基于可靠度理论的钢筋混凝土梁式桥地震安全性研究

发布时间：2018-05-06 23:33

本文选题：可靠度理论 + 地震安全性　；参考：《中国地震局工程力学研究所》2017年硕士论文

【摘要】：我国广大城市经济和城镇化处于高速发展阶段,当面临地震灾害时,要求城市工程系统具有足够的地震安全性。作为生命线工程系统的重要组成部分,城市桥梁的地震安全性一直备受关注。如果桥梁在地震中受到了严重破坏,会引起交通的中断甚至瘫痪,导致无法进行正常的物资运输和人员伤亡的救援工作。而桥梁在使用期内,当经历了自然老化、车辆荷载、外界环境等影响,其地震安全性水平尚不明确。所以有必要对桥梁的地震安全性进行分析和评价。以往的研究大都没有直接给出桥梁地震安全性的定义以及评价其安全性的直接指标,对已建桥梁的地震安全性,也没有同时考虑地震作用和结构参数的随机性,故本文分析了现有研究成果和方法的优缺点,以这些研究成果为基础,提出了桥梁地震安全性的概念,从桥梁可靠度理论出发,研究了钢筋混凝土梁式桥的地震安全性,并建立了一个钢筋混凝土梁桥的地震安全性评价体系框架。主要包括以下内容:1.本文基于可靠度理论,考虑了对结构抗力有重要影响的材料强度随机性和计算模式的不确定性,在研究了构件的震害现象和破坏准则后,给出了构件不同损伤极限状态下的功能函数。用响应面法计算桥墩、支座和基础在多遇地震、常遇地震、罕遇地震下的失效概率,得到了构件在设计基准期内两阶段设计条件下的地震可靠度。2.定义了地震安全评价指标,给出了构件不同安全等级的划分标准,判断了构件不同损伤状态的安全性和使用情况。定义了桥梁系统中单元的概念以及桥梁单元的地震安全等级划分,最后建立了钢筋混凝土桥梁系统的地震安全性评价方法,以此评价已建桥梁的地震安全性。3.给出了钢筋混凝土连续梁桥的工程算例。以钢筋和混凝土强度为输入变量,按照计算构件失效概率、地震可靠度的步骤,计算了桥墩、支座、基础的失效概率和可靠度,并按照定义的安全指标,计算了构件的安全等级以及钢筋混凝土梁桥体系的安全等级,以此评价已建桥梁系统的地震安全性。
[Abstract]:The urban economy and urbanization in China are in the stage of rapid development. When faced with earthquake disaster, the urban engineering system is required to have sufficient seismic safety. As an important part of lifeline engineering system, the seismic safety of urban bridges has been paid more and more attention. If the bridge is seriously damaged in the earthquake, traffic will be interrupted or even paralyzed, which will lead to the failure to carry out normal material transportation and rescue work of casualties. However, the seismic safety level of the bridge is not clear when it is affected by natural aging, vehicle load, external environment and so on. So it is necessary to analyze and evaluate the seismic safety of bridges. Most previous studies have not directly given the definition of bridge seismic safety and the direct index to evaluate its safety. The seismic safety of existing bridges is not considered at the same time as the randomness of seismic action and structural parameters. In this paper, the advantages and disadvantages of existing research results and methods are analyzed. Based on these research results, the concept of bridge seismic safety is put forward. Based on the theory of bridge reliability, the seismic safety of reinforced concrete beam bridges is studied. A framework for seismic safety evaluation of reinforced concrete beam bridges is established. Mainly include the following content: 1. Based on the reliability theory, this paper considers the randomness of material strength and the uncertainty of calculation model, which have an important influence on the structural resistance. The function functions under different damage limit states are given. The response surface method is used to calculate the failure probability of bridge piers, supports and foundations under the conditions of frequent, frequent and rare earthquakes, and the seismic reliability of components under the condition of two-stage design in the design reference period is obtained. The evaluation index of seismic safety is defined, and the criteria of different safety grades are given, and the safety and application of different damage states of components are judged. The concept of the element in the bridge system and the classification of the seismic safety grade of the bridge element are defined. Finally, the seismic safety evaluation method of the reinforced concrete bridge system is established to evaluate the seismic safety of the existing bridge. An engineering example of reinforced concrete continuous beam bridge is given. Taking the strength of reinforcement and concrete as input variables, the failure probability and reliability of pier, bearing and foundation are calculated according to the steps of calculating the failure probability and seismic reliability of the member, and according to the defined safety index, the failure probability and reliability of bridge pier, bearing and foundation are calculated. The safety grade of the components and the safety grade of the reinforced concrete beam bridge system are calculated to evaluate the seismic safety of the existing bridge system.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55

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