基于动水压力的斜拉桥地震反应分析
发布时间：2018-07-28 20:27
【摘要】：近年来,随着我国交通网络的不断完善,相继出现了很多在建和拟建的深水桥梁。在地震作用下,深水桥梁下部结构的运动会引起其周围水体产生辐射波浪运动,且由于结构和水体之间的相对运动,在桥梁的下部结构上将作用有动水压力,该动水压力对结构自身的动力特性和动力响应有很大影响。因此充分认识动水压力对斜拉桥结构地震动力响应的影响,对于深水桥梁的抗震设计及安全评估具有重要的意义。本文的研究内容和结论主要有下述几个方面:1、利用Morison方程法,以附加质量考虑动水对桥墩和桩基础的影响,采用有限元软件Midas建立了东沙特大桥的有限元数值分析模型,分别就有无动水作用的情形进行动力特性分析,结果表明动水作用使得斜拉桥的自振频率减小。2、对东沙特大桥有无动水作用两种情形进行了纵向+竖向和横向+竖向两种工况下的反应谱分析和时程分析,结果表明动水对斜拉桥结构各关键点位置的位移和关键截面的内力有很大影响。3、利用大质量法对东沙特大桥有无动水作用两种情形进行了行波效应分析,探讨研究了非一致激励对斜拉桥结构动力响应的影响规律,并与一致激励时的计算结果进行对比。结果表明考虑行波效应后结构的动力响应减小,且响应结果都随着波速的增加而逐渐趋于一致激励的结果;行波效应作用下随着地震波视波速的不同水体对斜拉桥的地震响应的影响也是不同的,且一致激励和行波激励时水体对斜拉桥的地震响应的影响有所差异。4、通过在东沙特大桥上安装粘滞阻尼器,研究了粘滞阻尼器的阻尼系数C和速度指数α的变化对斜拉桥结构动力响应的影响规律。研究发现选取适当的阻尼器参数取值,可以显著地减小斜拉桥主塔的塔底弯矩以及各关键点位置的位移;综合考虑主塔塔底弯矩、各关键点位置的纵桥向位移以及动水压力的影响,建议将阻尼器的阻尼系数设置为14000k N·s/m,速度指数设置为0.35。
[Abstract]:In recent years, with the continuous improvement of China's transportation network, there have been many deep-water bridges under construction and proposed. Under earthquake action, the motion of the substructure of deep water bridge will cause the radiation wave motion in the surrounding water body, and because of the relative motion between the structure and the water body, there will be dynamic water pressure on the substructure of the bridge. The hydrodynamic pressure has great influence on the dynamic characteristics and dynamic response of the structure itself. Therefore, it is of great significance for seismic design and safety assessment of deep water bridges to fully understand the influence of dynamic water pressure on the seismic dynamic response of cable-stayed bridges. The main contents and conclusions of this paper are as follows: 1. By using Morison equation method and considering the effect of dynamic water on pier and pile foundation with additional mass, the finite element numerical analysis model of Dongsha super large bridge is established by using the finite element software Midas. The dynamic characteristics of the case with or without the action of dynamic water are analyzed, The results show that the natural vibration frequency of the cable-stayed bridge is reduced by hydrodynamic action. The response spectrum and time history analysis of the longitudinal vertical and horizontal vertical conditions are carried out for the Dongsha super bridge with or without dynamic water action. The results show that the dynamic water has a great influence on the displacement of the key points and the internal force of the key section of the cable-stayed bridge. The traveling wave effect of Dongsha super large bridge is analyzed by using the large mass method. The influence of non-uniform excitation on the dynamic response of cable-stayed bridge is studied and compared with the calculated results under uniform excitation. The results show that the dynamic response of the structure decreases when the traveling wave effect is taken into account, and the response results tend to be consistent with the increase of the wave velocity. The seismic response of cable-stayed bridges is affected by the different water bodies with the apparent wave velocities of seismic waves under the action of traveling wave. The effect of water body on seismic response of cable-stayed bridge is different from that of traveling wave excitation. The viscous dampers are installed on Dongsha Bridge. The influence of damping coefficient C and velocity exponent 伪 of viscous dampers on the dynamic response of cable-stayed bridges is studied. It is found that selecting appropriate damper parameters can significantly reduce the bottom bending moment of the main tower of cable-stayed bridge and the displacement of the key points, and consider the bending moment of the main tower bottom synthetically. It is suggested that the damping coefficient of the damper should be set to 14000k N / s / m and the velocity exponent 0.35 for the influence of the displacement of the longitudinal bridge and the dynamic pressure of the bridge at the key points.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.27;U442.55
本文编号：2151481
[Abstract]:In recent years, with the continuous improvement of China's transportation network, there have been many deep-water bridges under construction and proposed. Under earthquake action, the motion of the substructure of deep water bridge will cause the radiation wave motion in the surrounding water body, and because of the relative motion between the structure and the water body, there will be dynamic water pressure on the substructure of the bridge. The hydrodynamic pressure has great influence on the dynamic characteristics and dynamic response of the structure itself. Therefore, it is of great significance for seismic design and safety assessment of deep water bridges to fully understand the influence of dynamic water pressure on the seismic dynamic response of cable-stayed bridges. The main contents and conclusions of this paper are as follows: 1. By using Morison equation method and considering the effect of dynamic water on pier and pile foundation with additional mass, the finite element numerical analysis model of Dongsha super large bridge is established by using the finite element software Midas. The dynamic characteristics of the case with or without the action of dynamic water are analyzed, The results show that the natural vibration frequency of the cable-stayed bridge is reduced by hydrodynamic action. The response spectrum and time history analysis of the longitudinal vertical and horizontal vertical conditions are carried out for the Dongsha super bridge with or without dynamic water action. The results show that the dynamic water has a great influence on the displacement of the key points and the internal force of the key section of the cable-stayed bridge. The traveling wave effect of Dongsha super large bridge is analyzed by using the large mass method. The influence of non-uniform excitation on the dynamic response of cable-stayed bridge is studied and compared with the calculated results under uniform excitation. The results show that the dynamic response of the structure decreases when the traveling wave effect is taken into account, and the response results tend to be consistent with the increase of the wave velocity. The seismic response of cable-stayed bridges is affected by the different water bodies with the apparent wave velocities of seismic waves under the action of traveling wave. The effect of water body on seismic response of cable-stayed bridge is different from that of traveling wave excitation. The viscous dampers are installed on Dongsha Bridge. The influence of damping coefficient C and velocity exponent 伪 of viscous dampers on the dynamic response of cable-stayed bridges is studied. It is found that selecting appropriate damper parameters can significantly reduce the bottom bending moment of the main tower of cable-stayed bridge and the displacement of the key points, and consider the bending moment of the main tower bottom synthetically. It is suggested that the damping coefficient of the damper should be set to 14000k N / s / m and the velocity exponent 0.35 for the influence of the displacement of the longitudinal bridge and the dynamic pressure of the bridge at the key points.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.27;U442.55
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