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postgraduate thesis: Behavior of a piled cap foundation under a vertical loading
Title | Behavior of a piled cap foundation under a vertical loading |
---|---|
Authors | |
Advisors | Advisor(s):Tham, LG |
Issue Date | 2011 |
Publisher | The University of Hong Kong (Pokfulam, Hong Kong) |
Citation | Yu, Z. [余振雄]. (2011). Behavior of a piled cap foundation under a vertical loading = Chui zhi he zai xia zhuang fa di ji de ji li. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4784986 |
Abstract | Hong Kong is a small city with a dense population. Due to limited land resources
and dense population, skyscrapers are built to meet the commercial and residential
needs. To fulfill the functional requirements, the superstructure is usually
supported by piles through a thick cap. A bored pile foundation is one of the most
common deep foundation systems with a high capacity adopted in Hong Kong.
Most of those piles are founded on Grade III or better rock. However, as lack of
field experience and high quality database, the behavior of such pile foundation
system is still unclear. These bored piles are designed as the end bearing piles. In
addition, the load distribution among the piles and the load shared by the pile cap
are also not properly addressed in the local design. In order to properly address the
above-mentioned issues related to the design of pile foundation, in particular for
large diameter bored piles, a comprehensive field study was launched.
Furthermore, the numerical simulations were also carried out.
A comprehensive field study was carried out on the behavior of a building
supported by large diameter bored piles. The building (40-storey public housing)
is Y-shaped with three wings (Wing A, Wing B, and Wing C) and a central core
(Central Core). The superstructure is resting on a Y-shaped foundation cap (2.3m
in thickness) which is supported by 18 bored piles (2.2m in diameter). The piles
terminated at Grade III or better rocks. The field test results indicated that the pile
group took up most of the applied load, while the cap had an insignificant
contribution to the capacity of the foundation system. The axial force in the pile
increased from the outer edge to the inner area of the cap. The shaft resistances
mobilized in the soil layer and the rock layer were significant. As a result, the
axial force reduced to a not significant level at the toe.
The finite element model could generally reflect the bored pile deformation and
the load distribution along the pile. The numerical simulation results could
generally reveal the load distribution among the piles. Based on the numerical
analyses, the load distribution among the piles was strongly dependent on the cap
stiffness. Moreover, when some pile stiffness reduced, the applied load will
redistribute among the piles. More loads will transfer to the nearby stiff piles. The
effected region of redistribution in axial force increased with the cap stiffness. |
Degree | Master of Philosophy |
Subject | Piling (Civil engineering) Foundations. |
Dept/Program | Civil Engineering |
Persistent Identifier | http://hdl.handle.net/10722/174544 |
HKU Library Item ID | b4784986 |
DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Tham, LG | - |
dc.contributor.author | Yu, Zhenxiong | - |
dc.contributor.author | 余振雄 | - |
dc.date.issued | 2011 | - |
dc.identifier.citation | Yu, Z. [余振雄]. (2011). Behavior of a piled cap foundation under a vertical loading = Chui zhi he zai xia zhuang fa di ji de ji li. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4784986 | - |
dc.identifier.uri | http://hdl.handle.net/10722/174544 | - |
dc.description.abstract | Hong Kong is a small city with a dense population. Due to limited land resources and dense population, skyscrapers are built to meet the commercial and residential needs. To fulfill the functional requirements, the superstructure is usually supported by piles through a thick cap. A bored pile foundation is one of the most common deep foundation systems with a high capacity adopted in Hong Kong. Most of those piles are founded on Grade III or better rock. However, as lack of field experience and high quality database, the behavior of such pile foundation system is still unclear. These bored piles are designed as the end bearing piles. In addition, the load distribution among the piles and the load shared by the pile cap are also not properly addressed in the local design. In order to properly address the above-mentioned issues related to the design of pile foundation, in particular for large diameter bored piles, a comprehensive field study was launched. Furthermore, the numerical simulations were also carried out. A comprehensive field study was carried out on the behavior of a building supported by large diameter bored piles. The building (40-storey public housing) is Y-shaped with three wings (Wing A, Wing B, and Wing C) and a central core (Central Core). The superstructure is resting on a Y-shaped foundation cap (2.3m in thickness) which is supported by 18 bored piles (2.2m in diameter). The piles terminated at Grade III or better rocks. The field test results indicated that the pile group took up most of the applied load, while the cap had an insignificant contribution to the capacity of the foundation system. The axial force in the pile increased from the outer edge to the inner area of the cap. The shaft resistances mobilized in the soil layer and the rock layer were significant. As a result, the axial force reduced to a not significant level at the toe. The finite element model could generally reflect the bored pile deformation and the load distribution along the pile. The numerical simulation results could generally reveal the load distribution among the piles. Based on the numerical analyses, the load distribution among the piles was strongly dependent on the cap stiffness. Moreover, when some pile stiffness reduced, the applied load will redistribute among the piles. More loads will transfer to the nearby stiff piles. The effected region of redistribution in axial force increased with the cap stiffness. | - |
dc.language | eng | - |
dc.publisher | The University of Hong Kong (Pokfulam, Hong Kong) | - |
dc.relation.ispartof | HKU Theses Online (HKUTO) | - |
dc.rights | The author retains all proprietary rights, (such as patent rights) and the right to use in future works. | - |
dc.rights | This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. | - |
dc.source.uri | http://hub.hku.hk/bib/B47849861 | - |
dc.subject.lcsh | Piling (Civil engineering) | - |
dc.subject.lcsh | Foundations. | - |
dc.title | Behavior of a piled cap foundation under a vertical loading | - |
dc.type | PG_Thesis | - |
dc.identifier.hkul | b4784986 | - |
dc.description.thesisname | Master of Philosophy | - |
dc.description.thesislevel | Master | - |
dc.description.thesisdiscipline | Civil Engineering | - |
dc.description.nature | published_or_final_version | - |
dc.identifier.doi | 10.5353/th_b4784986 | - |
dc.date.hkucongregation | 2012 | - |
dc.identifier.mmsid | 991033487169703414 | - |