• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.17-19
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• 2010

This paper describes the possibility of the raft thickness reduction for mega foundations system of super high-rise buildings through a case study on domestic and foreign super high-rise buildings. In case of super high-rise buildings, the size of foundations, especially raft becomes wider and deeper because of heavy upper load. It is difficult to pour concrete of this kind of mega foundation, and cracks by hydration heat could happen. Therefore, there are several ways to reduce the raft thickness of mega foundations. Piled-raft could be the one because moment and shear load that the raft subjects on by soil reaction are lower. The effect of the piled-raft foundation on the raft thickness reduction could be confirmed by comparison of super high-rise buildings with pile, piled-raft and mat foundation. Furthermore, it was showed that the raft thickness could be more reduced by locating piles right under the vertical members of super structures.

• Proceedings of the Korean Geotechical Society Conference
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• 2007.09a
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• pp.55-77
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• 2007

Currently a large number of high rise building projects are under plan and a mega foundation system to support this high load with safety is requiring. The foundation of a highrise building is displaced by the building load, which influence the behavior of a super structure in reverse. In this aspect, the structural interaction analysis between a foundation and a super structure is necessary. In this study, the relationship of a superstructure of building and a foundation has been reviewed, considering the tendency of design from a capacity driven design to a performance design. Two different case studies have been introduced to help understand this relationship in more specific, the first case is the high rise building founded on a mat system on rock and the second is that on large diameter bored piles on soft ground condition.

• International Journal of High-Rise Buildings
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• v.4 no.4
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• pp.261-270
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• 2015

Hong Kong is a renowned small city with densely placed skyscrapers. It is no surprise that heavy duty or even mega foundations are built over the years to support these structures. To cope with the fast construction pace, several heavy deep foundation types have been widely adopted with some prescribed design rules. This Paper has selected two commonly adopted but distinctive foundation types, namely large diameter bored piles and percussive steel H-piles to illustrate the special design and construction considerations related to these pile types in related to local context. The supervision requirement in related to foundation works for which again may be unique in Hong Kong will also be highlighted. A case history is also discussed in the later part of the Paper to illustrate the application of one of these foundations and to highlight the importance of considering foundation design and basement excavation method in a holistic manner.

• International Journal of High-Rise Buildings
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• v.4 no.4
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• pp.241-247
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• 2015

In this study, an approximate computer-based method was developed to analyze the behavior of raft and piled raft foundations. Special attention is given to the improved analytical method proposed by considering raft flexibility and soil nonlinearity. The overall objective of this study is to focus on the application of a simplified analysis method for predicting the behavior of sub-structures. Through the comparative studies, it is found that the computer programs (YS-MAT and YSPR), developed in this study, is in agreement with the general trends observed by field measurements. Therefore, YS-MAT (Yonsei-Mat) and YSPR (Yonsei Piled Raft) can be effectively used for the preliminary design of a raft or a piled raft foundation for high-rise buildings.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.559-568
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• 2010

Recently, because of mega foundations and grand bridges, the foundations require significant bearing capacity. In this study, bearing capacity of high strength steel pipe pile with an extended head (HSP) is calculated on the basis of domestic criteria and Japanese criteria. And bearing capacity of HSP is investigated based on 3 field tests. In comparison with the results of analysis and tests, it is shown that the field test results are bigger than analysis results. Therefore, it is proposed to estimate bearing capacity of HSP.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.122-130
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• 2010

In recent days, the foundations of huge structures in general and mega foundations of grand bridges in particular are required in geotechnical engineering. However, previous design method based on virtual fixed point theory cannot adequately predict Pile-Bent structure‘s physical behavior. Therefore, this paper describes a new analysis and design of Pile-Bent structure for grand bridges. A detailed analysis was performed for column-pile interactions using FB-Pier program and Midas program. As a result, the behavior of a column-pile is estimated and highlighted. Moreover, based on this study, it is found that the minimum reinforcement ratio(=0.4%) is applicable for plastic behavior of columns.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.420-429
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• 2009

This study concerns bearing capacity of shallow and deep foundations on jointed rock mass. The main focus of this research lies on getting insight into the applicability of bearing capacity estimation methods developed by other researchers. First, an extensive literature review was performed on previous studies concerning bearing capacity of foundation on jointed rock mass. Second, a parametric study on a number of jointed rock conditions using the finite-element analysis. The results of the analysis were then compared with those computed by the bearing capacity estimation method.

• Journal of the Korean Geotechnical Society
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• v.26 no.8
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• pp.39-47
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• 2010

In recent days, the foundations of huge structures in general and mega foundations of grand bridges and high-rise buildings in particular are required in geotechnical engineering. This study described 3 dimensional behavior of mat foundation on soft rock based on a numerical study using 3D finite element method. A series of numerical analyses were performed for various soil conditions and mat rigidities under vertical loading. Based on the results of the parametric study, it is shown that the prediction of the settlement, cross sectional tensile stress and bending moments in the mat is overestimated in the analysis without considering interface behavior in comparison with the analysis considering interface between mat and rock mass.

• International Journal of High-Rise Buildings
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• v.4 no.3
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• pp.219-226
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• 2015

By the end of 2014, the number of completed and under-construction supertall buildings above 250 meters in China reached 90 and 129, respectively. China has become one of the centers of supertall buildings in the world. Supertall buildings in China are getting taller, more slender, and more complex. The structural design of these buildings focuses on the efficiency of lateral resisting systems and the application of energy dissipation. Furthermore, the research, design, and construction of high-performance materials, pile foundations, and mega-members have made a lot of progress. Meanwhile, more and more challenges are presented, such as the improvement of structural system efficiency, the further understanding of failure models, the definition of design criteria, the application of high-performance materials, and construction monitoring. Thus, local structural engineers are playing a more important role in the design of supertall buildings.

• Journal of the Korean GEO-environmental Society
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• v.10 no.3
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• pp.29-36
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• 2009

In this paper, a case of a high-rise building supported by a large-diameter drilled shaft socketed in a weathered ground has been studied. The design case of pile foundation presented in this paper could be a representative example of execution of pile design through three(3) design stages of "preliminary design-proof test-supplementary design". As proof test, two(2) BDH PLT (Bi-directional High Pressure Pile Load Test) were performed at the early construction stage. By following the design process of this way, the economic pile design could be carried out and a large amount of construction cost saving could be realized.