RC桥墩弯剪破坏判别准则与抗震分析的改进模型

Discrimination Criterion Governing Flexural-shear Failure Modes and Improved Seismic Analysis Model for RC Bridge Piers

为进一步发展考虑非线性剪切效应的钢筋混凝土(RC)桥墩弯剪数值分析模型,分别基于修正的压力场理论(MCFT)和纤维梁柱单元模型计算了76个RC桥墩至极限荷载阶段时的剪切和弯曲变形,并根据两者之间的比值关系提出了桥墩弯曲-弯剪-剪切破坏模式的判别准则。根据桥墩破坏模式的不同,建立了桥墩弯剪数值分析的改进模型,以合理考虑桥墩弯曲与剪切变形间的耦合关系,并将模拟得到的桥墩滞回曲线与试验结果进行了对比。结果表明:桥墩剪切与弯曲变形的比值0.2和1.5可分别作为弯曲-弯剪-剪切破坏模式的判别标准,改进模型模拟得到的剪切及弯剪破坏RC桥墩滞回曲线与试验结果吻合良好。

In order to further develop the flexural-shear numerical analysis model for reinforced concrete（RC）bridge piers with nonlinear shear effect considered,the shear and flexural deformations of 76 RC bridge piers under ultimate loads were calculated based on the modified compression field theory（MCFT）and fiber beam-column element model respectively.And a discrimination criterion governing flexural,flexural-shear or shear failure modes of RC bridge piers was proposed by the ratio between shear and flexural deformations.An improved flexuralshear numerical analysis model for bridge pier was established according to different failure modes of the piers,which could consider the coupling relation between flexural and shear deformations of the piers.The simulated hysteretic curves by the improved flexural-shear analysis model were compared with test results.The results show that the shear to flexural deformation ratio of 0.2and 1.5could be taken as the discrimination criterion governing flexural,flexural-shear,and shear failure modes of the piers.Also,the simulated hysteretic curves of the bridge piers withshear and flexural-shear failure modes by the improved analysis model agree well with test results.