高速公路收费站网架雨棚抗火性能及灾后评估

发布时间：2018-05-29 16:24

本文选题：高速公路收费站 + 网架结构抗火　；参考：《山东大学》2015年硕士论文

【摘要】：高速公路收费站多采用网架结构的结构形式,是因其具有整体刚度强、多向受力性能好及制作安装方便等优点。高速公路收费站作为重要的交通枢纽,一旦发生火灾,在人员撤离前若网架发生倒塌,可能造成严重人员伤亡和财产损失。此外,高速公路收费站雨棚不同于一般的室内建筑,空间开敞导致火灾时其受当地环境影响大,特别是大风和风向的影响。高速公路常见的车辆有油罐车等危险车辆,发生火灾时若波及附近的危险车辆,可能会导致发生烃类火灾。火灾温度曲线会因高风速、炎热、石油、燃气空气中的挥发等因素导致轰燃使环境温度快速上升。由此可见,对高速公路网架结构进行抗火性能分析具有重要的意义。火灾后,高速公路收费站灾后修复时间和安全性评估也尤为重要。作为高速公路重要的枢纽,收费站的修复工作将直接影响道路是否能正常运行。所以用尽量短的时间,结合经济性因素考虑,采用合理的加固修复方案也具有重要实用价值。目前对于网架的研究主要集中在一般网架结构的结构设计、施工方法、抗火等方面,而高速公路收费站雨棚的一些结构尺寸不同于普通网架,是由收费站的特殊使用功能决定的,使得一些变形和受力特点也不同于普通网架,因此,有必要对高速公路收费站网架的抗火性能进行深入研究,掌握结构在火灾发生时的抗火能力；并采用合理的加固修复方案。本文结合具体的工程实例,采用参数分析的方法,对高速公路收费站火灾中常见网架钢结构的抗火性能和灾后评估进行了研究。研究对象涵盖了不同的工况参数(全跨网架、半跨网架和四分之一网架火灾),时间参数(15min、30min)和不同的加固修复方案。首先根据实际情况确定结构荷载情况,并按《建筑钢结构防火技术规范》规定的荷载组合,采用有限元软件ABAQUS进行常温下的结构受力分析。第二步利用ABAQUS进行火灾下的结构受力性能分析。通过采用恒载升温的方式,使整个结构按实际情况升温,结构丧失承载力时的温度为结构的临界温度,对应的火灾时间为结构的耐火时间,观察结构变形及受力特点,耐火能力和破坏形态,对比不同参数的差异。第三步采用一种常见的火灾情况和网架,利用有限元软件模拟火灾进行到600℃左右扑灭,结构降温到环境温度,不考虑钢材强度的折减。观察残余应力的大小和分布情况,确定加固方案。并对修复后的结构重新加载,得到加固后的应力,验证加固方案效果。
[Abstract]:The freeway toll station adopts the structure form of the net frame, because it has the advantages of strong overall stiffness, good multi force performance and convenient production and installation. As an important transportation hub, the freeway toll station may cause serious casualties and property loss if the grid happens to collapse before the evacuation of the personnel. In addition, the rain shed of the freeway toll station is different from the general indoor building. Space opening causes the fire to be affected by the local environment, especially the influence of the wind and wind. The common vehicles in the expressway are dangerous vehicles, such as oil tank cars. If the dangerous vehicles are affected in the vicinity of the fire, the fire temperature may lead to fire. The curve will cause the rapid rise of the environment temperature because of the high wind speed, heat, oil and gas air. Thus, it is of great significance to analyze the fire resistance performance of the expressway network frame structure. After the fire, the repair time and safety assessment of the expressway toll station are also particularly important. The repair work of the toll station will directly affect the normal operation of the road. So using the shortest time and considering the economic factors, it is also of great practical value to adopt the reasonable reinforcement and repair scheme. At present, the research on the grid is mainly focused on the structure design, construction method and fire resistance of the general network frame structure. The structure size of the rain shed in the toll station of the freeway is different from that of the ordinary net frame, which is determined by the special function of the toll station, which makes some deformation and stress characteristics different from that of the ordinary net frame. Therefore, it is necessary to study the fire resistance performance of the network frame of the freeway toll station and to grasp the resistance of the structure in the case of fire. In this paper, the fire resistance and post disaster evaluation of the common grid steel structure in the toll station fire are studied with the method of parameter analysis. The research object covers the number of different working conditions (full span network frame, half span network frame and 1/4 net). Frame fire), time parameters (15min, 30min) and different reinforcement and repair schemes. First, according to the actual situation, the structure load is determined. According to the load combination of the fire protection technical specification of the building steel structure, the finite element software ABAQUS is used to analyze the structural stress of the structure under the normal temperature. Second steps are used to use the ABAQUS to carry out the structural stress under the fire. Through the method of constant load heating, the whole structure is heated up according to the actual condition, the temperature of the structure loses its bearing capacity as the critical temperature of the structure, the corresponding fire time is the fire time of the structure, the structure deformation and the stress characteristics, the fire resistance and the failure form are observed, and the difference of the different parameters is compared. Third steps adopt a kind of constant. The fire situation and the grid frame, using the finite element software to simulate the fire to be extinguished about 600 degrees centigrade, the structure cooling to the ambient temperature, without considering the reduction of steel strength, observe the size and distribution of the residual stress, determine the reinforcement scheme, reload the structure after the repair, get the stress after reinforcement, and verify the effect of the reinforcement scheme.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU356;TU352.5

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