弯扭耦合效应下混凝土桥墩的抗震性能

发布时间：2018-08-16 16:51

【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。
[Abstract]:In order to study the influence of the coupling of compression, bending, shear and torsion on the consolidation piers of the bridge, the quasi-static tests of 7 reinforced concrete piers under the coupling of compression, bending, shear and torsion are carried out, and the different failure modes of the bridge piers are determined. The shear displacement torsion angle hysteretic curve and skeleton curve of the pier are given. The effects of torsional / bending ratio aspect ratio longitudinal reinforcement ratio and stirrups ratio on the flexural and torsional coupling seismic behavior of the pier are analyzed. Based on theoretical analysis and quasi-static test, the theoretical models of four-wire shear-displacement skeleton curve and three-wire torque-torsional angle skeleton curve are presented. The results show that the theoretical skeleton curve is in good agreement with the experimental curve, and the theoretical model reveals the key influencing factors and coupling effects of the bending and torsion of reinforced concrete pier. The shear displacement theory skeleton curve mainly depends on the moment-curvature relation of pier failure section, and the torsional bearing capacity mainly comes from two parts: concrete and stirrups. The torsional angle at the top of the pier can be calculated according to the elastic torsion angle of the concrete pier and the torsional angle of the torsional plastic hinge, and the coupling effect of bending and torsion will cause obvious changes in the seismic behavior of the concrete pier. The larger torsional effect will cause the pier to destroy before reaching the maximum bending performance, while the bending effect will greatly reduce the torsional bearing capacity of the pier, with the decrease of the slenderness ratio, the maximum shear force will increase, the limit displacement will decrease, and the maximum torsional distance will not be changed. The longitudinal reinforcement ratio mainly affects the flexural bearing capacity of concrete pier, but the effect of resisting torsional behavior is not obvious, the stirrups ratio mainly affects the torsional performance of the bridge pier, and the method of considering the coupling of bending and torsion should be used in the seismic design of the bridge pier.
【作者单位】：广州大学土木工程学院;
【基金】：国家自然科学基金项目(51308137,51378133) 广东省自然科学基金项目(2014A030313530) 广州市科技计划项目(201607010094) 广州市属高校“羊城学者”科研项目(1201541551)
【分类号】：U442.55;U443.22

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