Experimental study on the seismic behavior of RC columns improved with central large-diameter butted steel rods

Abstract A reinforced concrete (RC) column improved with central large-diameter butted steel rods (CLBSR column) has been proposed to increase the limit value of the axial compression ratio. This paper presents the seismic behavior analysis of CLBSR columns subjected to low-cycle reciprocating loading. The CLBSR columns were also compared with the RC column improved with central large-diameter steel rods (CLSR column) and the RC column improved with central reinforcement bars (CRB column) under the same experimental conditions. The typical failure modes, hysteretic curves, skeleton curves, stiffness degradation, and energy dissipation capacity were all investigated. The improved PARK damage model obtained the corresponding relationships between the damage indices and the damage state of each column. The test results indicated that the CLBSR columns and CLSR columns had similar seismic behavior, but were slightly inferior to the CRB columns. Overall, the butt joint of large-diameter steel rods had little effect on the seismic behavior.

摘要：为提升轴压比限值，本文提出一种采用中央大直径对接钢杆增强的钢筋混凝土（RC）柱（CLBSR柱）。针对低周往复荷载作用下的CLBSR柱开展抗震性能分析，并在相同试验条件下，将其与中央大直径钢杆增强钢筋混凝土柱（CLSR柱）以及中央配筋钢筋混凝土柱（CRB柱）进行对比研究。研究内容涵盖典型破坏模式、滞回曲线、骨架曲线、刚度退化特性及耗能能力；通过改进的PARK损伤模型（PARK damage model），建立了各柱的损伤指数与损伤状态之间的对应关系。试验结果表明，CLBSR柱与CLSR柱的抗震性能相近，但略逊于CRB柱；总体而言，大直径钢杆的对接接头对柱体抗震性能影响极小。