| Budget Amount *help |
¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1986: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1985: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
A purpose of this project is to evaluate quantitatively equivalent stiffness coefficient and viscous damping coefficient on a soil ground, analytically and experimentally. Following results are obtained.
1. Dynamical ground compliance which is a dynamic property of a soil ground and which is dependent on frequency, is represented by an approximate rational function, and then is replaced by a vibration system which consists of springs and dashpots which are independent on frequency. This method makes the earth-quake response analysis of the soil-structure interaction system possible.
2. Considering that a cylindrical basement is buried in a soil ground with a softer zone between it and it's outer soil medium, the effect of sidefill rigidity on vibration characteristics of a soil-basement system is discussed. It is pointed out that the smaller the wave velocity of the softer zone to that of the outer soil medium, the greater the real part of the displacement response at the top of the basement, in lower frequency.
3. Vibration tests on embedded foundations are carried out by using of a vibration generator. A feature of this experiment is to treat with the two cases for the foundation having a gap between it and it's outer soil ground, and the foundation filled up around it. The effect of sidefill on the amplitude characteristics is discussed.
4. From these vibration characteristics, an equivalent spring coefficient and a viscous damping coefficient are calculated, especially, both coefficients are separeted into a part of contribution at the bottom and a part of that at the side of the foundation. It is pointed out that the effect of sidefill on equivalent spring and viscous damping coefficients is greater for horizontal excitation than vertical one, and also is greater for viscous damping than spring coefficient.
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