EFFECT OF LOADING RATE ON RESTORING FORCE CHARACTERISTIC OF RC PORTAL FRAME ANDFRAMED SHEAR WALL.

(负责人：M·Ono，F.Esaki)根据试验结果得出以下结论：1)在高速率荷载作用下，无洞口剪力墙和有洞口剪力墙的横向承载能力大于慢速荷载作用下的水平承载力。其增大系数与由观测应变速率计算出的增大系数吻合较好。2)在单调水平荷载作用下，无洞口剪力墙和有洞口剪力墙的水平承载能力均大于在往复水平荷载作用下的水平承载力。3)在低速反复荷载作用下，具有弯曲破坏和弯剪破坏的开口剪力墙转变为剪切破坏。4)将没有开口的弯曲-剪切破坏串联的剪力墙改为弯曲破坏模式。(负责人：A.Hiramatu)通过1个试件的试验，得到了钢筋混凝土门式刚架的恢复力特性。/3尺度在横向载荷和倾覆力矩作用下的正弦循环类型，具有几种幅值和频率组合。根据试验结果建立了反映其特殊性的恢复力特征理想化模型，并对7层单跨试验型钢筋混凝土建筑的地震反应进行了数值计算。计算结果表明，结构的刚度和强度随倾覆力矩的较大变化而波动，将导致倾覆力矩的最大响应值减小。反之，波动会使Stoy漂移的最大响应值增大。

(The person in charge : M. Ono, F. Esaki)The following conclusions reached at results of the experiments.1)The lateral load carrying capacity of shear walls without opening and with an opening subjected to the load at the high rate was lager than that at the slow rate. Its increased factor agreed well with the increased factor calculated by the observed strain rate. 2)The lateral load carrying capacity of shear walls without opening and with an opening subjected to monotonic lateral load was larger than that subjected to the reversed cyclic lateral load.3)The shear walls with an opening of the flexural failure and flexural-shear failure made series subjected to the reversed cyclic load at slow rate are changed to the shear failure made.4)The shear walls without opening of the flexural-shear failure made series are changed to the flexural failure mode.(The person of charge :A. Hiramatu)Restoring force characteristics of RC portal frames were obtained by the experimental tests on the specimens of 1/3 scale under both lateral loading and overturning moments of sinusoidal cyclic type having the several combinations of amplitudes and frequencies. And also earthquake responses of 7-story one bay pilot type RC buildings were calculated numerically using the idealized model of restoring force characteristics that had been constituted to represent peculiarity obseved on the experimental test results.The results from these calculaions indicate that the fluctuation of stiffness and strength of the building structures in response to a wide variation of the amount of overturning moment would cause the maximum response values of overturning moment to decrease. On the contrary, the fluctuation would cause the maximum response values of stoy drift to increase.