对钢筋混凝土框架结构在集中对称撞击荷载作用下的非线性动力响应进行理论分析． 分析中考虑了落锤初始撞击速度及梁柱线刚度比的影响，并通过非线性有限元分析得到撞击力随时间变化的规律、结构的位移响应和最终变形，确定了结构塑性变形的特性及耗能情况． 通过分析计算结果，提出估算框架结构受撞击处最终变形的简化分析模型，进行了简化计算结果与有限元分析结果的对比，发现: 相对于梁柱线刚度比，初始撞击速度对结构撞击响应的影响较大; 框架结构的塑性变形主要集中在框架梁两端及跨中，且框架梁的塑性变形随着初始撞击速度的提高明显增大; 框架柱有对称向外的水平位移，塑性变形相对较小．

Dealt with in this paper is the nonlinear dynamic response of reinforced concrete frame structures under symmetrical centralized impacts.In the investigation,first,two influencing factors,namely the initial impact velocity of the drop hammer and the beam-to-column linear stiffness ratio,are analyzed.Next,a nonlinear finite element analysis is performed to explore the variations of the impact force with time,the displacement response of the structure,the final deformation,the characteristics of the plastic deformation and the energy consumption of the structure.Then,the computational results are analyzed and a simplified model to estimate the final deformation of the impact point is put forward.Finally,a comparison is made between the results respectively obtained by the finite- element computation and the simplified model.It is found that ( 1) the influence of initial impact velocity on the structure's dynamic response is more evident than that of the beam-to-column linear stiffness ratio; ( 2) the plastic deformation of the frame structure mainly occurs at the two ends and in the midpoint of the beam,which greatly increases with the increase of the initial impact velocity; and ( 3) the horizontal displacement of the two frame columns is symmetrically outward and the plastic deformation of the column is relatively smaller than that of the beam.