大跨度多塔斜拉桥主梁随机地震可靠性分析

发布时间：2018-01-14 03:11

本文关键词：大跨度多塔斜拉桥主梁随机地震可靠性分析　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：建成的大跨度多塔斜拉桥在交通系统中具有重要的地位,其具有长大的跨越规模和复杂的结构体系,因而对其进行科学合理的抗震设计和分析,是当前的一个重要课题。作为抗震理论的重要组成部分,地震可靠性分析理论已经取得了长足进步,但是对于大跨度多塔斜拉桥的随机地震可靠性分析方面还研究较少。论文以已建成的嘉绍跨江大桥作为研究对象,考虑地震激励和主梁结构参数两方面的随机性,建立其可靠性分析方法,从而得到主梁的随机地震可靠性指标,并进行评价分析。论文的主要内容为：1、系统梳理了结构随机地震可靠性分析方法,包括随机振动理论和多随机的可靠性分析方法两部分。前者包括地震动输入问题、地震动空间效应处理模型、随机地震响应功率谱方法,后者包括随机地震可靠性分析原理和结构可靠性分析理论两部分。2、通过建立嘉绍大桥的有限元模型,并分析其动力特性,了解其振型分布特征,并进一步对嘉绍大桥的刚度特性作出判断。选定主梁弹性模量、泊松比和质量来分析其对桥梁动力特性的影响程度,计算结果表明三者都是桥梁动力特性的敏感因素,其中弹性模量和主梁质量的影响更为敏感。3、采用随机振动方法求解嘉绍大桥在随机地震作用下的响应,比较了胡聿贤谱模型、欧进萍谱模型和杜修力谱模型下的响应影响,一维一致激励与三维一致激励下响应结果比较,以及考虑地震动的行波效应和相干效应对响应结果的影响。4、基于现行桥梁抗震设计规范和首次超越机制建立起相应的功能函数和极限状态,并采用响应面方法,在不同样本点处进行随机振动分析以求得响应结果,拟合出主梁结构的功能函数显式表达,最后用经典的矩方法分析其可靠性。结果表明主梁在随机地震荷载作用下,结构参数随机性对可靠性指标有较大的影响；嘉绍大桥主梁在随机地震荷载作用下,其可靠度指标满足规范规定的结构目标可靠度要求,结果说明嘉绍大桥主梁在设计地震作用下具有足够的安全性。
[Abstract]:Long span cable-stayed bridge built has an important position in the transportation system, which has grown across scale and complicated structure system, the seismic design and Analysis on the scientific and rational, is currently an important topic. As an important part of seismic theory, theory of seismic reliability analysis has been discussed great progress, but for the analysis of stochastic seismic reliability of long span cable-stayed bridge is less studied. Paper has built the Jiashao bridge as the research object, considering the randomness of two aspects of seismic excitation and girder structure parameters, establishes the reliability analysis method, so as to obtain the random seismic reliability index of main girder, and evaluation and analysis. The main contents of this paper are as follows: 1. Systematically analyzes the reliability analysis method of random seismic structure, including the theory of random vibration and random reliability The two part analysis method. The former includes seismic input, spatial effect model, response spectrum method of random earthquake, including random seismic reliability analysis of the two part is the theoretical principle and structure of.2 reliability, by establishing a finite element model of Jiashao bridge, and analyzes its dynamic characteristics, understand the vibration distribution the characteristics, judgment and further to Jiashao bridge stiffness. The selected beam elastic modulus influences the dynamic characteristics of bridge Poisson's ratio and quality, the calculation results show that the three are the sensitive factors of dynamic characteristics of the bridge, the influence of the elastic modulus and the beam quality is more sensitive to the.3 response the random vibration method of Jiashao bridge under random excitation, the Hu spectral model model, Ou Jinping spectrum model and spectrum response Du Xiuli shadow model under a one-dimensional ring Induced and 3D under uniform excitation and traveling wave effect response results, considering seismic and coherent effects on the response of the.4, the current seismic design codes and standards and establish a mechanism for the first time beyond the function and limit state based on the corresponding, and using the response surface method for random vibration analysis in different sample points to to obtain results, fitting function of main girder structure explicit expression, finally using moment method classical reliability analysis. The results show that in the main girder under random seismic loading, the randomness of the structural parameter has great influence on reliability index; Jiashao bridge girders under random seismic loading, the reliability indexes meet the requirements the degree of structure of the target specification is reliable, the main girder of Jiashao bridge has enough safety in the design earthquake.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55;U448.27

【参考文献】