An investigation about seismic behavior of piled raft foundation for oil storage tanks using centrifuge modelling

Sahraeian, S. Mohammad Sadegh; Takemura, Jiro; Seki, Sakae

doi:10.1016/j.soildyn.2017.10.010

Cited by 28 publications

(6 citation statements)

References 20 publications

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“…The strategic location of piles plays a key role in improving the load-bearing capacity of the raft and also serves to minimize the total and differential settlement. Moreover, due to recent technological advancements, piled-rafts are now not only limited to high-rise structures but can also find their application in bridges, thermal power plants, offshore structures, residential buildings, and oil storage tanks [14,15]. Various approaches to piled-raft analysis have been briefly reviewed in the subsequent section.…”

Section: Fig 1 Interaction Mechanism In Piled-raftsmentioning

confidence: 99%

Load sharing behaviour in piled-raft foundations over sand and clay: An experimental investigation

Pandey,

Mourya,

Patel

et al. 2024

Res. Eng. Struct. Mat.

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Piled-raft foundations have gained increasing popularity in the past few decades, providing a viable alternative to traditional raft and pile foundations. Despite this, designers are reluctant to apply them frequently in practice due to their complex behaviour and the lack of well-defined guidelines specific to piled-raft foundations. Previous studies have demonstrated that piled-rafts are more effective in reducing settlement and can sustain heavier loads from superstructures. Experimental investigations have been conducted in the present study to ascertain the load-sharing behaviour in piled-raft foundations under vertical loading. Since experimental research on piled-rafts, especially over clay, is quite sparse, small-scale lab tests were conducted on piled-rafts over both sand and clay. Experimental comparisons of unpiled rafts and rafts with piles have been established for a better understanding of the individual and collective response of piles and rafts. Moreover, the effects of a few geometric parameters on the load-bearing capacity of the foundation have been observed. The results showed a significant contribution of the raft to load sharing in piled-raft foundations. It was also observed that the individual load-bearing capacities of the raft and the piles, when summed together, differ from that of the piled-raft foundation due to the interactions between the soil and the foundation components. Observations also supported the fact that increasing the length and number of piles enhances the load-bearing capacity of the foundation. The load-sharing ratio and load improvement ratio increase with the number of piles. Eventually, it can be concluded that piled-rafts are better at minimizing settlement and simultaneously carrying heavier loads.

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Section: Fig 1 Interaction Mechanism In Piled-raftsmentioning

confidence: 99%

Load sharing behaviour in piled-raft foundations over sand and clay: An experimental investigation

Pandey,

Mourya,

Patel

et al. 2024

Res. Eng. Struct. Mat.

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“…It was also found that the (PR) foundation's ultimate load capacity is inadequate to the value of the raft's ultimate capacity plus all the piles. Sahraeian (2018) [8] performed a set of centrifuge model's experiments to analyze the mechanical behavior of oil tanks placed on a P-R foundation system on Saturated liquefied sand and dry, non-liquefied sand. Two forms of foundations were tested; a slab foundation (SF) and a PRF.…”

Section: Previous Studiesmentioning

confidence: 99%

Effect of Pile's Number on the Behavior of Piled Raft Foundation

Hadi¹,

Waheed²,

Fattah³

2021

ETJ

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This paper introduces an experimental research on the behavior of the piled raft foundation (PRF) in sand of two states (loose and medium sand). A small model has been tested in a soil container and the vertical load was applied to the foundation through a pneumatic jack. The settlement of the foundation was measured using a displacement transducer; three sensors were attached to the pile heads to measure the axial load borne in a group by each pile by the Arduino data logger. The laboratory experiments were carried out on models of (1 pile), ( 1x2), ( 1x3), ( 2x3), (3 x3), (3 piles triangular), (4 piles diamond), (5 piles), and (9 pile circle), as well as to tests on an unpiled raft. Test variables were pile length, number of piles, and sand density. It is noticed that when the piles increased to nine piles in the group, the bearing capacity increased by 40%. The effect starts to increase when one pile is just placed under the raft as the bearing capacity of the piled raft increased by 3% and 7% when the pile length is 15D and, 20D, respectively. The reduction in the settlement is also observed to be smaller and no economic advantage is achieved with more increase in the number of piles. If the number of piles reaches (6) piles, the influence of the piled raft on settlement reduction disappears.

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“…Imamura et al (2010) performed dynamic centrifuge tests to compare the mechanical behavior of an oil tank supported by piled raft foundation and slab foundation on liquefiable sand. Sahraeian et al (2017Sahraeian et al ( , 2018 investigated the mechanical behavior of oil tank supported by piled raft foundation on the liquefiable saturated sand and dry sand through centrifuge model tests. In these studies, the performance of piled raft in liquefaction condition was well investigated and the dynamic and permanent rotation, settlement, pile forces were expressed.…”

Section: Introductionmentioning

confidence: 99%

Seismic performance of end-bearing piled raft with countermeasure strategy against liquefaction using centrifuge model tests

Fallahzadeh

Haddad

Jafarian

et al. 2019

Bull Earthquake Eng

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This paper presents the results of centrifuge model tests conducted on piled raft foundations in liquefiable soils to investigate the performance of drainage techniques as a liquefaction countermeasure method. Two series of centrifuge tests were conducted on 2 × 2 end-bearing piled raft foundations with and without drainage wells in multilayer soil deposits. The results indicate that the drainage well systems significantly reduce the foundation settlement, the excess pore water pressure ratio, and the time of dissipation under seismic loading by providing shortened water flow paths. Variations of the acceleration response, bending moment, and axial force of the piled raft are shown to be dependent on the type of surface layer. In Test-1-E with the liquefiable surface layer, the acceleration response, bending moment, and axial force of the piled raft with drainage systems were significantly larger than those observed in the piled raft without drainage systems during shaking. In contrary, in Test-2-E including a non-liquefiable surface layer, bending moment and axial force of piled raft in the absence of drainage wells were larger than those of the piled raft system with drainage wells. However, the acceleration response of raft in both systems was almost the same during shaking. The recorded data of the piled raft systems with/without vertical drains and the surface gravel layer (as a horizontal drainage system) are compared in details.

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An investigation about seismic behavior of piled raft foundation for oil storage tanks using centrifuge modelling

Cited by 28 publications

References 20 publications

Load sharing behaviour in piled-raft foundations over sand and clay: An experimental investigation

Load sharing behaviour in piled-raft foundations over sand and clay: An experimental investigation

Effect of Pile's Number on the Behavior of Piled Raft Foundation

Seismic performance of end-bearing piled raft with countermeasure strategy against liquefaction using centrifuge model tests

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