Experimental Study of Posttensioned Precast Segmental CFDST Columns under Cyclic Loading

The conventional precast segmental concrete column may suffer severe damage in concrete segments and yield significant residual deformation when subjected to a strong earthquake. To achieve the goal of low-damage seismic design for accelerated bridge construction in high seismicity areas, a precast column using concrete-filled double-skin steel tube (CFDST) segments is a promising candidate. In this study, an innovative posttensioned precast segmental CFDST (PTPS-CFDST) column is proposed, and four PTPS-CFDST column specimens considering the effects of external energy dissipation (ED) devices and initial prestressing forces were tested under lateral cyclic loading to explore their seismic performance. The mechanical features of the testing PTPS-CFDST columns including damage pattern, hysteretic characteristics, ED capacity, prestressing force variation, residual displacements, joint opening, curvature distribution, and concentrated rotations were compared and discussed. Testing results revealed that the PTPS-CFDST column has good seismic performance, good self-centering capacity, and minor seismic damage; the column deforms with multiple joint rotations; the reasonably arranged ED devices can effectively improve the ED performance; and a relatively high prestressing force enhances the strength and stiffness of the column. This study achieves a deeper understanding of the seismic performance of the innovative PTPS-CFDST column, which may provide references for the seismic design of this new type of bridge piers.