火灾高温作用下钢框架结构倒塌行为研究

发布时间：2018-03-10 12:56

本文选题：高温　切入点：钢框架　出处：《哈尔滨工程大学》2014年博士论文　论文类型：学位论文

【摘要】：随着“9.11”事件中世贸双塔的倒塌,在世界范围内引发了对火灾作用下结构连续性倒塌问题的广泛关注。由于钢结构相对混凝土结构更易在火灾高温作用下发生破坏,且破坏一旦发生后果就比较严重,所以钢结构在火灾作用下的倒塌破坏和失效分析更是成为研究的重点。为了最大限度的降低火灾对钢结构带来的危害,减少钢结构倒塌和失效带来的人员和财产损失,研究人员必须首先对钢结构的受火失效过程充分了解,并能准确评估出结构在火灾作用下是否会发生失效破坏以及破坏达到的程度。目前,由于对整体结构进行火灾试验耗资巨大,且会造成资源的大量浪费,所以试验研究多集中在单独的构件方面,包括梁、柱、板以及剪力墙等。这就使得通过理论分析以及数值模拟的方式对整体结构进行火灾作用下的失效过程分析显得尤为重要。本论文针对钢框架结构在火灾高温作用下的结构响应展开了一系列的理论分析和数值模拟,研究主要包括以下几方面的内容:(1)对现有文献中给出的结构连续倒塌设计方法(包括拉结力法和改变路径法)进行归纳。给出拉结力法荷载和抗力系数、楼板荷载以及拉结强度的确定方法;改变路径法关键构件的选取原则、荷载的组合形式、结构的破坏限度以及验收标准。同时,对国内外在高温下钢材的热和力学性能方面取得的研究成果进行了汇总;(2)基于连续性理论,采用转换矩阵法,推导出钢框架-剪力墙结构随温度的升高其内力和变形的计算公式,并通过MATLAB编程予以实现。通过对一榀四层四跨的钢框架-混凝土剪力墙结构进行受火分析,将推导公式的计算结果和有限元的分析结果进行比较,互为验证;(3)基于APM,通过时间历史分析函数在结构中引入初始破坏,在给出构件受损伤失效后结构动力响应的同时,对结构在火灾次生灾害作用下的失效全过程进行了分析,并给出受损伤结构在火灾高温作用下的破坏形式以及安全逃生时间;(4)通过对受损伤结构和完整结构在火灾高温作用下的失效过程进行对比分析,研究初始破坏对结构火灾高温行为的影响。通过比较不同火灾环境以及火灾位置下的结构响应,研究初始升温速率和边跨、中间跨受火对结构抗火性能的影响;(5)给出钢框架结构在火灾高温作用下,从升温初始时刻到受火构件失效整个过程中结构内力和变形的计算方法,并讨论了构件正常工作应力水平对其受火失效温度的影响。同时基于DCR准则,给出在役钢框架结构在火灾高温作用下的抗连续倒塌评估方法。通过算例对评估的具体方法进行了说明,并讨论了梁跨度的改变对受火钢框架结构内力和失效形式的影响。
[Abstract]:With the collapse of the twin towers in the "9 / 11" incident, widespread attention has been paid to the continuous collapse of the structure under fire worldwide. Because steel structures are more vulnerable to damage under fire and high temperature than concrete structures, In order to minimize the damage caused by fire, the collapse failure and failure analysis of steel structure under fire is the focus of the research. To reduce the loss of personnel and property caused by collapse and failure of steel structures, researchers must first fully understand the process of fire failure of steel structures. And it can accurately evaluate whether the structure will fail and damage and the degree of damage under the fire. At present, because of the large cost of fire test on the whole structure, and will cause a large amount of waste of resources, So most of the experimental studies are focused on individual components, including beams and columns. This makes it very important to analyze the failure process of the whole structure under fire by theoretical analysis and numerical simulation. A series of theoretical analysis and numerical simulation are carried out. The research mainly includes the following contents: 1) summarizing the design methods of continuous collapse of structures (including the method of tension force and the method of changing path), and giving the load and resistance coefficient of the method of tension force. The method of determining floor load and tensile strength; changing the selection principle of key components of the path method, the form of combination of loads, the damage limit of structure and the acceptance criteria, at the same time, Based on the theory of continuity, the transformation matrix method is used to summarize the research results on the thermal and mechanical properties of steel at high temperature at home and abroad. The formulas of internal force and deformation of steel frame-shear wall structure with increasing temperature are derived and realized by MATLAB programming. A four-story and four-span steel frame-concrete shear wall structure is subjected to fire analysis. The calculation results of the derived formula are compared with the results of the finite element analysis. The results are verified by each other. Based on APM, the initial failure is introduced into the structure through the time history analysis function. At the same time, the dynamic response of the structure after the damage and failure is given. The whole failure process of structure under the action of secondary fire disaster is analyzed. The failure mode of damaged structure under fire high temperature and the safe escape time are given. The failure process of damaged structure and intact structure under fire high temperature is compared and analyzed through the comparison and analysis of the failure process of damaged structure and intact structure under the action of fire high temperature. The effects of initial failure on the high temperature behavior of structures are studied. By comparing the structural responses in different fire environments and fire locations, the initial heating rate and edge span are studied. The effect of middle span fire on the fire resistance of steel frame structure A method for calculating the internal force and deformation of the steel frame structure during the whole process from the initial time of heating to the failure of the fire member under the action of high temperature in fire is presented. The influence of normal working stress level on the failure temperature is discussed, and based on the DCR criterion, The evaluation method of continuous collapse of in-service steel frame structures under fire and high temperature is given. The concrete method of evaluation is illustrated by an example, and the influence of the change of beam span on the internal force and failure form of steel frame structure under fire is discussed.
【学位授予单位】：哈尔滨工程大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU391

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