RC框架楼房中心立柱爆破失效条件下结构动力响应特性分析

Analysis on Structural Dynamic Response Characteristics of RC Frame Building under Blasting Failure Condition

为研究RC框架楼房局部立柱爆破失效后结构的抗连续倒塌性能和动力响应特性,依托一栋8层框架结构楼房爆破拆除工程,通过中心立柱现场爆破试验,对立柱邻近梁柱子结构的变形与应力调整过程进行了实时观测。采用PKPM建立实际工程对应的建筑模型,并基于拆除构件法,应用SAP 2000中非线性动力分析方法计算中心立柱失效下剩余结构的动力响应特性以及抗连续倒塌能力。结果表明:中心立柱爆破失效后,采用应变-弯矩理论公式得出的应变理论值约为260με、动应变现场实测值约为377με、数值模拟值约为238με,三种方法得出的动应变结果较为接近;失效点竖向位移计算值3.2 mm,与现场实测位移2.67 mm接近,其导致的塑性转角计算值为0.051°,与现场实测值0.05°接近;中心立柱爆破失效瞬间,剩余结构经历了明显的动力冲击,其正负向加速度值大致相同,最大加速度达到3.5 m/s^(2);中心立柱失效后,剩余结构产生荷载重分布,原本由中心立柱承担的竖向荷载被周边柱所分担,导致上方梁体出现显著的悬链线效应。本论文的研究成果有助于框架结构楼房在意外爆炸情况下的易损性评估与抗连续倒塌性能分析,同时也可为拆除爆破中的试爆立柱选择提供参考。

To study the continuous collapse resistance and dynamic response characteristics of the structure after the blasting failure of the local columns of the RC frame building,the deformation and stress adjustment process of the beam-column substructures adjacent to the columns were observed in real-time through an on-site blasting test of the central column of a blasting and demolition project of an 8-storey frame building.The PKPM was used to establish the corresponding building model.Meanwhile,the dynamic response characteristics of the remaining structure under the failure of the central column and the resistance to continuous collapse was calculated by the demolition component method and the demolition component method in SAP 2000.The results show that the theoretical value of strain after the blast failure of the center column is about 260μεusing the strain-moment theoretical formula.The dynamic strain measured in the field is about 377με,and the value calculated by the numerical simulation is about 238με.The results of the dynamic strain by the three methods are relatively close.The computed value of the vertical displacement at the failure point is 3.2 mm,close to the field displacement of 2.67 mm,and the calculated value of the plastic angle is 0.051°,close to the field angle of 0.05°.The remaining structure experienced a significant dynamic impact at the instant of the central column failure,and the acceleration values along the positive and negative directions are roughly the same,with a maximum value of 3.5 m/s.After the failure of the central column,the load redistribution occurs in the remaining structure,and the vertical load originally borne by the central column is shared by the surrounding columns,resulting in a significant catenary effect on the upper beam body.