近、远场地震下深水桥墩动力响应特性对比研究

发布时间：2019-05-27 03:50

【摘要】：以某典型铁路深水桥梁等效单墩模型为对象,采用基于流固耦合理论的势流体计算方法,首次对近、远场地震作用下等效单墩结构振动特性及动力响应进行对比分析。结果表明,动水环境的存在会改变桥墩振动特性,随水深增加桥墩自振周期不断增大,30 m水深时第一阶周期增长率达10.4%。墩周动水压力呈抛物线型分布,近场地震下大于远场地震,二者差别随水深增加而增大。近、远场地震下桥墩结构的动力响应存在明显差别,较无水环境,近场地震下墩顶位移、墩底弯矩及剪力峰值分别增大34.5%、37.8%及51.3%;远场地震下三项指标分别增大17.0%、21.8%及40.0%,具有明显速度脉冲的近场地震下结构动力响应显著大于远场地震。具有速度脉冲的近场地震破坏能力更强,在近断层区深水桥梁抗震设计中应特别重视。
[Abstract]:Taking the equivalent single pier model of a typical railway deep water bridge as the object, the vibration characteristics and dynamic response of the equivalent single pier structure under the action of near and far field earthquakes are compared and analyzed for the first time by using the potential fluid calculation method based on fluid-solid coupling theory. The results show that the existence of dynamic water environment will change the vibration characteristics of piers, and the natural vibration period of piers increases with the increase of water depth, and the growth rate of the first order period is 10.4% at 30 m water depth. The dynamic water pressure around the pier is parabola distribution, which is larger than that of the far field earthquake under the near field earthquake, and the difference between the two increases with the increase of the water depth. The dynamic response of pier structure is obviously different from that of far-field earthquake, which is 34.5%, 37.8% and 51.3% higher than that of anhydrous environment. The displacement of pier top, bending moment and shear force at the bottom of pier under near-field earthquake are 34.5%, 37.8% and 51.3%, respectively. The three indexes increased by 17.0%, 21.8% and 40.0% respectively under the far-field earthquake. The dynamic response of the structure in the near-field earthquake with obvious velocity pulse was significantly larger than that in the far-field earthquake. The near-field seismic damage ability with velocity pulse is stronger, so special attention should be paid to the seismic design of deep-water bridges in the near-fault area.
【作者单位】：北京交通大学土木建筑工程学院;
【基金】：国家自然科学基金(51378050) 高等学校学科创新引智计划(B13002) 中国铁路总公司重大课题(2013G002-A-3) 中央高校基本科研业务费(2014JBM094) 国家山区公路工程技术研究中心开放基金(gsgzj-2011-12)
【分类号】：U443.22;U441.3

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