结构抗连续倒塌关键构件的评价方法及敏感性分析

发布时间：2018-10-10 14:12

【摘要】：建筑物的连续倒塌是一种危害性很强的工程灾害,往往带来严重的人员伤亡和巨大的经济损失,是近年来土木工程界研究的热点问题之一。确定结构在连续倒塌中的关键构件,以及连续倒塌对各个设计参数的敏感性程度,对于结构的抗连续倒塌设计具有十分重要的意义。当确定了结构的关键构件和敏感设计参数之后,可以有重点、有目标地对结构进行加固设计,最大限度地减少连续倒塌的发生。然而,截至目前,世界各国的设计规范都未能提出具体的关键构件确定方法。本文分别从钢梁悬链线屈服理论以及能量法入手,推导了确定结构关键构件的相关计算公式；利用ABAQUS有限元软件及相应的计算模型,对框架结构连续倒塌关于设计参数的敏感性进行了探索性研究。具体工作可分为以下几个部分： 1.通过对钢梁在悬链线作用阶段的受力状态的分析,推导了钢梁在悬链线阶段最大容许位移的计算公式,进而引出了柱的“特征移除系数(μ)”的概念,定量地计算了构件在连续倒塌中的重要性指标。利用ABAQUS有限元软件对一实际工程进行了非线性动力分析,结果表明,特征移除位移的算法能够在一定程度上反映出构件在抗连续倒塌中的重要性程度,预测结果与一般工程经验一致。且适合结构化编程计算。 2.在结构的抗连续倒塌设计中,能量法是一个很好的切入点。作为构件的重要性评价指标,以拆除构件前后,结构体系的变形能的变化率作为衡量构件重要性程度的指标,形象直观。在此基础上,引入Neumann级数进行重要性系数的简化计算,避免了反复求解构件破坏后的整体刚度矩阵的过程,提高了计算效率,且具有较高的精度。另外,进一步地提出了“扩展的重要性系数”的概念,可以用来进行多构件同时破坏情况下的结构危险性的比较分析。 3.利用ABAQUS有限元软件建立了一组设计参数(层数,抗震烈度,配箍率等)不同的钢筋混凝土框架模型,通过拆除构件法计算结构发生连续倒塌的严重性程度,并进行比较分析。结果表明,结构连续倒塌对于楼层数和配箍率的敏感性程度较高,对于建筑物抗震设防烈度的敏感性程度较低。
[Abstract]:The continuous collapse of buildings is a very harmful engineering disaster, which often brings serious casualties and huge economic losses. It is one of the hot issues in the field of civil engineering in recent years. It is very important for the continuous collapse design to determine the key members of the structure in the continuous collapse and the sensitivity of the continuous collapse to the various design parameters. When the key components and sensitive design parameters of the structure are determined, it is possible to design the structure with emphasis and aim, so as to minimize the occurrence of continuous collapse. However, up to now, the design specifications in the world have failed to propose specific methods for determining key components. Starting with the catenary yield theory and energy method of steel beam, this paper deduces the relevant calculation formulas for determining the key components of the structure, and makes use of the ABAQUS finite element software and the corresponding calculation model. The sensitivity of continuous collapse of frame structures to design parameters is studied in this paper. Specific work can be divided into the following parts: 1. Based on the analysis of the stress state of the steel beam in the catenary action stage, the formula for calculating the maximum allowable displacement of the steel beam in the catenary stage is derived, and the concept of "characteristic removal coefficient (渭)" of the column is introduced. The importance index of component in continuous collapse is calculated quantitatively. The nonlinear dynamic analysis of a practical project is carried out by using ABAQUS finite element software. The results show that the displacement removal algorithm can reflect to some extent the importance of the component in the continuous collapse resistance. The prediction results are consistent with the general engineering experience. And suitable for structured programming calculation. 2. Energy method is a good breakthrough point in continuous collapse design. As the importance evaluation index of the component, the change rate of the deformation energy of the structure system before and after the removal of the component is taken as the index to measure the importance degree of the component, and the image is intuitionistic. On this basis, the Neumann series is introduced to simplify the calculation of the importance coefficient, which avoids the process of repeatedly solving the whole stiffness matrix after the member is destroyed, and improves the calculation efficiency and has a higher accuracy. In addition, the concept of "extended importance coefficient" is further put forward, which can be used to compare and analyze the structural hazards in the case of simultaneous failure of multiple components. A set of reinforced concrete frame models with different design parameters (floor number, seismic intensity, hoop ratio, etc.) are established by using ABAQUS finite element software. The severity of continuous collapse of structures is calculated by the method of removing the members, and the degree of continuous collapse is compared and analyzed. The results show that the continuous collapse of the structure is highly sensitive to the number of floors and hoop ratio, and less sensitive to the seismic fortification intensity of buildings.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU311.4

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