在爆炸冲击荷载作用下,结构底层柱的破坏可能会导致结构的连续倒塌。本文综合考虑了不同柱端约束条件和不同折合距离的影响,运用LS-DYNA分析了爆炸荷载作用下三组钢筋混凝土柱的动态响应及破坏模式。混凝土采用脆性损伤模型并考虑损伤及应变率效应,通过建立三维实体柱模型,得到动力系数、柱破坏模式及不同折合距离的柱中节点位移时程曲线。结果表明,相同的T/Tw,爆炸荷载作用下两端固接柱的动力系数比一端固接一端铰接柱的大,钢筋混凝土柱在爆炸冲击荷载作用下的侧向位移随着折合距离的增大而逐渐减小,当折合距离Z〉2.0时,爆炸冲击荷载对柱的影响可以忽略。
The failure of the reinforced concrete column at bottom floor under blast load may result in progressive collapse of the whole building. In the paper,the finite element program LS-DYNA is used to simulate the dynamic response of three RC columns with different constraint condition and scaled distance subjected to blast pressure. A three dimensional solid model,with concrete considering brittle damage and strain rate effect,is established to calculate dynamic factor,failure mode of columns well as displacement response spectrum curves of different scaled distance. The results show that the dynamic factor of column with rigid connection on both sides is bigger than the rigid connection on one side and simply support on the other side under the same T / Tw. Furthermore,the lateral displacement decreases gradually with the increase of scaled distance. The impact of blast pressure on column can be neglected when scaled distance exceeds the value of 2. 0.