大跨径刚构—连续组合梁桥的行波效应理论及地震易损性分析
发布时间：2018-09-12 20:03
【摘要】：桥梁作为交通建设中较为重要的工程建筑结构,其安全性、适用性和耐久性越来越受到人们的重视。近几十年来,我国桥梁建设的不断发展,随着交通发展的要求,大跨径连续梁桥在桥梁工程中也得到了更加广泛的应用,而且大型桥梁的经济性和安全性对国家和人民来说都有着更为重大的影响。本文对大跨径刚构-连续组合梁桥的行波效应进行了研究,在假定桥墩基础处地震波幅值及频谱特性不变的前提下,建立该桥动力分析模型。采用动态时程分析方法研究了纵桥向行波效应对桥梁的墩底弯矩以及支座位移的地震响应变化。结果表明：(1)行波效应作用下,支座位移的地震响应与一致输入相比较存在放大效应,工程建设中应当充分考虑行波效应带来的不利影响,支座离墩梁固结处越远,放大效应越明显,因而在设计这一类桥梁时应考虑足够的支座位移预留；(2)行波效应作用下,桥墩墩底弯矩存在放大效应,桥墩位置的不同,弯矩增大效应存在差异,且行波效应产生的墩底弯矩具有明显的方向性,沿地震波传播方向,墩底弯矩逐渐减小。(3)行波效应对大跨径刚构-连续组合梁桥的影响主要集中在设置支座的桥墩及其对应支座上,而且呈现出地震波传播速度越小,影响越大的趋势；而对于墩梁固结的双柱式矩形实心墩的影响则较小。本文还针对大跨度刚构-连续组合梁桥的关键位置进行了地震易损性数值分析,并绘制出其理论地震易损性曲线。首先通过对已有桥梁震害的分析,得出了大跨度刚构-连续组合梁桥的易损部位主要是桥墩和支座,并对该桥的某一个主墩施加20条地震波,确定了桥墩易损的关键位置是墩顶和墩底。对比分析了作为地面运动的强度指标,采用PGA计算结果的离散性要比采用SA时大得多,因此采用SA作为地面运动强度指标得出的结果更为准确。本文采用非线性的最小二乘法分别绘制了在纵桥向和横桥向地震波作用下的桥墩和支座的地震易损性曲线,通过对每个桥墩墩顶和墩底易损性曲线之间的相互比较及对不同桥墩相同部位易损性曲线的比对发现,墩底比墩顶容易受损；横向地震波作用下的桥墩和支座比纵桥向地震波作用下的更容易受损。
[Abstract]:As an important engineering structure in traffic construction, more and more attention has been paid to the safety, applicability and durability of bridges. In recent decades, with the continuous development of bridge construction in China, with the development of traffic, long-span continuous beam bridge has been more widely used in bridge engineering. And the economy and safety of large bridges have a more significant impact on the country and people. In this paper, the traveling wave effect of long-span rigid-frame-continuous composite beam bridge is studied, and the dynamic analysis model of the bridge is established on the assumption that the amplitude and spectrum of seismic wave at the pier foundation are invariant. The dynamic time-history analysis method is used to study the seismic response of longitudinal bridge traveling wave effect to the bending moment at the pier bottom and the displacement of the support of the bridge. The results show that: (1) under the action of traveling wave effect, the seismic response of support displacement has amplification effect compared with uniform input, and the adverse effect caused by traveling wave effect should be fully considered in engineering construction, and the farther the support is from the consolidation of pier and beam, The more obvious the amplification effect is, the more sufficient support displacement reservation should be considered in the design of this kind of bridge. (2) under the action of traveling wave effect, there exists amplification effect on the bending moment at the bottom of the pier, and the effect of increasing moment on the bridge pier is different with the location of the pier. The bending moment at the bottom of the pier caused by traveling wave effect has obvious directionality and propagates along the direction of seismic wave. (3) the effect of traveling wave effect on long-span rigid-frame-continuous composite beam bridge is mainly concentrated on the pier with bearing and its corresponding support, and the smaller the velocity of seismic wave propagation, the greater the influence; However, the effect of double column rectangular solid pier on the consolidation of pier beam is small. In this paper, the seismic vulnerability of long-span rigid-frame-continuous composite beam bridge is numerically analyzed and the theoretical seismic vulnerability curve is drawn. By analyzing the earthquake damage of existing bridges, it is concluded that the main vulnerable parts of long-span rigid-frame-continuous composite beam bridges are piers and supports, and 20 seismic waves are applied to one of the main piers of the bridge. It is determined that the key position of pier vulnerability is pier top and pier bottom. As the strength index of the ground motion, the dispersion of the calculated results with PGA is much greater than that with SA, so the results obtained by using SA as the index of the intensity of ground motion are more accurate. In this paper, the nonlinear least square method is used to draw the seismic vulnerability curves of piers and supports under the action of longitudinal and transverse bridge seismic waves, respectively. By comparing the vulnerability curves between the top of each pier and the bottom of the pier, and comparing the vulnerability curves of the same part of different piers, it is found that the pier bottom is easier to be damaged than the top of the pier. The bridge piers and supports under transverse seismic waves are more easily damaged than those under longitudinal seismic waves.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55
本文编号：2240084
[Abstract]:As an important engineering structure in traffic construction, more and more attention has been paid to the safety, applicability and durability of bridges. In recent decades, with the continuous development of bridge construction in China, with the development of traffic, long-span continuous beam bridge has been more widely used in bridge engineering. And the economy and safety of large bridges have a more significant impact on the country and people. In this paper, the traveling wave effect of long-span rigid-frame-continuous composite beam bridge is studied, and the dynamic analysis model of the bridge is established on the assumption that the amplitude and spectrum of seismic wave at the pier foundation are invariant. The dynamic time-history analysis method is used to study the seismic response of longitudinal bridge traveling wave effect to the bending moment at the pier bottom and the displacement of the support of the bridge. The results show that: (1) under the action of traveling wave effect, the seismic response of support displacement has amplification effect compared with uniform input, and the adverse effect caused by traveling wave effect should be fully considered in engineering construction, and the farther the support is from the consolidation of pier and beam, The more obvious the amplification effect is, the more sufficient support displacement reservation should be considered in the design of this kind of bridge. (2) under the action of traveling wave effect, there exists amplification effect on the bending moment at the bottom of the pier, and the effect of increasing moment on the bridge pier is different with the location of the pier. The bending moment at the bottom of the pier caused by traveling wave effect has obvious directionality and propagates along the direction of seismic wave. (3) the effect of traveling wave effect on long-span rigid-frame-continuous composite beam bridge is mainly concentrated on the pier with bearing and its corresponding support, and the smaller the velocity of seismic wave propagation, the greater the influence; However, the effect of double column rectangular solid pier on the consolidation of pier beam is small. In this paper, the seismic vulnerability of long-span rigid-frame-continuous composite beam bridge is numerically analyzed and the theoretical seismic vulnerability curve is drawn. By analyzing the earthquake damage of existing bridges, it is concluded that the main vulnerable parts of long-span rigid-frame-continuous composite beam bridges are piers and supports, and 20 seismic waves are applied to one of the main piers of the bridge. It is determined that the key position of pier vulnerability is pier top and pier bottom. As the strength index of the ground motion, the dispersion of the calculated results with PGA is much greater than that with SA, so the results obtained by using SA as the index of the intensity of ground motion are more accurate. In this paper, the nonlinear least square method is used to draw the seismic vulnerability curves of piers and supports under the action of longitudinal and transverse bridge seismic waves, respectively. By comparing the vulnerability curves between the top of each pier and the bottom of the pier, and comparing the vulnerability curves of the same part of different piers, it is found that the pier bottom is easier to be damaged than the top of the pier. The bridge piers and supports under transverse seismic waves are more easily damaged than those under longitudinal seismic waves.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U442.55
【参考文献】
相关期刊论文 前2条
1 何庆祥;沈祖炎;;结构地震行波效应分析综述[J];地震工程与工程振动;2009年01期
2 彭天波;李建中;范立础;;能力设计方法在双层高架桥梁抗震设计中的应用[J];世界桥梁;2009年01期
，本文编号：2240084
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