Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design
This paper presents a numerical study of 33 pile groups embedded in clay under vertical and inclined eccentric loads. Simplified modelling, based on elastic beams embedded in a soil continuum, is used to explore the soil-pile-cap response. This simple model allows rigorous treatment of the 3D founda...
| Main Authors: | , |
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| Format: | Journal article |
| Language: | English |
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Elsevier
2021
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| _version_ | 1797106596733517824 |
|---|---|
| author | Franza, A Sheil, B |
| author_facet | Franza, A Sheil, B |
| author_sort | Franza, A |
| collection | OXFORD |
| description | This paper presents a numerical study of 33 pile groups embedded in clay under vertical and inclined eccentric loads. Simplified modelling, based on elastic beams embedded in a soil continuum, is used to explore the soil-pile-cap response. This simple model allows rigorous treatment of the 3D foundation geometry and local soil plasticity, demonstrated through validation with 3D finite element analysis. The numerical results reveal that complex roto-translational displacements of the pile group are induced by eccentric or inclined loads, with highly nonlinear relationships when soil plasticity is considered. Interestingly, vertical eccentric loads mobilise the lateral soil resistance at large cap displacements. Thus, while existing t-z type models are shown to be adequate for serviceability predictions, they could provide overly-conservative estimates of the ultimate load capacity. Also, foundation internal forces can exceed allowable bending moments of reinforced concrete piles under multi-directional loads. For performance based design of pile groups under inclined eccentric actions, engineers should estimate the impact of soil yielding on both displacements and rotations of the cap, to satisfy limit state requirements. Dimensionless charts are presented, which describe the reduction in vertical capacity, for a prescribed cap displacement, as a function of load eccentricity and inclination. |
| first_indexed | 2024-03-07T07:04:43Z |
| format | Journal article |
| id | oxford-uuid:69346681-2c11-4379-9ab8-3ebfd196586a |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T07:04:43Z |
| publishDate | 2021 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | oxford-uuid:69346681-2c11-4379-9ab8-3ebfd196586a2022-04-22T10:52:21ZPile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based designJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:69346681-2c11-4379-9ab8-3ebfd196586aEnglishSymplectic ElementsElsevier2021Franza, ASheil, BThis paper presents a numerical study of 33 pile groups embedded in clay under vertical and inclined eccentric loads. Simplified modelling, based on elastic beams embedded in a soil continuum, is used to explore the soil-pile-cap response. This simple model allows rigorous treatment of the 3D foundation geometry and local soil plasticity, demonstrated through validation with 3D finite element analysis. The numerical results reveal that complex roto-translational displacements of the pile group are induced by eccentric or inclined loads, with highly nonlinear relationships when soil plasticity is considered. Interestingly, vertical eccentric loads mobilise the lateral soil resistance at large cap displacements. Thus, while existing t-z type models are shown to be adequate for serviceability predictions, they could provide overly-conservative estimates of the ultimate load capacity. Also, foundation internal forces can exceed allowable bending moments of reinforced concrete piles under multi-directional loads. For performance based design of pile groups under inclined eccentric actions, engineers should estimate the impact of soil yielding on both displacements and rotations of the cap, to satisfy limit state requirements. Dimensionless charts are presented, which describe the reduction in vertical capacity, for a prescribed cap displacement, as a function of load eccentricity and inclination. |
| spellingShingle | Franza, A Sheil, B Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design |
| title | Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design |
| title_full | Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design |
| title_fullStr | Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design |
| title_full_unstemmed | Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design |
| title_short | Pile groups under vertical and inclined eccentric loads: Elastoplastic modelling for performance based design |
| title_sort | pile groups under vertical and inclined eccentric loads elastoplastic modelling for performance based design |
| work_keys_str_mv | AT franzaa pilegroupsunderverticalandinclinedeccentricloadselastoplasticmodellingforperformancebaseddesign AT sheilb pilegroupsunderverticalandinclinedeccentricloadselastoplasticmodellingforperformancebaseddesign |