Piled raft foundations: design and applications

Poulos, Harry G.

doi:10.1680/geot.2001.51.2.95

Cited by 229 publications

(127 citation statements)

References 19 publications

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“…These spring stiffness values primarily depend upon soil shear modulus which is an intrinsic property of soil. However, a validation pertaining to overall pile group raft -soil stiffness has been conducted through overall stiffness of pile group as suggested by Poulos (2001). It is observed that overall lateral stiffness of piled raft obtained from the present model is in good agreement with various empirical and analytical methods (e.g.…”

Section: Idealization Of Pile Raft-soil Systemsupporting

confidence: 54%

Seismic Response of Soil-Pile Raft-Structure System

Saha

Dutta

Haldar

2015

Journal of Civil Engineering and Management

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Abstract. This paper presents an initial effort to investigate seismic response of soil-pile raft-structure system considering soil-structure interaction effect. In general, structure and piled raft under seismic load are designed considering fixed base condition. However, soil flexibility may result significant changes in the response of soil-pile raft-structure system. The study considers one storey system consisting of a mass in the form of a rigid floor slab supported by four columns. The piles are modelled by beam-column element supported by laterally distributed springs and dampers. This simple model used in present study is adequately tuned to exhibit reasonably accurate dynamic characteristics while compared to the existing well accepted methodologies. The study shows that soil-structure interaction leads to considerable lengthening of period though the lateral shear in columns are not significantly changed. However, the shear in piles is significantly increased due to SSI effect as inertia of the considerable foundation mass contributes to this increase in shear of pile. Thus, neglecting SSI may lead to unsafe seismic design of piles. A parametric study encompassing feasible variations of parameters is made under spectrum consistent ground motion. Effect of uncertainty in the soil subgrade modulus on the pile and column response variability is also studied.

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Section: Idealization Of Pile Raft-soil Systemsupporting

confidence: 54%

Seismic Response of Soil-Pile Raft-Structure System

Saha

Dutta

Haldar

2015

Journal of Civil Engineering and Management

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“…The ultimate bearing capacity (q ult ) of a rigid column-reinforced composite foundation can be estimated using the method proposed by Poulos (2001) for a piled raft foundation, which is the lesser of the following two load capacities: (a) the sum of the load capacities of the raft and all the rigid columns and (b) the sum of the load capacities of the equivalent pier and the raft outside the periphery of the pier.…”

Section: Rigid Columnsmentioning

confidence: 99%

“…Horikoshi and Randolph (1999) and Poulos (2001) proposed simplified design methods to calculate the settlement of piled rafts, which are both based on pile-raft interaction. Horikoshi and Randolph (1999) used the equivalent pier concept for the piled raft method, as shown in Figure 11.…”

Section: Rigid Columnsmentioning

confidence: 99%

Recent research and development of ground column technologies

Han

2015

Proceedings of the Institution of Civil Engineers - Ground Impr

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In recent years, ground columns, such as vibro-concrete columns and geosynthetic-reinforced stone columns, have been increasingly used to support superstructures and embankments when they are constructed on soft foundations. Several new column technologies have emerged, including different shapes of concrete columns and composite columns. The column technologies have also been combined with other technologies to create more effective and/or economic solutions. However, the composite columns and the combined technologies have presented complicated geotechnical problems in design and construction. This paper summarises different types of column technologies and their functions, installation and applications, addresses design issues, and reviews recent research and development related to the column technologies to improve soft foundations, including failure modes, load transfer mechanisms, bearing capacity, settlement, consolidation and stability. Recent research has indicated that lateral deformation and yielding of columns should be considered in a unit cell model for the analyses of load transfer, deformation and consolidation. Several theoretical solutions have been proposed for the rate of consolidation of column-reinforced soft foundations. Different failure modes should be evaluated for the stability of column-supported embankments. Limit equilibrium methods based on shear failure overestimate the factors of safety of embankments on rigid or semi-rigid columns in soft soil.

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“…Such a task of the floor plate design consists of several components: the pile stiffness calculation, pile layout, selection of the floor plate thickness, reinforcement type and eligibility of calculations of floor plate settlements (Samofalov et al 2015;Basile 2015;Poulos 2001). According to the results of the numerical analysis, the existence of the raft does not affect the vertical stiffness of the pile head, if loadings less than the allowable load.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Pile Stiffness on the Ground Slab Behaviour

Urbonas

Sližytė

Mackevičius

2016

Journal of Civil Engineering and Management

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Abstract. Just as other structural elements, ground slabs are an important unit of a building. It is especially true in the case of buildings, such as logistic centres, for which the primary purpose is storage of various goods. In this kind of buildings, floor slabs usually have high loads. For buildings where truck lifts are used, there are special requirements for flatness tolerance across and along the driving track of truck lifts. Therefore, the floor settlement differences in selected distances are limited. In localities where the soils under the floor slab are weak, they should be replaced or compacted. If these solutions are not possible or economically inappropriate, the slabs have to be supported on piles that must be based on strong deep soils. During the design process, it is very important to assign a proper value of rigidity of the piles. Pile stiffness has an enormous influence on the settlement of the slab as well as on the reinforcement intensity of the slab or even on the slab thickness. This paper presents the methodology for the evaluation of pile stiffness. In addition, it provides recommendations for the calculation of the floor slab on the piles. Calculations and obtained results confirmed the importance of certain design stages.

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Piled raft foundations: design and applications

Cited by 229 publications

References 19 publications

Seismic Response of Soil-Pile Raft-Structure System

Seismic Response of Soil-Pile Raft-Structure System

Recent research and development of ground column technologies

Influence of the Pile Stiffness on the Ground Slab Behaviour

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