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为了研究地震作用下压弯剪扭耦合作用对桥梁中墩梁固结墩的影响规律,进行了7根压弯剪扭耦合作用下钢筋混凝土桥墩的拟静力试验,确定了桥墩的不同破坏模式,给出了桥墩的剪力-位移和扭矩-扭转角滞回曲线和骨架曲线,分析确定了扭弯比、长细比、纵筋配筋率和箍筋配筋率等参量对桥墩弯扭耦合抗震性能的影响。基于理论分析和拟静力试验,给出了四线式剪力-位移骨架曲线和三线式扭矩-扭转角骨架曲线的理论模型。研究结果表明:理论骨架曲线和试验曲线吻合较好;理论模型揭示了钢筋混凝土桥墩弯曲和扭转的关键影响因素及耦合效应,其中剪力-位移理论骨架曲线主要取决于桥墩破坏截面的弯矩-曲率关系,扭转承载力主要来自于混凝土和箍筋2个部分,墩顶扭转角可以根据混凝土桥墩的弹性扭转角和扭转塑性铰的扭转角叠加计算;弯扭耦合效应会造成混凝土桥墩抗震性能发生明显的变化,较大的扭转效应会使桥墩在达到最大抗弯性能前发生破坏,而弯曲效应会大幅降低桥墩的抗扭承载力;随着长细比的减小,最大剪力增加,极限位移减小,最大扭距基本不变;纵筋率主要影响混凝土桥墩的抗弯承载力,对抗扭性能影响不明显,箍筋率主要影响桥墩的抗扭性能;工程中应采用考虑弯扭耦合的方法进行抗震设计。
In order to study the influence of shear-torsion coupling of compression and bending under seismic load on the consolidation pier of bridge pier, the pseudo-static tests of seven reinforced concrete piers under the coupled buckling of shear and torsion are carried out and the different failure modes The shear-displacement and torsional-torsional hysteresis curves and the skeleton curves of piers are given. The parameters of torsion-bending ratio, slenderness ratio, reinforcement ratio of longitudinal reinforcement and stirrup ratio of reinforcement are analyzed to determine the bending moment Influence of Coupling Seismic Performance. Based on theoretical analysis and quasi-static tests, theoretical models of four-wire shear-displacement skeleton curves and three-wire torsion-torsional skeleton curves are given. The results show that the theoretical framework curve is in good agreement with the experimental curve. The theoretical model reveals the key factors affecting the bending and torsion of reinforced concrete piers and the coupling effect. The shear-displacement theoretical skeleton curve mainly depends on the bending moment- The relation between curvature and torsional load is mainly from two parts of concrete and stirrups. The torsional angle of pier can be calculated by the superposition of the torsional angle of torsion and torsional plastic hinge of piers. The coupling effect of bending and torsion can cause the seismic behavior of concrete piers. Significant changes in the larger torsional effect will make the bridge pier in the maximum flexural capacity before the failure occurred, and the bending effect will greatly reduce the torsion bearing capacity of piers; with the slenderness ratio decreases, the maximum shear increases, the limit The displacement is reduced, the maximum torque is basically the same; the longitudinal reinforcement rate mainly affects the flexural capacity of concrete piers, the impact on the torsional performance is not obvious, the stirrup rate mainly affects the torsional resistance of the piers; engineering should consider the bending and torsional coupling The method of seismic design.