| Project/Area Number |
03650385
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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 |
土木構造
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
BOLANDER John Jr. (1992) Jr.,Kyushu University, Department of Civil Engineering, Assistant Professor, 工学部, 講師 (30220990)
丸山 義一 (1991) 九州大学, 工学部, 助手 (70209708)
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| Co-Investigator(Kenkyū-buntansha) |
OTSUKA Hisanori Ministry of Construction, Building Research Institute, Division Head, 国際地震工学部, 室長 (70108653)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1992: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1991: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Pile Foundation / Pile Group / Limit State Design / P-Y Curve Method / Randolph's Equation / 基礎構造 / 杭の変位照査 / 差分法 |
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| Research Abstract |
In Japan, research towards introducing limit state concepts into the design codes is being carried out, including research concerning pile foundations. Lateral loading tests on single piles and pile groups have been executed by several organizations and the large deformation behavior of pile foundations has been clarified.
In this study, an analysis method for accurately simulating the horizontal behavior of pile foundations is proposed. The nonlinear characteristics of both the ground and the pile are taken into account in the analysis of a single pile with large horizontal deformation. The P-Y Method of DNV is applied to consider the characteristics of the ground, which is modeled by a distribution of Winkler-type springs connected to the pile; the M-phi relation of the pile is assumed to be either bilinear or trilinear. Pile lateral displacements predicted by the analysis method agree quite well with experimental results obtained by other researchers. Bending moments and subgrade rea
… More
ctions are also predicted fairly well.
For the pile group analysis, it is also necessary to consider the effect of interaction between each pile. For this purpose, it is assumed that the displacement of a pile group can be divided into two components: 1) the displacement due to ground plasticity without the interaction of piles, and 2) the displacement due to the interaction of piles in elastic ground. The former is calculated by the P-Y Curve Method and the latter by using Randolph's Equation in which the soil is assumed to be an elastic continuum. Straightforward application of this method underestimates the pile group lateral displacement because load-allotment within the pile group is not considered. To consider this factor, the shear modulus of the soil is reduced with increasing lateral load. As the actual procedure is complicated, simple relations for reducing the shear modulus are proposed. Lateral pile group displacements from this method (using modified shear modulii) agree quite well with experimental values. Reasonable results are also obtained for pile bending moments and subgrade reactions. Less
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