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

Tomosawa研究了在高强混凝土圆柱体抗压试验中使用非粘结式封顶方法，发现使用硬橡胶的抗压强度接近于通过抛光圆柱体端部获得的抗压强度。研究了高强混凝土的材料和配合比。加藤将弯曲屈服后的破坏模式分为(a)混凝土破碎破坏、(b)剪切破坏和(c)粘结破坏，并提出了估算每种破坏模式下极限变形的表达式。对钢筋混凝土柱进行了变轴向荷载和双向侧向荷载逆转试验，并校核了设计极限轴向荷载水平。结果表明，纤维模型能有效地模拟柱的受弯性能。对试验梁沿纵向配筋的粘结强度进行了研究，重点研究了纵向配筋数量的影响和剪力配筋的影响。Yoshimura对外梁柱节点梁纵向钢筋的拉拔强度进行了研究。提出了一个简单的模型来模拟这种行为。Kitayama对内部梁柱连接进行了试验，研究了梁杆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受弯后极限变形的估算方法和钢筋混凝土建筑的抗震设计要求。

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.