不确定爆炸荷载作用下钢梁的可靠度分析

通过对已有爆炸荷载预测公式、计算图表和试验的海量数据的统计分析,建立了作用于建筑结构上爆炸荷载的统计模型；以典型钢梁为研究对象,考虑材料强度和构件尺寸的不确定性,基于单自由度体系理论和蒙特卡洛方法,建立了不确定爆炸荷载作用下钢梁失效概率的计算方法,并开发了实用计算程序；分析了炸药质量以及爆炸荷载和结构材料属性的不确定性等对钢梁失效概率的影响。研究表明:炸药质量和比例距离是影响爆炸荷载作用下钢梁失效概率的重要因素,在建筑结构抗爆分析中,必须考虑爆炸荷载的不确定性。

RELIABILITY ANALYSIS OF STEEL BEAM UNDER UNCERTAIN BLAST LOADS

The statistical model of blast loads acting on building structures is established through the statistical analysis of a large number of blast load data from existing prediction empirical formulae of blast loads, calculation graphs and recent blast load tests. Based on the Single-Degree-of-Freedom (SDOF) system theory and the Monte Carlo method, the failure probability calculation method for a typical steel beam under uncertain blast loads is proposed, considering the uncertainties in both the material strength and the component dimension. The practical calculation program is also developed accordingly. Finally, parametric studies are carried out to investigate the influence of the explosive mass, the uncertainty of blast loads and structural properties on the failure probability of steel beams. Results show that the explosive mass and the scaled distance are two key factors affecting the failure probability of steel beams under blast loads, and the uncertainty of blast loads must be considered in the blast-resistant design analysis.