钢箱混凝土空心薄壁墩抗震性能研究

Study on Seismic Performance of Concrete-Filled Hollow Thin-Walled Square Steel Box Pier

为研究钢箱混凝土空心薄壁墩的抗震性能,采用有限元法对一跨山头桥梁模型的钢筋混凝土空心墩与截面等效的钢箱混凝土空心墩作了弹性时程分析下的墩底动力响应对比。再针对钢箱混凝土空心构件,进行低周往复作用受力分析,研究了添加PBL加劲肋对钢箱混凝土空心构件滞回曲线、骨架曲线、延性系数、耗能能力和残余变形等特性的影响规律。结果表明:钢箱混凝土空心墩在地震作用下能通过更大位移减小墩底地震内力峰值响应,相比钢筋混凝土空心墩更适合于山区桥梁;添加PBL加劲肋能减小钢箱混凝土空心构件在往复荷载作用下的损伤,改善结构受力状态,显著提升构件的水平地震抗力和延性,位移幅值越大,构件耗能能力越能得到充分发挥,且有利于震后修复和继续工作。

In order to study the seismic performance of concrete-filled hollow thin-walled square steel box pier,the dynamic response of pier bottom under elastic time history analysis is compared between reinforced concrete hollow pier of one span mountain bridge model and concrete-filled hollow thin-walled square steel box pier with equivalent section by finite element method.Then,for the concrete-filled hollow thin-walled square steel box pier,the low cycle reciprocating force analysis is carried out,and the influence law of adding PBL stiffener on the hysteretic curve,skeleton curve,ductility coefficient,energy dissipation capacity and residual deformation of steel box concrete hollow pier column is studied.The results show that the concrete-filled hollow thin-walled square steel box pier can reduce the peak response of seismic internal force at the pier bottom through greater displacement under earthquake,which is more suitable for bridges in mountainous areas than reinforced concrete hollow pier.The addition of PBL stiffener could reduce the damage of concrete-filled hollow thin-walled square steel box pier under reciprocating load,improve the stress state of the structure,and significantly provide the horizontal seismic resistance and ductility of the members.The greater the displacement amplitude is,the more the energy dissipation capacity of the members can be brought into full play,and it is conducive to post earthquake repair and continuous work.