钢箱梁斜拉桥抗震能力评估方法研究

发布时间：2018-04-22 09:35

本文选题：钢箱梁 + 斜拉桥　；参考：《广西大学》2014年硕士论文

【摘要】：钢箱梁斜拉桥是现代大跨径斜拉桥的发展趋势。因此,开展钢箱梁斜拉桥进行抗震能力评估方法及其震害评价研究,对该类桥梁抗震设计和灾后的结构破坏评估与加固具有重要意义。本文基于结构屈服强度与延性的抗震评估理念,根据不同构件单元破坏模式进行小震反应下的破坏强度及其延性的计算。围绕结构抗震能力的计算和地震损伤破坏下的震害评价,进行钢箱梁斜拉桥的抗震能力评估,提出了钢箱梁斜拉桥抗震能力评估方法。论文的主要内容如下： 1.结构构件的屈服强度计算主要按照现行规范计算,结构的延性计算依据其力学性能指标进行求解。在计算中,对钢筋混凝土箱形截面强度计算公式和钢箱梁、群桩基础及支座的延性计算公式进行了合理推导。在结构延性求解中,钢箱梁部件以纯弯作用下的极限弯矩与屈服弯矩之比求取其延性比,基础部件以最不利单桩的延性作为基础整体的延性、支座部件以橡胶剪切变形的极限位移与屈服位移之比计算其延性比。 2.钢箱梁斜拉桥抗震能力评估方法原理是：首先采用有限元软件计算结构构件单元在短期效应组合S和小震作用(0.05g)下的内力继而求解破坏加速度系数α,然后根据构件的延性能力计算容许延性容量Ra,再依据结构的自振周期、场地类型确定结构系统地震力折减系数F。最后,由破坏加速度系数α、地震力折减系数Fu和小震作用下的地面运动加速度ag得到各构件的抵抗地面运动的最大加速度A。加权计算各部件的A,综合各部件最小的A作为钢箱梁斜拉桥整桥的抗震能力。 3.采用变权综合层次分析法(AHP)计算钢箱梁斜拉桥各部件的权重及整桥地震损伤破坏指数。参照抗震结构的破坏准则及本文桥梁抗震能力评估方法的特点,提出了钢箱梁斜拉桥的破坏模型,并依据《中国地震烈度表》(GB/T17742-2008)提出了钢箱梁斜拉桥震害的评价标准。由结构抗震能力和震害的评估结果可有效找到结构的抗震薄弱处及其破坏程度。 4.对某钢箱梁斜拉桥进行抗震能力评估,评估结果表明：该评估方法简单可行,能定量评估桥梁的抗震能力,定性分析桥梁的震害情况。
[Abstract]:Steel box girder cable-stayed bridge is the development trend of modern long span cable-stayed bridge. Therefore, it is of great significance for the seismic design, structural damage assessment and reinforcement of steel box girder cable-stayed bridges to carry out seismic capacity assessment and seismic damage evaluation. Based on the aseismic evaluation concept of yield strength and ductility of structures, the failure strength and ductility of structures under small earthquake response are calculated according to the failure modes of different member elements. The aseismic capacity of steel box girder cable-stayed bridge is evaluated according to the calculation of seismic capacity and the evaluation of seismic damage under earthquake damage, and the evaluation method of seismic capacity of steel box girder cable-stayed bridge is put forward. The main contents of the thesis are as follows: 1. The yield strength of structural members is mainly calculated according to the current code, and the ductility calculation is based on its mechanical properties. In the course of calculation, the formulas for calculating the strength of reinforced concrete box section and the ductility of steel box girder, pile group foundation and support are deduced reasonably. In the calculation of ductility, the ductility ratio of steel box girder components is calculated by the ratio of ultimate moment to yield moment under pure bending, and the ductility of foundation component is based on the most unfavorable ductility of single pile. The ductility ratio of bearing parts is calculated by the ratio of ultimate displacement to yield displacement of rubber shear deformation. 2. The evaluation principle of seismic capacity of cable-stayed bridge with steel box girder is as follows: firstly, the internal force of structural member element under the combination of short-term effect S and small earthquake is calculated by finite element software, then the failure acceleration coefficient 伪 is solved according to the structure. The ductility capacity of the component is calculated by the allowable ductility capacity Ra. and then according to the natural vibration period of the structure, The seismic force reduction coefficient of structural system is determined by site type. Finally, from the failure acceleration coefficient 伪, the seismic force reduction factor Fu and the ground motion acceleration ag under the action of small earthquakes, the maximum acceleration A of each component to resist the ground motion is obtained. The A of each component is calculated weighted, and the minimum A of each component is taken as the seismic capacity of the whole bridge of steel box girder cable-stayed bridge. 3. The weight of the components of the cable-stayed bridge with steel box girder and the damage index of the whole bridge are calculated by using the variable weight comprehensive analytic hierarchy process (AHP). According to the failure criterion of seismic structure and the characteristics of the evaluation method of seismic capacity of this paper, the failure model of cable-stayed bridge with steel box girder is put forward, and the evaluation standard of earthquake damage of cable-stayed bridge with steel box girder is put forward according to "China Seismic intensity Table" (GBR / T17742-2008). The seismic weakness and damage degree of the structure can be effectively found from the evaluation results of the seismic capacity and damage of the structure. 4. The seismic capacity of a steel box girder cable-stayed bridge is evaluated. The results show that the evaluation method is simple and feasible. It can quantitatively evaluate the seismic capacity of the bridge and qualitatively analyze the earthquake damage of the bridge.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.27;U442.55

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