近、远场强震下深水桥墩的非线性动力响应特性

发布时间：2018-06-18 17:51

本文选题：桥梁工程 + 深水桥墩　；参考：《华中科技大学学报(自然科学版)》2017年08期

【摘要】：以深水桥梁的两座桥墩为研究对象,考虑混凝土的非线性力学行为,以可有效计入墩-水流固耦合效应的势流体完全数值法为基础建立势流体模型,并引入动水压力简化算法建立附加质量模型.讨论了墩周水域范围及势流体单元尺寸的合理取值,验证了简化算法在深水桥墩非线性动力分析中的有效性.对比讨论了弹性模型、非线性模型动力响应的差别,对比了近、远场地震下深水桥墩非线性动力响应的差异及分布特征.研究结果表明:当地震动峰值加速度(P_(PGA))较小时,桥墩非线性模型与弹性模型的动力响应相一致;随P_(PGA)的增大,非线性模型的墩底弯矩、剪力均小于弹性模型,说明强震下桥墩会进入开裂甚至弹塑性状态,其力学行为与弹性模型差别明显,应该考虑其在强震下潜在的非线性动力行为.近场地震下,深水桥墩的动力响应明显高于远场,墩底弯矩均值分别比远场地震下大80.4%和34.4%,剪力均值分别大23.7%和28.9%,表明近场地震下桥墩会进入更强的非线性状态,对近断层区深水桥梁的抗震设计提出了更高的要求.
[Abstract]:Taking the two piers of deep water bridge as the research object, considering the nonlinear mechanical behavior of concrete, the potential fluid model is established based on the full numerical method of potential fluid which can effectively take into account the coupling effect between pier and flow. An additional mass model is established by introducing the simplified algorithm of hydrodynamic pressure. The reasonable values of the water area around the pier and the size of the potential fluid unit are discussed, and the validity of the simplified algorithm in nonlinear dynamic analysis of deep water pier is verified. The difference of dynamic response between elastic model and nonlinear model is discussed, and the difference and distribution of nonlinear dynamic response of deep water pier under near and far field earthquake are compared. The results show that when the peak acceleration of local vibration is small, the dynamic response of the nonlinear model is consistent with that of the elastic model, and the bending moment and shear force of the nonlinear model are smaller than that of the elastic model. The results show that the pier will be cracked or even elastic-plastic under strong earthquake, and its mechanical behavior is obviously different from that of elastic model, so the potential nonlinear dynamic behavior of pier under strong earthquake should be considered. Under near field earthquake, the dynamic response of deep water pier is obviously higher than that of far field, the mean bending moment of pier bottom is 80.4% and 34. 4% larger than that of far field earthquake, and the mean value of shear force is 23. 7% and 28. 9% respectively, which indicates that the pier will enter a stronger nonlinear state under near field earthquake. Higher requirements for seismic design of deep water bridges near faults are put forward.
【作者单位】：北京交通大学土木建筑工程学院;中国市政工程西北设计研究院有限公司;
【基金】：国家自然科学基金资助项目(51378050) 高等学校学科创新引智计划资助项目(B13002) 中国铁路总公司重大课题资助项目(2013G002-A-3) 中央高校基本科研业务费专项资金资助项目(2016JBM044)
【分类号】：U442.55

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