1994 Fiscal Year Final Research Report Summary
Fundamental Study on Dynamic Damping Characteristics of Soil Ground at a Water Front
| Project/Area Number |
04650524
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Building structures/materials
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| Research Institution | Kobe University |
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Principal Investigator |
KUSAKABE Kaoru Kobe University, Faculty of Engineering, Professor, 工学部, 教授 (80027250)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Yukinori Kobe University, Faculty of Engineering, Research Associate, 工学部, 助手 (00116253)
FUKUSUMI Tadahiro Kobe University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (40031140)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Pile Foundation / Embedded Foundation / Vibration Generator Test / Characteristics of Vibration / Complex Stiffness / Thin Layr Element Method / Nonlinearity of Soil / Theory of Shell |
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| Research Abstract |
A purpose of this project is to obtain fundamental materials and data useful for the rational design of buildings supported by the pile foundation. Estimation of damping and presentation of a model of soil-pile foundation system which significantly effects on the dynamic response are proposed through the experimental and theoretical investigations on the complex stiffness of soil-pile system. From this research, followings are summarized.
1. Dynamic charcteristics of floating and end bearing piles installed in surface strata are determined by parametric study within a wide range of parameters. It becomes clear that the dynamic characteristics of pile are determined quantitatively by three parameters, i.e. wave number for effective length of pile, stiffness of pile to that of soil and the slenderness ratio(pile length/radius).
2. Complex stiffness of soil-pile foundation system in vertical and horizontal vibration corresponding to the experimental results has been evaluated by recurrence
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analysis which adopts the least square method, the analysis using this complex stiffness is confirmed to give good results for the steady state response of pile foundation at any frequency.
3. Concerning to the nonlinear analysis of pile foundation, thin layr element method which consists of cylindrical elements around the pile is developed to take into account the variation of soil properties in the radius direction. From the result of response due to forced excitations at the pile head, it is found that the nearer to the ground surface or the pile and the higher excitation frequency, the easier to become nonlinear.
4. Embedded cylindrical structure with several diameters are analyzed by the thin layr element method as in the above. Since the analysis of the structure is dealt with the shell theory, distribution of displacements in the three directions, membrane stress and bending stress of the shell can be obatined and the distribution characteristics of responses corresponding to the diameter of shell become clear. Less
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