Research on Structures and Foundations Considering with Gravity Restoring Effect during Large Earthquake

第一部分：已经阐明，在大地震期间允许基础抬升将减少建筑物的破坏。有几项研究认为，地基条件是完全稳固的。在本研究中，假设地基为弹性，地基的垂直刚度为主要参数，并在振动台上进行了试验。第二部分：在基础隔震结构的抗震设计中，一般不考虑大地震作用下橡胶支座的拉力。在某些情况下，在建筑形状的高宽比较大的建筑中，可能会允许橡胶支座中的拉力。在本研究中，研究了隔震结构在底部引起基础上浮时的行为。进行了隔震界面参数为适当周期、地基垂直刚度为参数的模型试验。利用正确评价重力恢复效果等理论，得到了能够计算实验结果的数值分析结果。

Part 1 : It has already been clarified that allowing the uplifting of foundations during large earthquake would decrease the damage of the building. There were several researches that the ground condition was assumed to be perfectly firm. The ground was assumed to be elasticity in this research, a perpendicular stiffness of the ground was assumed to be a parameter chiefly, and they were experimented on the shaking table. In addition, the analysis that considered the effect of uplifting of foundation was done, and the influence from an experiment and an analytical result to the building by the phenomenon of uplifting of foundation was examined.Part 2 : In seismic design of the base isolated structures, generally tension force in rubber bearing is prohibited under large earthquake. In some case, tension force in the rubber bearings might be allowed in the building where the aspect ratio of the building shape is large. In this research, behavior when uplifting of foundation is caused at the base of the seismic isolated structures is examined. The model experiment of which the parameters a proper period of seismic isolation interface, and was a perpendicular stiffness of the ground was done. The numerical analysis result that it was able to calculate the experiment result was obtained by using the theory that correctly evaluated the effect etc. of the restoration of gravity.