中文摘要：

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。

英文摘要：

In order to explore influence of the coupling effect of the compression, bending, shear and torsion on the consolidated bridge column connected with box girder in the earthquake, the quasi-static model tests of seven reinforced concrete bridge columns under the coupling effect were carried out. The different failure modes of bridge columns was determined, and the hysteretic curves and skeleton curves of shear force-displacement and torque-twist angle were analyzed. Meanwhile, the influence of parameters including torsion-bending ratio, slenderness ratio, reinforcement ratio and stirrup ratio on the bending-torsion coupling seismic performance was studied. Based on theoretical analysis and the quasi-static model tests, four-segment shear force-displacement theoretical skeleton curves and three-segment torque-twist angle theoretical skeleton curves of bridge columns were derived. The results show that theoretical skeleton curves coincide with experimental curves. And key influence factors and the coupling effect of bendingand torsion of the concr displacement theoretical of the failure section of ete ske bridge columns present in the theoretical model. The shear force- leton curve highly depends on the bending moment-curvature relation bridge column. The torsional capacity is mainly from concrete and stirrups, and the twist angle of the column top can be calculated according to the elastic twist angle of concrete bridge column and the twist angle of torsional plastic hinge. The bending- torsion coupling effect changes the seismic performance of concrete bridge columns significantly. Large torsion effect causes the failure of bridge columns before reaching the maximum flexural performance. However the torsional capacity of the concrete bridge columns decreases influenced by the bending effect. With the decrease of the slenderness ratio, the maximum shear force increases, the ultimate displacement decreases and the maximum torque remains constant. The longitudinal reinforcement ratio mainly affects the flexural capa