落石冲击下钢结构厂房结构动力安全研究

摘要

The time-history curves of impact force was measured with different conditions of tire protection by the experiment of rockfall shocking the plant model.The results showed that,the placement and increase of tire breaker can effectively defend the rockfall impact,but the additional protecting effect of the continued increase based on on a certain thickness appear inconspicuous.Meanwhile,on the basis of the measured impact force,three methods,which are structural mechanics calculation,pseudo-static finite element calculation,and dynamic finite element calculation,were employed to analyze the internal force and displacement of the experimental structure.The results showed that there is a big difference between the results of the three methods.Compared with the finite element analysis,the maximum internal forces by structural mechanics seem larger,while the maximum displacement appear smaller;the results by dynamic finite element are much different with the results by pseudo-static finite element,with their maximum displacement are significantly greater.The study showed that the tire breaker of proper thickness is well suited for the protection against the rockfall impact;it is obviously inaccuracy to solve the maximum response of structure by simplifying the rockfall impact load to the static load with its peak value.%通过落石冲击厂房的结构模型试验,测定了不同轮胎防护工况下结构的冲击力时程曲线.试验结果表明,安置和增添轮胎缓冲层能有效地防护落石冲击,但缓冲层增加到一定厚度后,继续增加得到的额外防护效果不显著.同时,在测得冲击力时程的基础上,分别采用结构力学法、有限元拟静力分析和有限元动力分析对试验结构的内力和位移进行了分析.分析结果表明,这3种方法所得结果存在显著差异.较有限元分析,结构力学法所得最大内力偏大,位移偏小;有限元动力分析结果与拟静力分析结果差别较大,其位移项明显大于拟静力分析结果.研究得出,适当厚度的废弃轮胎缓冲防护层非常适合保护厂房结构防落石冲击;将落石冲击荷载简化为其峰值处的静荷载来求解结构最大响应明显有失准确性.