When a structure is subjected to an explosion, high blast pressure is initially released during a very short period of time and is followed by fire. The combined effects of blast and fire may cause damage and failure of one or more key elements of the structure leading to progressive collapse and failure of the entire structure. However, design procedures suggested by current standards and codes do not consider the combined effects of blast and fire because of the complexity of the problem, which involves inertia and heat effects with high geometrical and material nonlinearities. The ultimate aim of the present study is the numerical and analytical prediction of the behaviour and failure of steel columns subjected to blast pressure followed by fire. A new numerical model was developed and validated to perform both dynamic and transient thermal analyses simultaneously using the dynamic fully coupled thermal-displacement analysis procedure within ABAQUS/explicit. The proposed numerical model was validated against published experimental test results. The study also proposes a new simplified approach for analysing the combined effects of blast and fire on the response and critical temperature of steel columns. The suggested approach implements the single degree of freedom analysis method (SDOF) in conjunction with the resistance function of steel columns at elevated temperature. The proposed analytical method has been validated against published experimental results in addition to numerical simulation results conducted in this study, and the validation has shown very good correlation between the results. The validated analytical approach can be used in the preliminary analysis and design of steel columns under blast and fire.

当结构发生爆炸时，高爆炸压力最初会在很短的时间内释放出来，然后会发生火灾。爆炸和火灾的综合影响可能会导致结构的一个或多个关键元件损坏和失效，从而导致整个结构逐渐倒塌和失效。然而，当前标准和规范建议的设计程序没有考虑爆炸和火灾的综合影响，因为问题的复杂性涉及具有高度几何和材料非线性的惯性和热效应。本研究的最终目的是对钢柱在爆炸压力和火灾后的行为和破坏进行数值和分析预测。开发并验证了一种新的数值模型，可以使用 ABAQUS/explicit 中的动态全耦合热位移分析程序同时执行动态和瞬态热分析。所提出的数值模型已根据已发表的实验测试结果进行了验证。该研究还提出了一种新的简化方法，用于分析爆炸和火灾对钢柱响应和临界温度的综合影响。建议的方法结合钢柱在高温下的阻力函数来实施单自由度分析方法 (SDOF)。除了本研究中进行的数值模拟结果外，所提出的分析方法已针对已发表的实验结果进行了验证，并且验证表明结果之间具有很好的相关性。经验证的分析方法可用于爆炸和火灾下钢柱的初步分析和设计。