复杂应力状态下的钢筋混凝土桥墩抗震性能研究

文中以玉湛线高速路中实桥桥墩为原型建立桥墩三维有限元仿真模型,模拟地震组合荷载作用下桥墩结构响应,分析抗震性能影响因素及有效抗震措施。主要研究在双向地震作用、上部结构恒载活载等组合荷载作用下的结构响应基础上,桥墩弯、剪、扭复杂应力状态下的抗震性能及其影响因素,包括塑性铰区抗剪强度、墩顶位移、含箍率,以及轴压比对钢筋混凝土桥墩的抗震性能和延性水平的影响。结果表明,适当增加墩底抗剪区的箍筋配筋率或减小配筋间距均可有效增大墩底的抗剪强度;增加螺旋箍筋的配筋率可有效增加易损段的弯曲延性,达到减少震损和降低后期维护成本的目的;增加桥墩主纵筋配筋率会减小桥墩的弯曲延性,不建议用作桥墩的延性抗震设计措施。

Research on Seismic Performance for Reinforced Concrete Piers under Complex Stress Condition

A three-dimensional finite element model for a highway bridge pier is established to analyze the multi-dimensional response under earthquake and various working loads,and to study the effective seismic measures.Based on the structural response under the bi-directional seismic action and the multi-directional working loads from the superstructure,the seismic performance and its influencing factors are investigated under the complex stress condition with bending,shear and torsion.The influences of the shear strength of the plastic hinge area,the displacement of the pier top,the stirrup ratio and the axial compression ratio on the seismic performance and ductility of RC piers are studied respectively by linear derivation analysis method.The results show that properly increasing the stirrup reinforcement ratio or reducing the reinforcement spacing can effectively increase the shear strength of the key section at the bottom of the pier and reduce the possible shear damage caused by earthquake damage;increasing the configuration ratio of spiral stirrups can effectively increase the bending ductility of the vulnerable section,which can reduce the earthquake damage and the maintenance cost;increasing the main longitudinal reinforcement of the pier will reduce the bending ductility of the pier,which is not recommended to be considered in the seismic ductility measures of the pier.