Development of Earthquake Resistant Design Method of Reinforced Concrete Buildings using Ultra-high-strength Materials

Tomosawa研究了在高强度混凝土圆柱体的压缩试验中使用非粘结型封盖方法，发现使用硬橡胶的压缩强度接近于通过抛光圆柱体端部获得的压缩强度。研究了高强混凝土的原材料和配合比，Kato将弯曲屈服后的破坏模式分为混凝土的压碎破坏、剪切破坏和粘结破坏，并提出了相应的极限变形表达式。对钢筋混凝土柱进行了变轴向荷载和双向侧向荷载作用下的试验，并对设计极限轴向荷载水平进行了检验。通过一之濑试验梁研究了纵向钢筋沿着方向的粘结强度，重点研究了纵向钢筋数量的影响和抗剪钢筋的作用。Yoshimura研究了梁柱外节点梁纵筋的抗拔强度。提出了一个简单的模型来模拟这种行为。北山对内部梁柱连接进行了试验，以研究梁钢筋的锚固要求和连接的抗剪强度。野口对材料模型进行了非线性有限元分析。Otani和Aoyama研究了钢筋混凝土柱弯曲屈服后极限变形的估算方法和钢筋混凝土建筑物的抗震设计要求。

The use of unbond-type capping method in compression test of high-strength concrete cylinders was examined by Tomosawa, and the use of hard rubber was found to give compressive strength close to the one obtained by polishing the cylinder ends. The materials and mix proportions were studied to develop high strength concrete.The failure modes after flexural yielding were classified to (a) crushing failure of concrete, (b) shear failure, and (c) bond failure by Kato, and an expression was proposed to estimate the limiting deformation associated with each failure mode. Reinforced concrete columns were tested under varying axial load and bi-directional lateral load reversals, and the design limiting axial load level was examined. The analysis by the fiber model was found to be effective simulating the flexural behavior of the columns.Ichinose tested beams to study the bond strength along longitudinal reinforcement, with emphasis on the effect of the number of longitudinal reinforcing bars and the effect of shear reinforcement. The pull-out strength of beam longitudinal reinforcement from an exterior beam-column joint was studied by Yoshimura. A simple model was proposed to simulate the behavior. Kitayama tested interior beam-column connections to study the anchorage requirements of beam bars and the shear strength of the connection.Noguchi examined the material models for a nonlinear finite element analysis. Otani and Aoyama studied the method to estimate the ultimate deformation of reinforced concrete columns after flexural yielding and the earthquake resistant design requirements for reinforced concrete buildings.