| Because of its light weight, good ductility and high mechanization degree, steelstructure is applied by many architects gradually. It often appears in the complex structures,such as the high-rise public buildings, man-sized industrial plants, large space commercialcenters and so on. However, steel’s watery poor resistance is the biggest obstacles for its owndevelopment. Improving steel’s fire performance and determining the structure stressperformance under the fire become the focus of attention for scientific research personnel. Myresearch project is put forward under such a context. In the paper, according to practicalengineering, the author sums up the influence factors of its fire resistance ability by analyzingfire performance of the space structure. And after fire disaster, author estimates the damagedegree of steel structure on the basis of standards. Finally, author comes up with the completeimplementation process to research the structure’s fire resistance performance. Such resultwill be helpful to practical application.Current fire prevention design method in our country is based on the components ofmany fire tests. Nevertheless, the constraint function of other component is not considered inthe tests, and test temperature has bigger difference with actual fire temperature. Therefore,such method has poor reliability and practical utility, and its price is much expensive.Particularly, it is not applied to research the fire performance of large space structure. Forsolving this difficult problem, the researchers raise the performance-based fire resistancemethod. Through making use of hot-force coupling module in the finite element software tocalculate model, the author can understand the change of mechanical parameters in the fire. Atthe same time, for guiding buildings’ repair work, I study the stress of structure after disasters.Based on this advantage, numerical simulation method is adopted in my thesis.The author uses two kinds of finite element software (ABAQUS and ANSYS) tocalculate section temperature of the thin-walled steel tube. By comparing two result, we kwonthe heat-transfer method is accurate and feasible, so it will provide the boundary conditionsfor the structure’s fire resistance research.Making use of thermal analysis module in ABAQUS software, the author calculates itssection temperature of a layer of the steel components, and compares their highesttemperature between coating components and bare components to show that coating haveimportant role to reduce steel temperature. And then, analyzing the fire temperature ofcomponents which have four kinds of coating thickness, we can get such a conclusion: sectiontemperature reduction is not in proportion to coating thickness increase. In addition, throughcomparing two results calculated by computer and formula, the author checks reliability of thesoftware results and practicability of the formula.Regarding the space rack as research project, the author analyzes its mechanicalproperties in the fire. By observing related parameters, we may sure the influence factors ofthe structural fire resistance performance. It contains: the nonhomogeneity of temperaturefield, the restriction of bearing and the number of the force transmission path. The authorresearches the member stress after fire, and judges the structural ultimate bearing capacityaccording to criterion. They will help to direct structural repair work. Moreover, the author researches the mechanical properties of the steel truss in the fire.Through calculating members’ fire temperature and loading to analyze, we can kwonstructural stress state in the whole process and provide repair advice.After the engineering practice, the author put forward to a complete set of researchmethod for space structure fire resistance performance. Such method will be important forstructural fire resistance design. |
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