桥梁强健性理论及关键构件研究

发布时间：2018-03-14 13:40

本文选题：桥梁　切入点：强健性　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：现代桥梁结构所处的环境日益复杂,在运营阶段部分构件的损伤与破坏不可完全避免,因此确定桥梁结构各构件的重要性系数,研究在某构件失效时桥梁结构是否具有良好的抗连续倒塌能力显得尤为重要。但是目前对于桥梁连续倒塌的研究相对匮乏。论文从各类桥梁结构入手,将桥梁结构分为四类连续倒塌模式,并以能量法计算桥梁结构各构件的重要性系数,分析桥梁结构在出现构件失效时的强健性。论文主要的研究工作和结论如下：1.归纳总结建筑结构强健性研究成果的基础上,指出现行的桥梁规范在连续倒塌设计方面研究的不足,而桥梁结构在运营阶段遇到的偶然荷载具有很强的不确定性,部分构件的损伤和失效不可避免,因此提出桥梁结构需要研究因特殊事件导致构件失效的情况下桥梁结构的强健性。2.根据桥梁结构发生连续倒塌的状态将桥梁结构连续倒塌分为四类连续倒塌模式,利用能量法计算桥梁各构件的重要性系数,并结合定性分析对桥梁结构构件分类,确定各倒塌类型桥梁结构中的关键构件；利用ANSYS的瞬态分析功能,以构件瞬时拆除法模拟构件突然失效,分别对多类桥梁构件失效进行静力、动力分析。3.分析表明,桥梁结构中重要性系数大的构件失效时对剩余结构的动力影响显著,某些构件失效会导致桥梁结构在极短的时间内发生连续性破坏。讨论桥梁结构中构件的安全储备量并确定其合理取值。对于“多米诺型”连续倒塌桥梁以自锚式悬索桥为算例,分析表明吊索突然断裂对紧邻的吊索影响剧烈,为避免单根吊索突然断裂引起吊索连续断裂,吊索安全储备应超过2.5;为避免相邻两根吊索同时断裂引起吊索连续断裂,吊索的安全系数应调整为原设计的1.4倍,即将安全系数取为4.2；对于“失稳型”连续倒塌桥梁以某造型独特的斜拉桥为算例,分析表明,该桥的圆拱形桥塔处设置的对拉索失效将导致桥梁结构连续倒塌,为避免这一情况的出现,桥塔的刚度应增大到原设计值的1.7倍,使桥梁结构具有良好的强健性；对于“外部约束”连续失效型桥梁以连续梁桥为算例,分析表明,梁端处重载侧的竖向约束失效会导致剩余约束连续失效,为避免这一情况,连续梁中间墩处应增设抗扭约束。
[Abstract]:The environment of modern bridge structure is becoming more and more complex, and the damage and damage of some components can not be completely avoided in the operation stage. Therefore, the importance coefficient of each component of bridge structure is determined. It is very important to study whether the bridge structure has good ability to resist continuous collapse when a member fails. However, the research on continuous collapse of bridge is relatively scarce. The bridge structure is divided into four types of continuous collapse modes, and the importance coefficient of each component of the bridge structure is calculated by energy method. The main research work and conclusions of this paper are as follows: 1. On the basis of summarizing the research results of building structure robustness, It is pointed out that the existing bridge codes are insufficient in the research of continuous collapse design, and the accidental loads encountered in the operation stage of bridge structures are very uncertain, so the damage and failure of some members are inevitable. Therefore, it is necessary to study the robustness of bridge structure under the condition of structural failure caused by special events. 2. According to the state of continuous collapse of bridge structure, the continuous collapse of bridge structure can be divided into four types of continuous collapse modes. Using the energy method to calculate the importance coefficient of each component of the bridge, and combining qualitative analysis to classify the components of the bridge structure, to determine the key components of each collapse type bridge structure, to use the transient analysis function of ANSYS, In this paper, the transient demolition method is used to simulate the sudden failure of the member, and the static analysis of the failure of many kinds of bridge members is carried out respectively. 3. The analysis shows that the dynamic effect on the residual structure is significant when the member with the large importance coefficient of the bridge structure fails. The failure of some components will lead to the continuous damage of bridge structure in a very short time. The safety reserve of the components in the bridge structure is discussed and the reasonable value is determined. The self-anchored suspension bridge is taken as an example for a "domino" continuous collapse bridge. The analysis shows that the sudden fracture of the sling has a severe effect on the adjacent slings. In order to avoid the continuous fracture of the sling caused by the sudden fracture of the single sling, the safety reserve of the sling should exceed 2.5, and to avoid the continuous fracture of the sling caused by the simultaneous fracture of the adjacent two sling lines, The safety factor of the sling should be adjusted to 1.4 times of the original design, that is to say, the safety factor should be taken as 4.2. For the continuous collapse of the "unstable" bridge, a special cable-stayed bridge of unique shape is taken as an example. The failure of cable at the circular arch tower of the bridge will lead to the continuous collapse of the bridge structure. In order to avoid this situation, the stiffness of the tower should be increased to 1.7 times of the original design value, so that the bridge structure has good robustness. For the continuous failure bridge with "external constraint" as an example, the analysis shows that the vertical constraint failure of the overloaded side at the end of the beam will lead to the continuous failure of the residual constraint. In order to avoid this situation, the torsional constraint should be added at the middle pier of the continuous beam.
【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】：U441

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