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Ishikawa K.,Kansai University | Ito A.,JAPAN PILE Corporation | Ogura H.,Kansai University
Journal of Structural and Construction Engineering | Year: 2012

Vertical loading tests were performed on the bearing capacity of straight pile with enlarged grouted base using pressurized sand tank for studying the effects of the tip length and the strength of enlarged grouted base. The main conclusions are as follows. 1) When the tip length was zero, "bond failure" occurred in the early stage of loading regardless of the strength, and the pile head load reduced abruptly. 2) When the tip length was 0.83 times the pile diameter and the strength was 15 N/mm2, "punching failure" finally occurred, but the same bearing capacity was obtained as in the case when the tip length was 1.3 times the pile diameter.3) When the tip length was 1.3 times the pile diameter, and the strength was 15 N/mm2, no "punching failure" occurred, and the pile head load continued to increase until the completion of loading. Source


Ishikawa K.,Kansai University | Ito A.,Kansai University | Ogura H.,JAPAN PILE Corporation | Shimohira Y.,General Building Research Corporation of Japan
AIJ Journal of Technology and Design | Year: 2013

The N -value of soil in the pressurized sand tank was necessary for comparing the results of loading test on model pile and actual pile. The relationships between relative density after pressurizing the soil, vertical loading pressure and the N -value were obtained from the standard penetration test in the tank. Using these relationships, the relationship between the bearing capacity of the model pile and the N -value was determined. By comparing this relationship with similar relationships obtained from the loading tests of actual pile, the results of model loading test using the tank and those of the standard penetration test were validated. Source


Yoshikawa N.,JAPAN PILE Corporation | Suzuki Y.,Kajima Technical Research Institute | Kobayashi K.,Japan Nuclear Energy Safety Organization | Kanai S.,Chiyoda Corporation | Abe Y.,Japanese Technical Association for Steel Pipe Piles and Sheet Piles
AIJ Journal of Technology and Design | Year: 2011

Based on past field test data on the horizontally loaded single piles, the authors have proposed a p-y model, which relates unit subgrade reaction force and pile displacement, for single piles. Particular attention was paid to evaluate the coefficient of horizontal subgrade reaction taking the pile diameter and the soil properties into account. The hyperbolic model presented in this paper shows good applicability to simulate the non-linear response of single piles subjected to horizontal loads regardless of the types of piles and soils, which can be useful for the advanced seismic design of piles. Source


Ishikawa K.,JAPAN PILE Corporation | Ito A.,Kansai University | Ogura H.,JAPAN PILE Corporation
Journal of Structural and Construction Engineering | Year: 2013

Vertical loading tests were performed on the enlarged grouted base of nodular pile using pressurized sand tank for studying the effects of strength and diameter of enlarged grouted base on the pile bearing capacity. In the tests the failure of the enlarged grouted base tended to be "compression failure" when the strength of the base was low, and tended to be "splitting failure" when the strength of the base was high. When the diameter of the enlarged grouted base was large, the failure tended to be "punching failure" and/or "local compression failure" by the nodes, and the bearing capacity came down when the failure occurred by the upper node. To ensure the bearing capacity of nodular pile with enlarged grouted base, the strength of the base must be heightened in proportion to its diameter. Source


Ishikawa K.,Kansai University | Ito A.,JAPAN PILE Corporation | Ogura H.,Kansai University | Nagai M.,Kansai University | Nagai M.,JAPAN PILE Corporation
Journal of Structural and Construction Engineering | Year: 2011

Vertical loading tests were performed on the enlarged grouted base of nodular pile using pressurized sand tank for studying the effects of strength of enlarged grouted base and the length between the pile tip and tip of enlarged grouted base on the pile bearing capacity. The main conclusions based on the studies are as follows. 1) When the tip length was zero and the strength of enlarged grouted base was greater than 10 N/mm2, the bearing capacity was equivalent to the case when the strength was 20 N/mm 2 until the settlement reached 10% of the pile diameter. 2) When the strength of the enlarged grouted base was 15 N/mm2, there was no effect of the tip length on the load-settlement curve. 3) For all cases, even when the enlarged grouted base failed, the bearing capacity continued to increase. Source

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