Analytical investigation of multi-joint rotation behavior of PTPS-CFDST column under lateral loading

Abstract

The post-tensioned precast segmental concrete-filled double-skin steel tube (PTPS-CFDST) column is an innovative composite column that has recently been proposed and verified to exhibit excellent seismic resilience performance, being a promising solution for low-damage seismic design in accelerated bridge construction. Under lateral loading, this type of new column behaves with multiple joint rotations with laterally unconstrained post-tensioned (PT) tendons, which cannot be accurately predicted by the existing analytical models. This study firstly presents a new multi-joint rotation analytical model for the PTPS-CFDST column under lateral push-over loading, with the positional influence of PT tendons considered. The proposed model is then validated against experimental and numerical results, demonstrating its accurate prediction of lateral force capacity, global column deformation, and local joint openings. In addition, a comparison between the one-, two- and three-joint analytical models is conducted, and the results reveal that the two- and three-joint analytical models achieve accurate results. Finally, parametric studies considering the initial prestressing force, thickness of steel tube and hollow ratio are performed, which further validates the accuracy, applicability, and versatility of the proposed model. This research enhances the analytical understanding of the multi-joint rotation behavior of the PTPS-CFDST column, which may provide references for the seismic design of this new type of column.