基于性能的钢管桁架结构火灾响应分析

发布时间：2018-02-15 22:03

  本文关键词： 钢管桁架 稳态试验 瞬态试验 性能化设计 火灾分析　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：钢管桁架结构在结构形式与经济效益上具有明显优势,进行钢管桁架结构的火灾响应分析,是完善大空间钢结构抗火研究非常必要的一部分。本文以某会展中心为工程背景,对钢管桁架结构的火灾响应进行了研究,主要内容如下:分别采用稳态与瞬态两种试验方法对Q345管材进行了高温试验研究,试验结果表明各项力学性能由试验方法造成的差异非常明显。故基于瞬态试验提出了Q345钢管热膨胀系数、高温屈服强度与高温弹性模量的计算模型,并与国内外几种经典模型进行了对比,验证了其正确性与可行性。以某会展中心为工程背景,基于性能化的防火设计方法,制定了结构的防火安全目标,并对火灾的危险性、火灾荷载、火源位置、消防系统的有效性等各方面进行分析,从而确定了四种最不利的火灾场景。分析表明,采用ISO标准升温曲线与高大空间建筑火灾空气升温实用曲线进行大空间建筑温度场的模拟是不准确、不适用的。因此,本文以某会展中心工程为背景,利用FDS软件分析了大空间建筑温度场的分布规律。分析结果表明各火灾场景下温度场均呈现明显不均匀分布,且火源位置与火源面积对结构的升温都有一定的影响。并根据火灾下钢构件升温的实用计算方法,利用MATLAB软件计算了各构件的升温曲线,四种火灾场景下,构件温度最高可达334.41℃、292.60℃、240.24℃及211.26℃。利用ANSYS软件模拟了不同火灾场景下,结构整体的火灾响应规律与局部降温后结构的力学性能变化。模拟结果表明,钢管桁架结构在设计时,应适当增大支座附近弦杆截面积,减小外挑尺寸,在使用及维护过程中,尽量避免在屋盖支座附近堆积可燃物,可燃物面积不可过大,且较高展位应布置在净空较高区域。且对钢结构进行灭火时,应尽量避免在火灾全盛期对高温杆件直接进行喷水冷却。研究结果可为钢管桁架结构性能化防火设计与安全评估提供参考。
[Abstract]:The steel tube truss structure has obvious advantages in structure form and economic benefit. The fire response analysis of steel tube truss structure is a necessary part of improving the fire resistance of large space steel structure. In this paper, a conference and exhibition center is taken as the engineering background. The fire response of steel tube truss structure is studied. The main contents are as follows: the high temperature test of Q345 tube is carried out by using steady and transient test methods. The test results show that the difference of mechanical properties caused by the test method is very obvious. Therefore, based on the transient test, the calculation model of thermal expansion coefficient, high temperature yield strength and high temperature elastic modulus of Q345 steel pipe is proposed. Compared with several classical models at home and abroad, the correctness and feasibility of the model are verified. Taking a certain exhibition center as the engineering background, based on the performance-based fire prevention design method, the fire safety target of the structure is established, and the fire risk is also discussed. The fire load, the location of the fire source and the effectiveness of the fire control system are analyzed to determine the four most unfavorable fire scenarios. It is not accurate and applicable to simulate the temperature field of large space building by using ISO standard heating curve and practical curve of air heating in large space building fire. Therefore, this paper takes a conference and exhibition center project as the background. The distribution of temperature field in large space building is analyzed by using FDS software. The results show that the temperature field of large space buildings is distributed unevenly in every fire scene. And the location of fire source and the area of fire source have certain influence on the heating of structure. According to the practical calculation method of heating up of steel component under fire, the heating curve of each component is calculated by using MATLAB software. The maximum component temperature can reach 334.41 鈩，

本文编号：1513982