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1

Seismic response of pile-supported structure considering nonlinearity of superstructure and pile, and liquefaction of surrounding ground; Shuhen jiban no ekijoka oyobi kui no hisenkeisei wo koryoshita kui shiji tatemono no jishin oto kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Recent earthquake disasters have revealed the importance of countermeasures against soil Liquefaction in seismic design. In particular, the 1995 Hyogoken Nanbu earthquake caused several types of severe damages to pile foundations. This paper describes an analysis method for soil liquefaction using simple parameters such as SPT-N values and seismic response analyses for the pile-supported structure to consider soil-structure interaction effects and soil non-linearity using a modified Penzien model. It is important to find a way to determine the region of surrounding soil whose behavior is identical to that of piles. This paper adopts the thin layer element method to systematically determine the volume of the surrounding soil. The responses of pile-supported structure are similar, whether soil liquefaction and nonlinearity of pile are considered or not. However, the bending moment of pile become large as to soil liquefaction, and small as to nonlinearity of pile. (author)

2000-01-10

2

Trial design of pile foundation by limit state design; Genkai jotai sekkeiho ni yoru kui kiso no shisekkeirei  

Energy Technology Data Exchange (ETDEWEB)

This paper introduces the summary of design guideline (draft) for the limit state design method for foundation structures, and examples of calculations on pile foundations. The limit states were set using the load to transformation curves, and the limit state No. 3 in particular assumed a large earthquake, a state that a foundation is fatally damaged because of rarely acting loads that lead to generation of displacement and loss of stability and functions. Ground survey coefficient, ground resistance coefficient, and ground property coefficient were defined especially as the safety coefficients. With respect to the displacement in the limit state No. 3, a restriction value was set for the plasticity of the foundation. Loads were given considerations of combination of permanent load, variation load, and accidental load, each having been set with a load coefficient. It was decided regarding earthquakes to discuss strength and toughness of members, displacement of structures, and ...

1994-09-01

3

Stability analysis based on expanded displacement method for pile foundations; Kakucho hen`iho ni yoru kui kiso no jitsuyo antei keisanho ni tsuite  

Energy Technology Data Exchange (ETDEWEB)

Method is proposed for expanding the pile foundation elastic analysis method (displacement method) to cover a larger displacement region, and its appropriateness is verified by a field test. In this report, stability calculation is discussed in which the present displacement method is expanded by assuming an equivalent plastic hinge on the pile head and by replacing the soil spring in the large displacement region with an equivalent linear elastic spring. A static horizontal loading test is conducted for a foundation using a real pile, which is an application of this method. On the assumption that a hinge is generated on the pile head, the pile spring constant of the current displacement method is replaced with a value that takes into consideration the plastic hinge region, and this enables the analysis of pile behavior even after breakdown. This method is applied to the result of a loading test using a real foundation, and it is found that it can roughly simulate the real relationship ...

1997-06-21

4

Proposition for execution control of bearing stratum in bored precast pile method. Umekomi kui koho ni okeru shijiso kakunin no tame no seko kanri hoho no teian  

Energy Technology Data Exchange (ETDEWEB)

As a parameter for execution control of confirming a bearing stratum, which is most important in a bored precast pile method, discussions were made on the relativity between the product AT'' of a load current value A'' in an electric motor driving an auger used to drill pit holes with an excavation time T'' and a value N,'' a result of the standard penetration test of the ground. As a result, although the relativity of the N'' value has some variance in the ground of diluvial clay, they correspond well to each other in other kinds of ground. In pile bearing strata in particular, they correspond very well to each other regardless of soil textures of the ground, proving clearly that the AT'' value can be used as an effective parameter for confirmation of and penetration into the bearing stratum. Therefore, tips of all the piles used in one construction site can be driven to about ...

1991-07-25

5

How to apply the uncertainties in estimating the vertical resistance of piles to limit state design; Kui no shijiryoku suitei ni okeru jikakujitsusei to genkai jotai sekkeiho eno tekiyo  

Energy Technology Data Exchange (ETDEWEB)

This paper describes effects of methods to calculate and analyze bearing capacities and transformation of pile foundations in the limit state design method. Different pile bearing capacity estimating expressions including criteria used in other countries were applied to the case of steel piles driven into the `diatomaceous mudstone ground` in Noto Peninsula, Ishikawa Prefecture where detailed ground and soil surveys have been made, and the case of piles driven in place into the `sandy and clayish soil alternating ground layers` at the Tennoji area in Osaka Prefecture. The results were compared with those of static loading tests. As a result, the estimated bearing capacity limit was found to agree relatively well with the measured values where uniaxial compression strength was used according to the reference architectural formula. The estimated bearing capacity limit using the N-value as the soil constant has underestimated the bearing capacity irrespective of whichever methods in the ...

1994-09-01

6

Elasto-plastic analysis of settlement of pile foundations. Part 2. ; Prediction of immediate settlement of building. Kui kiso no dansosei chinka kaiseki. 2. ; Kenchikubutsu no sokuji chinka yosoku hoho  

Energy Technology Data Exchange (ETDEWEB)

When the foundations of the building are designed and worked, the prediction calculation of immediate settlement of the building exercised practically is to calculate assuming the earth is a linear elastic body, but the actual stress-strain relationship of the earth is nonlinear and rigidity of the earth becomes lower as strain (or stress) increases. Hence in order to grasp the actual settling behavior of the earth, it is necessary to elucidate the nonlinear relationship between stress and strain. In this article, a prediction method of building settlement is introduced which uses an analytical technique of the multi-layered earth by the linear elasticity theory and takes into consideration strain dependency of rigidity of the earth. Part of the conclusion is as follows which has been obtained by studying the settling behaviors observed in examples of vertical loading tests of the pile foundations and the elasto-plastic settlement analytical method of the pile foundations; the settling ...

1992-12-25

7

Development of cast-in-place concrete pile installation technique for application in the presence of artesian water; Hiatsu chikasui kasho ni okeru bashouchi kui sekoho no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

When a rotary excavator is operated at locations where there is artesian water, the aquiclude is fractured under pressure of the artesian water upon the penetration of the pile tip through the aquiclude. Since the equipment is provided with a gap for the reduction of friction between the casing and the excavation face, soil and sand near the pile tip burst forth out of the ground together with underground water through the casing or along the outer circumference of the casing. The newly contrived method introduced here is a double pipe process, in which a large casing (2.0m in diameter) is driven until it lands on the aquiclude, water is injected into the casing for the creation of equilibrium between the artesian head and the head in the casing, and finally a casing as large as the pile (1m in diameter) to be installed is used for the excavation of the artesian water section. Since February, 1996, 4 systems/16 legs have been operated for the installation of 96 piles using this ...

1998-11-05

8

Consolidation settlement analysis of pile foundations; Kui kiso no atsumitsu chinka kaiseki  

Energy Technology Data Exchange (ETDEWEB)

Deformation of the ground can be considered as a sum of volume deformation and shear deformation. At circumferential ground of pile axis, simple shear type of shear deformation becomes main factor of settlement. As shear forces with reverse direction are overlapped at parallel face for pile around face of the ground between the piles, the shear deformation is relaxed. At deeper place from top of the pile, volume deformation becomes larger and component of shear deformation approaches to a pure shear type. In case of the land surface loading type consolidation settlement calculation, a method adopting one dimensional consolidation calculating method using only vertical component within stress obtained by elasticity theory even when investigating multi dimensionally is used widely. In Japanese design standards, the method calculating the consolidation settlement by presuming imaginary loading face for land surface is widely adopted. In case of abrasion pile, the imaginary loading face is ...

1997-02-01

9

Proposal concerning calculation method of bearing power of cast-in-place piles in gravel layer; Rekiso ni okeru basho uchi kui no shijiryoku santeiho ni kansuru ichiteian  

Energy Technology Data Exchange (ETDEWEB)

The Minami-Iwaki trunk line now under construction by Tokyo Electric Power Company is an UHV transmission line which covers 130km from the central region of the Abukuma highlands, Fukushima Prefecture, through the northern ridge of the Kanto Plain to Imaichi City, Tochigi Prefecture and has 235 steel towers. About 30% of the ground along the above route is mainly layers of sand and gravel. Accordingly it has become urgent to design rationally the pile foundations in the sand and gravel layers. Hence the company has studied an estimation method of the ultimate bearing power of cast-in-place piles penetrating the sand and gravel layers and the displacement of pile heads. In this report, the result of the above study is described. The company has so far used the equations in accordance to the Meyerhof equations for the estimations of the ultimate bearing power and this time, this equations have been examined for its application to the sand and gravel layers, and for designing the steel ...

1995-11-05

10

Design and construction of 125,000kl industrial water tank foundations for Tachibanawan power plant. Deformation in large pile foundations on inclined rockbed and evaluation thereof; Tachibanawan hatsudensho 125,000 kl kogyoyosui tank kiso no sekkei to seko. Keisha kiso ganbanjo no ogata kui kiso no henkei tokusei to hyoka  

Energy Technology Data Exchange (ETDEWEB)

The two tank (125,000kl each) foundations under construction are as large as 85m in diameter, and the north-side tank is to be placed over a sharper slope. The tanks are greatly different in their height from the rockbed since they are to be placed at the same level. For reduction in construction cost and time, a pile foundation design is chosen as the basic concept for foundation construction. After an overall evaluation of stability upon exposure to seismic torsion and of the deformation characteristics of piles and concrete slabs, a total pile foundation design with rock debris replaced with crushed rock is determined to be the design to be adopted. Since the piles to be driven in are greatly different in length, error in the pile supporting force will be too grave under the conventional pile landing control system. Therefore, a high-accuracy pile landing control system is employed, established after a rapid load test in addition to the dynamic load test for the confirmation of the ...

1998-09-05