爆炸荷载作用下钢筋混凝土柱的动力响应与破坏模式

在爆炸荷载作用下,钢筋混凝土构件和结构的动力响应较之地震荷载和静态荷载作用下要复杂得多。运用有限元显式动力分析软件LS-DYNA,建立了典型钢筋混凝土柱的三维有限元模型,该模型对钢筋混凝土采用分离式建模,并且考虑了材料的应变率效应和钢筋与混凝土间的粘结滑移。在该有限元模型的基础上,通过对爆炸荷载作用下钢筋混凝土柱动态响应的数值模拟,研究了钢筋混凝土柱在爆炸荷载作用下可能的破坏模式及其规律。同时,运用参数化分析方法,研究了截面惯性矩、混凝土轴心抗压强度、纵筋配筋率和配箍率等参数对钢筋混凝土柱在爆炸荷载作用下的动态响应的影响,在数值模拟结果的基础上,分析提出了钢筋混凝土柱抗爆设计时应当注意的问题。研究结果表明:在爆炸荷载作用下,钢筋混凝土柱的破坏模式不仅和自身的特性有关,还取决于爆炸荷载的类型。提高柱截面惯性矩和混凝土轴心抗压强度,能够显著降低钢筋混凝土柱在爆炸荷载作用下的柱中水平位移,从而提高其抗爆性能。增加配箍

Dynamic responses and failure modes of RC columns under blast loading

The dynamic response of reinforced concrete(RC) member and structure under blast loading is much more complicated than that under other loadings such as earthquake loading and static loading,since the blast wave propagates fast and the load acting on the structure appears at the peak value for a short duration.In this paper,3D numerical models of typical RC columns are established by using software LS-DYNA.In the model,the steel bar and concrete are modelled separately,and the bond slip between them is considered.The strain rate effects of the two materials are also included in the numerical model.Based on the model,numerical simulations are carried out to learn the possible failure modes of RC column under blast loading.Parametric studies are also adopted to investigate the effects of moment of section inertia,concrete strength,longitudinal and transverse reinforcement ratio on the dynamic response of RC column under blast loading.Some suggestion on designing the RC column to resist blast loads is proposed based on the numerical results.It is found that the failure modes of RC column under blast loading depend not only on the column properties,but also on the blast loading type.The results also show that by increasing the moment of section inertia and concrete strength,the lateral displacement of mid RC column can be dramatically decreased under blast loads;by increasing the moment of section inertia,concrete strength and transverse reinforcement ratio,the blast resistant capacity of the RC column can be increased.