钢结构建筑建造速度快、抗震性能好、建筑造型美观且富于变化，随着我国钢产量的大幅度提高，建筑技术的不断进步，其应用前景非常广泛。但是，耐火性能差是钢结构的一个致命缺点，钢材的强度、弹性模量等基本力学性能指标在高温下急剧下降，一旦发生火灾，钢结构建筑就有可能发生严重的破坏，甚至过早地整体倒塌，造成严重的经济损失和人员伤亡。目前国内的钢结构抗火设计主要采用基于试验的构件抗火设计方法，这种方法费用昂贵并且很难模拟构件在整体结构中的荷载分布和大小、端部约束等情况。通过计算来确定钢结构的抗火极限承载力，可以更加合理地确定钢结构的防火保护措施。因此，对基于计算的钢结构抗火设计方法进行深入的研究，具有重要的理论意义和工程实用价值。 本文在综合考虑国内外钢结构抗火研究动态的基础上，根据传热学经典理论，从设计参数的选择与确定入手，利用ANSYS有限元软件，建立了钢框架在火灾条件下的传热模型、外力荷载及温度荷载共同作用下的受力模型，综合考虑材料非线性和几何非线性，对其进行整体抗火分析研究。 本文主要针对不同柱截面形式（箱型和H型截面）的平面钢框架进行ANSYS数值模拟分析比较，得到其不同的失效状态，分析研究了柱截面形式对钢框架抗火性能的影响。绘制出火灾发生时间与温度及变形的关系曲线，真正达到结构瞬时温度状况和结构火反应一体化。并通过对空间钢框架的温度－结构耦合计算，进行火灾情况下钢结构全过程反应分析，判断出火灾下结构的薄弱环节，考察受火构件与非受火构件的相互影响，更加真实地反映出结构的抗火性能。 本文研究成果对真实火灾作用下结构体系抗火极限状态的研究以及钢结构建筑抗火设计具有一定的指导意义和参考价值。

The architectural velocity of the steel structural construction is quick, its earthquake resistance performance is good, and its architectural modeling is beautiful and changeful. Its application prospect will be very extensive along with the output of the steel became more and more and architectural technology unceasing progress. But the poor fire-resistance ability is the main weakness of steel structure, its basic mechanical property such as strength and elastic modulus and so on decrease severely in high temperature. When fire occurs, the steel structure construction has the possibility to have the serious destruction, even the premature whole collapses, creates the serious economic loss and the personnel casualty. In china, test-based fire resistance design method is the prevailing fire resistance design method for steel structures. However, using the test-based fire resistance design method, it is costly and very difficult to simulate the magnitude and distribution of loads and the end restriction conditions of the specimens in the structure,etc. Through the computation determined the steel structure the fire-resistant limit supporting capacity, may reasonably determine the steel structure the fire protection protective measures. Therefore, a thorough study of the calculation-based fire resistance design method has great theoretical significance and practical value. In this article, based on the research dynamic condition of steel structures fire resistance in the domestic and foreign, according to the heat transfer study classical theory, obtaining from the design variable choice and the determination, using the ANSYS finite element software, has established the steel frame under fire condition heat transfer model, the external force load and under the temperature load together function stress model, synthetic considered the material non-linearity and the geometry non-linearity, researches the overall fire-resistant. This article mainly carries on the ANSYS value simulation analysis comparison to different column section form (box and H section) plane steel frame, obtained its different mode of failure, studies the influence of the column section pattern to the steel frame fire resistance performance. Draw up the relational curve of time-temperature, time-structural distortion in the fire, truly achieved the structure instantaneous temperature condition and the structure fire response integration. And through thermal-structural coupled calculation of the spatial steel frame, carry on entire process response analysis in the fire situation the steel structure, have judged weak link under the fire the structure, inspected the fire component with non-the fire component mutual influence, really reflect the fire-resistant performance of the structure. The researched results in this article have the certain guiding sense and the reference value to the structure system limiting condition research under the real fire function as well as the steel structural construction fire resistance design.