliability of steel sleeve anchoring ED bars was verified by pull-out test of steel sleeve connector.