Development of impact-resistant design procedure of RC members using relationships among static bending/shear capacity, input energy, and absorbed energy

为了建立合理的钢筋混凝土静弯破坏模式和剪切破坏模式的抗冲击设计方法，进行了以配筋率、剪跨比、截面尺寸和钢材质量为变量的各种钢筋混凝土矩形梁的落锤冲击试验。冲击荷载作用于钢筋混凝土简支梁的跨中，采用200、300、400 kg三种不同质量的钢材，分别采用迭代加载法和单一加载法进行加载。另一方面，为了建立合理的钢筋混凝土梁在冲击荷载作用下的数值分析方法，对钢筋混凝土梁的弹塑性冲击响应进行了CAR…分析并采用三维有限元方法进行了数值模拟。本文的研究结果如下：1)用最大破坏反力估算受冲击荷载作用的钢筋混凝土梁的极限强度；2)利用极限状态下梁的最大反力、吸收能和梁跨中残余位移之间的关系，经验地提出了钢筋混凝土梁的抗冲击设计公式。3)利用本文提出的简化有限元分析方法，可以较准确地预测钢筋混凝土梁的冲击力、反力和位移时程。根据最大主应力分布可以预测钢筋混凝土梁侧面产生的裂缝形态。较少

In this study, to establish a rational impact-resistant design procedure of Reinforced Concrete(RC)beams with statically bending-failure-mode and shear-failure-mode, falling-weight impact tests on various kinds of rectangular RC beams are conducted in which rebar ratio, shear-span ratio, cross sectional dimensions, and mass of steel weight are taken as variables. Impact load is surcharged onto the mid-span of simply supported RC beams using three kinds of steel weights varying mass : 200, 300, and 400 kg and applying two types of loading methods : iterative loading method and single loading method. In this experiment, impact force occurred in the steel weight, reaction force at support points, and displacements of RC beams are measured and recorded by wide-band analog data recorder.On the other hand, to establish a rational numerical analysis method for bending-failure-type and shear-failure-type RC beams under impact loading, elasto-plastic impact response analyses on RC beams are car … More ried out by means of three-dimensional Finite Element Method(FEM). The applicability of the proposed method using a simple constitutive law is discussed comparing with the experimental results mentioned above.The results obtained from this study are as follows : 1)Ultimate strength of bending-failure-type and shear-failure-type RC beams subjected to impact load can be estimated by using the maximum reaction force at failure ; 2)The impact-resistant design formulas for bending-failutre-type and shear-failure-type RC beams are empirically proposed using relationships among the maximum reaction force, absorbed energy, and residual displacement of the mid-span of beam at ultimate state. And theirs practical applicability is confirmed comparing the experimental results ; 3)Time histories of impact force, reaction force, and displacements of RC beams can be accurately predicted by means of the proposed simple FE analysis method. And also, crack patterns generated in the side-surface of RC beam can be predicted from maximum principal stress distribution. Less