1997 Fiscal Year Final Research Report Summary
Vibration model of pile foundation considering nonlinearity of soil
| Project/Area Number |
07650662
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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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, Dept.of Architecture and Civil Engineering, Faculty of Engineering, Professor, 工学部, 教授 (80027250)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Yukinori Kobe University, Dept.of Architecture and Civil Engineering, Faculty of Engineer, 工学部, 助手 (00116253)
FUKUSUMI Tadahiro Kobe University, Dept.of Architecture and Civil Engineering, Faculty of Engineer, 工学部, 助教授 (40031140)
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| Project Period (FY) |
1995 – 1997
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| Keywords | Pile foundation / Pile-structure system / Under ground structure / Nonlinearity of soil / Nonlinear response / Hyogoken Nanbu Earthquake / Analisis model / Thin layred element method |
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| Research Abstract |
The purpose of this research is to present the evaluation method of complex stiffness and input motion as dynamic properties of pile foundation considering the non-linearlity with respect to rigidity and damping of soil and to present the vibration model of pile foundation applicable to earthquake resistant design. Results obtained in this term are summarized as follows.
1. Concerning the nonlinear response analysis of ground, effective stress analysis is adopted. The characteristics of response of filled ground under drastic earthquake such as Hyogoken Nanbu Earthquake are pointed out as follows ; Distribution of the horizontal acceleration reduces towards ground surface, the depth where the maximum curvature response occurs corresponds to the depth where the bending fracture of pile happens and more accurate hysteresis loop of ground can be obtained when the cyclic mobility is considered.
2. Earthquake response of buildings with pile foundation is analyzed by thin layred element method. The followings are grasped by this analysis. i.e.the more the rigidity of the soil reduces, the more the input horizontal acceleration is reduced and the isolation effect of ground is develops. Through various investigations, this method using the thin layred element method and considering the soil nonlinearity by equivalent linealization procedure is found to be useful for the non linear earthquake response analysis of pile foundation.
3. For the response analysis of building with basements, it is replaced by cylindrical tube and the ground beneath it is assumed as a soil column. This method uses the thin layred element method and takes equivalent rigidity and damping corresponding to the soil non-linearity. From the comparative study of observed results of earthquake and analytical results, this analysis method is justified to be useful for earthquake response analysis of building with basements.
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