Centrifuge model testing for pile foundation reuse

Begaj, L; McNamara, A. M.

doi:10.1680/ijpmg.2011.11.4.166

Cited by 7 publications

(5 citation statements)

References 4 publications

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“…More recently, Karlsrud [25] compiled a database of large-scale single pile load tests which were conducted at various soft soil test sites. In most cases, the author documented increases in pile capacity after preloading similar to that noted by Begaj and McNamara [2]. In addition to preloading effects, Karlsrud [25] noted that pile reloading capacity continued to increase long after full consolidation was estimated to finish; this was attributed to additional ageing set-up.…”

Section: Introductionsupporting

confidence: 55%

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Numerical simulations of the reuse of piled raft foundations in clay

Sheil

2017

Acta Geotech.

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The development and growth of urban environments in recent years is requiring geotechnical engineers to consider foundation reuse as a more sustainable solution to inner city redevelopment. Two main phenomena associated with foundation reuse have been reported in the literature, namely 'preloading effects' and 'ageing effects'. The aim of this paper is to investigate the relative merits of these effects on the reusability of both piled and unpiled raft foundations in clay. Finite element analysis, in conjunction with an isotropic elasto-viscoplastic soil model, is employed for this purpose. The study is presented in two phases: (1) evaluation of preloading effects only by using a very low creep coefficient and (2) evaluation of combined preloading and creep effects. The variables considered in the parametric study include the number of piles, pile spacing, pile length, and soil type. Results show that both unpiled and piled rafts can exhibit significant capacity and stiffness increases upon reloading even for moderate levels of preload. Moreover, these increases are strongly dependent on the piled raft load sharing where unpiled raft and free-standing pile group capacity gains serve as upper and lower bounds, respectively, for that of a piled raft. This study underlines foundations reuse as an effective and sustainable solution for inner city redevelopment.

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Section: Introductionsupporting

confidence: 55%

“…Begaj and McNamara [2] utilised centrifuge modelling to investigate the influence of preloading on the load-displacement behaviour of single piles in Kaolin clay. These authors noted that the higher the level of preload, the higher the capacity of the pile upon reloading.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulations of the reuse of piled raft foundations in clay

Sheil

2017

Acta Geotech.

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“…Whilst the new permanent piles had not been loaded at the time of the test one pile, P103, was quite close to the solid test pile (1.86m away) and its potential influence should not be ignored. The presence of P103 seems unlikely to have had a detrimental effect on the performance of either of the test piles as it would have provided general stiffening to the ground in the vicinity of the piles and therefore increase their capacity (Begaj and McNamara, 2011). If any affect existed it could be expected to enhance the solid pile capacity more than the hollow pile because of its relative proximity.…”

Section: The Test Site and Ground Profilementioning

confidence: 99%

“…This problem is itself often compounded by a general reluctance to allow the existing piles to carry their full intended design load. In reality, pile capacity often increases with time (Wardle et al 1992, Powell and Butcher, 2003and Begaj and McNamara, 2011 although there may be problems to overcome such as the heave cracking that can occur when unreinforced piles are unloaded during demolition of a building.…”

Section: Introductionmentioning

confidence: 99%

A field trial of a reusable, hollow, cast-in-situ pile

McNamara¹,

Suckling²,

McKinley³

et al. 2014

Proceedings of the Institution of Civil Engineers - Geotechnica

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link Number of words in main text and tables:5138 words Number of figures: figures AbstractThis paper describes the concept and field testing of a 1200mm diameter x 30m deep hollow cast in situ rotary bored pile foundation. The aim of the foundation is to allow large diameter piles to be constructed using less concrete than in an equivalent conventional solid pile and with a view to allowing reuse at a later date. Reuse is made possible because the hollow core of the pile allows access for inspection after demolition of an existing structure. The new piles may also allow modification to enhance load capacity by augering through the base and extending their length. In addition, the piles are better suited than conventional piles for use as 'energy piles' to allow environmentally friendly heating and cooling. The geotechnical performance of the hollow test pile was comparable with a conventional solid pile constructed during the same trial. Details of construction are given including lessons learned.• A list of notations, defining all of the symbols used.•

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“…Mair (1979) developed a method for creating these homogenous samples for clay models by mixing kaolin powder with distilled water. Usual practice since then has been to prepare a slurry to a water content of 120% and place this slurry within a soil container known as a strongbox or strongtub (Grant 1998;McNamara 2001;Begaj 2009;Divall 2013;Le 2017). The slurry is subjected to a known stress history using hydraulic or pneumatic consolidation presses to arrive at a homogenous sample.…”

Section: Introductionmentioning

confidence: 99%