大跨度连续刚构桥施工阶段地震响应分析

发布时间：2018-03-17 19:36

本文选题：连续刚构桥　切入点：施工阶段　出处：《长沙理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：近年来我国西南地区的地震活动较为频繁,连续刚构桥在施工阶段的地震响应对桥梁成桥后全桥的地震响应有着很大的影响,而在现有的施工工艺条件下,大跨度桥梁施工周期一般比较长,导致大跨度桥梁在施工中遇到地震的几率增大,因此在施工过程中对大跨度桥梁的地震响应分析很有必要,另外,近年来从地震对桥梁的破坏形式可以看出,由于桥梁施工过程中对桩—土效应考虑不足,导致在地震发生时,桥梁破坏普遍比较严重,现阶段国内外对大跨径连续刚构桥在施工阶段的桩—土效应对桥梁的抗震响应分析研究较少,本文以四川赤水河大桥为例,采用反应谱分析法和动态时程分析法对施工阶段中最不利工况的地震响应进行了对比分析。本文主要内容如下：(1)根据地震响应分析理论的发展,对地震响应分析理论进行了总结,通过横向对比的方式,指出各个地震响应分析理论的优点与不足,并对各个方法的适应范围进行了大概的描述,讨论了影响施工阶段地震响应的主要几个影响因素,为下文做准备。(2)详细的介绍了大跨度连续刚构桥的动力学特点及动力学特性的分析方法,结合这些动力学特性,利用MIDAS有限元软件以四川赤水河大桥实例,分别建立了考虑桩-土效应和不考虑桩-土效应的两种有限元对比模型,并得到了在各个施工阶段与全桥建成后的自振结果与动力特性。(3)利用反应谱分析法对大跨度连续刚构桥的施工阶段地震发生时的几个不利阶段进行地震响应分析,通过对两种不同模型的计算结果可知,桥梁在考虑桩—土效应时,随着施工的进行,悬臂端各个方向上的位移幅值增大,根据不同地震激励输入方向的不同,墩底弯矩和剪力程增大趋势。(4)利用动力时程分析方法在对施工过程中相同的施工阶段进行地震时程响应分析,在考虑结构阻尼和桩-土效应影响的情况下,对桥梁的两种对比模型进行计算分析,由其分析结果可知,在单一的地震激励作用下,悬臂端各个响应变化趋势和反应谱分析所得到的的结论大致相同,而在组合地震激励下,墩底的弯矩和剪力响应变化不一,但此时结构各个响应都达到了最大值,结构处于抗震不利阶段。
[Abstract]:The seismic response of continuous rigid frame bridge in the construction stage has a great influence on the seismic response of the whole bridge after the bridge is completed in recent years, but under the existing construction conditions, the seismic response of the bridge in southwest China is relatively frequent. The construction period of long-span bridges is generally long, which leads to the increase of the probability of earthquake encountered in the construction of long-span bridges. Therefore, it is necessary to analyze the seismic response of long-span bridges during construction. In recent years, it can be seen from the damage form of earthquake to bridge, because of the insufficient consideration of pile-soil effect in bridge construction, the bridge damage is generally serious when the earthquake occurs. At present, there is little research on the seismic response of long-span continuous rigid frame bridge under pile-soil effect in the construction stage at home and abroad. This paper takes Chishui River Bridge in Sichuan as an example. Response spectrum analysis and dynamic time history analysis are used to compare and analyze the seismic response of the most unfavorable working conditions in the construction stage. The main contents of this paper are as follows: 1) according to the development of the theory of seismic response analysis, This paper summarizes the theory of seismic response analysis, points out the advantages and disadvantages of each theory of seismic response analysis by means of horizontal comparison, and gives a general description of the applicability of each method. This paper discusses the main factors that affect the seismic response in the construction stage, and introduces in detail the dynamic characteristics of the long-span continuous rigid frame bridge and the analysis method of the dynamic characteristics, combining with these dynamic characteristics. By using the MIDAS finite element software, two finite element comparison models are established for considering pile-soil effect and not considering pile-soil effect respectively with the example of Chishui River Bridge in Sichuan Province. The natural vibration results and dynamic characteristics of each construction stage and the whole bridge are obtained. The response spectrum analysis method is used to analyze the seismic response of several unfavorable phases in the construction stage of the long-span continuous rigid frame bridge. Through the calculation results of two different models, it can be seen that with the construction of the bridge considering pile-soil effect, the amplitude of displacement in each direction of the cantilever end increases, according to the different input direction of different earthquake excitation. The dynamic time-history analysis method is used to analyze the seismic time-history response of the same construction stage in the construction process, considering the influence of structural damping and pile-soil effect. The two comparative models of the bridge are calculated and analyzed. The results show that under the action of single earthquake excitation, the variation trend of each response and the response spectrum analysis of the cantilever end are approximately the same, but under the combined earthquake excitation, the results are similar. The bending moment and shear response at the bottom of the pier vary greatly, but each response of the structure reaches the maximum at this time, and the structure is in the unfavorable stage of earthquake resistance.
【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;U448.23

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