预应力钢管高强混凝土组合桥墩抗震性能试验研究

Seismic performance of three-directional prestressed columns with a high strength concrete-filled steel tube core: An experimental study

为了提高桥墩的抗震性能和自复位性能,首先设置预制钢管高强混凝土芯柱,并对其施加竖向预应力,浇注芯柱外混凝土再采用预应力钢带施加横向约束,形成三向预应力钢管高强混凝土芯柱组合桥墩。通过对3个三向预应力钢管高强混凝土芯柱组合桥墩与3个不同预应力形式的桥墩试件的低周反复加载拟静力试验,对三向预应力钢管高强混凝土芯柱组合桥墩的受力机理、抗震性能和自复位性能等进行研究,着重分析试件裂缝的开展、破坏形态、骨架曲线、滞回曲线、刚度退化、延性、耗能性能和自复位性能。试验结果表明:相对普通钢筋混凝土桥墩,三向预应力钢管高强混凝土芯柱组合桥墩的抗震性能尤其是自复位性能得到明显的改善和提高。

In this study,a new type of three-directional prestressed bridge piers with a high-strength concrete-filled steel tube(CFST)core was introduced to improve the seismic and self-centering performances of bridge piers.The high-strength prefabricated CFST core was first set in a reinforced concrete bridge pier,and the high-strength steel rods in the CFST core were prestressed using a jack to introduce vertical prestress.Then,prestressed steel strips were applied to produce bilateral prestress,which led to a three-directional prestress.Based on the quasi-static experiments of the three new composite piers and three other specimens to compare different prestressed forms,the mechanical,seismic,and self-centering performances of these new composite piers were studied,and the crack growth,final failure patterns,skeleton curves,hysteretic curves,stiffness degradation,ductility,energy dissipation,and self-centering performance were analyzed.The experimental results indicate that the seismic performance,especially the self-centering performance of this new composite bridge pier,was significantly improved in comparison with the common reinforced concrete pier.