地震次生火灾作用下RC框架破坏机理分析

发布时间：2018-10-15 10:11

【摘要】：地震后次生火灾己经成为震后建筑物面临的主要威胁与灾害。地震和火灾的发生均为小概率事件,然而一旦发生地震,次生火灾却是发生概率最高的次生灾害之一。震后次生火灾造成的人员伤亡和财产损失有时远远超过地震本身造成的损失。目前国内外学者对建筑结构的抗震性能和抗火性能已经进行了广泛研究,但对于地震和火灾联合作用下的结构反应研究还很少。混凝土框架结构作为现代工程建设应用中最广泛的建筑结构之一,很有必要对其地震火灾联合作用下的结构性能展开研究。由于钢筋和混凝土的热力学性能存在较大差异,震后结构发生变形,在次生火灾作用下结构内力重分布复杂,加之没有成熟的分析方法,RC框架震后抗火性能的研究还处于起步阶段。本文基于大量的有限元模型分析,对地震火灾联合作用下RC框架的内力重分布情况和耐火性能进行了深入研究,主要研究内容如下:(1)本文基于ABAQUS有限元软件平台,建立了地震火灾联合作用下的RC框架模型。与两个试验得到的升温曲线和侧向力-位移曲线进行了对比,验证了所建模型的合理性和适用性。(2)利用本文建立的地震火灾联合作用模型和与之形成对比的仅火灾作用的模型,研究了局部起火情况下,框架不同受火位置对内力重分布的影响,包括柱单面受火、三面受火、四面受火,和梁顶面受火、底部受火,以及梁柱同时受火等多种局部起火情况。研究了RC框架地震和火灾联合作用下的内力重分布情况,并与火灾单独作用下的情况进行对比。(3)利用本文建立的地震火灾联合作用模型,深入分析了在恒温受火方式下,不同温度和受火时间对混凝土构件承载力退化和内力重分布情况的影响,并与火灾单独作用模型的情况进行对比。此外,还对不同地震程度下轴压比对RC框架耐火极限的影响进行了探讨。
[Abstract]:Post-earthquake secondary fire has become the main threat and disaster to buildings after earthquake. The occurrence of earthquake and fire are both small probability events, but once earthquake occurs, secondary fire is one of the most likely secondary disasters. The casualties and property losses caused by post-earthquake fire sometimes far outweigh the damage caused by the earthquake itself. At present, scholars at home and abroad have carried out extensive research on the seismic performance and fire resistance of building structures, but there is little research on the structural response under the combined action of earthquake and fire. As one of the most widely used building structures in modern engineering construction, it is necessary to study the structural performance of concrete frame structure under the combined action of earthquake and fire. Due to the great difference between the thermodynamic properties of steel bar and concrete, the structure is deformed after the earthquake, and the redistribution of the internal force of the structure under the action of secondary fire is complicated. In addition, without mature analysis methods, the research on the fire resistance of RC frame after earthquake is still in its infancy. Based on a large number of finite element model analysis, the internal force redistribution and fire resistance of RC frame under the combined action of earthquake and fire are deeply studied in this paper. The main contents are as follows: (1) this paper is based on the ABAQUS finite element software platform. The RC frame model under the combined action of earthquake and fire is established. Compared with the heating curves and lateral force-displacement curves obtained from the two experiments, the rationality and applicability of the proposed model are verified. (2) by using the earthquake fire combined action model established in this paper and the only fire action model compared with the model, In the case of local fire, the influence of different fire position of frame on the redistribution of internal force is studied, including fire on one side of column, fire on three sides, fire on four sides, fire on top of beam, fire at bottom, and fire by Liang Zhu at the same time. The redistribution of internal force under the combined action of earthquake and fire in RC frame is studied and compared with that in the case of fire alone. (3) by using the combined action model of earthquake and fire established in this paper, a deep analysis is made on the fire mode under constant temperature. The effects of different temperature and fire time on the degradation and redistribution of internal force of concrete members are compared with the model of fire alone. In addition, the influence of axial compression ratio on the fire resistance of RC frame is also discussed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.4;TU312.3

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