• 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.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.207-215
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• 2005

This paper presents a case history of a geosynthetics-reinforced segmental retaining wall, which collapsed during a sever rainfall immediately after the completion of the wall construction. In an attempt to identify possible causes for the collapse, a comprehensive investigation was carried out including physical and strength tests on the backfill, stability analyses on the as-built design based on the current design approaches, and slope stability analyses with pore pressure consideration. The investigation revealed that the inappropriate as-built design and the bad-quality backfill were mainly responsible for the collapse. This paper describes the site condition including wall design, details of the results of investigation and finally, lessons learned. Practical significance of the findings from this study is also discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.1147-1153
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• 2009

The failure modes of rock anchors subjected to tension can be defined as follows: tensile failure of tendon, shear failure on tendon-grout interface, shear failure on grout-rock interface and tensile failure of rock. This study proposes a design method to induce the rock anchor systems to avoid the brittle failure by ensuring the minimum embedded length of rock anchors. Pull-out test results of full-scale rock anchors show that the proposed method is effective in predicting the design conditions expecting the ductile tendon failure.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1057-1064
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• 2009

Since the global warming causes debris flow damage has increased in Kangwon Area, Sediment control dam have increasingly founded to protect the damage. In spite of the realities design methods are well not established to determine type of the dam, design parameters and maintenance. Through comparison for design methods to sediment control dam in Korea, it raised some points to improve to correspond with realities. In addition, it pointed that some issues for the sediment control dams in Kangwon Area. Those are shown that unclear positions of the dams, unremoval of sediment, occurrence of seepage under the dams and uninstallation of roads to remove sediment. In addition, the countermeasure for the issues are proposed.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.793-808
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• 2009

This paper presents procedure and prediction method of internal and external stabilities when designing D.C.M, with main factors to be considered, such as chemical reaction of additive, physical properties of stabilized body and mixing strength. Results show that through case studies, a design unconfined compressive strength of stabilized body (hereafter referred to as 'compressive strength') directly depends on the quantity of cement, which is decided by laboratory test, and the compressive strength enormously affects internal and external stabilities. So laboratory mixing test to obtain the compressive strength for design allowable stress should be given careful considerations.

• Structural Engineering and Mechanics
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• v.74 no.2
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• pp.255-266
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• 2020

The main requirements of modern welded metal structures are the load-carrying capacity (safety), fitness for production, and economy. The primary objective of attaching longitudinal stiffeners is to improve the buckling strength of relatively thin compression panels. This paper gives several comparisons for stiffened plates with different loadings (static, dynamic), different shape of stiffeners (flat, L-shape, trapezoidal), different steel grades, and different welding technologies (SMAW, GMAW, SAW), different costs to show the necessity of a combination of design, fabrication and economic aspects. Safety and fitness for production are guaranteed by fulfilling the design and fabrication constraints. The economy is achieved by minimizing the cost function. It is shown that the optimum sizes depend on the welding technology, the material yield stress, the profile of the stiffeners, the load cycles and the place of the production.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.541-548
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• 2002

This paper presents the results of stability analyses on soil-reinforced segmental retaining walls in a tiered arrangement. As-built design sections of four different walls were analyzed within the context of the limit equilibrium-based current design guidelines. The appropriateness of the original designs were then evaluated. Slope stability analyses against the compound failure mode, which Is frequently Ignored during design, were additionally peformed based on the method recommended by FHWA design guideline. The results indicate that the as-built designs of most of the walls examined do not meet the minimum factors of safety for the external and internal stabilities, and for the compound failure mode. The implications of the findings from this study are discussed.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.551-561
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• 2006

Incheon bridge project is to construct total 12km long bridges on the sea consist of 800m span length cable stayed bridge, approach bridge and viaduct bridge based on LRFD design specification. To design pile foundations by RCD of each bridge unit, total 4 number of preliminary full scale pile load tests with Osterberg cell method were carried out on the piles for testing. The test load was planned to more than the expected design ultimate capacity and about 29,000tons maximum load was recorded. From the interpretation of test results, design parameters are evaluated and applied to the design. Preliminary pile load test plan and detailed execution of pile load tests are introduced and summarized. The resistance factors are presented for pile design of Incheon Bridge Project in LRFD considering variation of ground conditions and number of test piles.

• Journal of the Korean Geotechnical Society
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• v.28 no.3
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• pp.5-14
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• 2012

In the current design codes for anti-freezing layer, the thickness of anti-freezing layer is calculated by freezing depth against the temperature condition. Therefore, they have a tendency of over-design and uniform thickness without the considerations of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential for studying the appropriateness and bearing capacity of road foundation materials as well as their seasonal and mechanical properties to take an appropriate and reasonable design of the road structure system. In this paper, the freezing and bearing capacity characteristics of typical road foundation materials were evaluated in the large scale laboratory test. LFWD (light falling weight deflectometer) was used to determine the change of elastic modulus ($E_{LFWD}$) caused by to the frost heave and thaw. Furthermore, the influence of crushed natural aggregate on the freezing of the subgrade soil was studied to verify the function and effectiveness of the anti-freezing layer.

• Journal of the Korean Geotechnical Society
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• v.29 no.4
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• pp.57-65
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• 2013

Assessment of uncertainties of loads and resistances is prerequisite for the development of load and resistance factor design (LRFD). Many previous studies related to resistance factor calculations of piles were conducted for short or medium span bridges (span lengths less than 200m) reflecting the live load uncertainty for ordinary span bridges. In this study, by using a revised live load model and its uncertainty for long span bridges (span lengths longer than 200m and shorter than 1500m), resistance factors are recalibrated. For the estimation of nominal pile capacity (both base and shaft capacities), the Imperial College Pile (ICP) design method is used. For clayey and sandy foundation, uncertainty of resistance is assessed based on the ICP database. As long span bridges are typically considered as more important structures than short or medium span bridges, higher target reliability indices are assigned in the reliability analysis. Finally, resistance factors are calculated and proposed for the use of LRFD of driven piles for ordinary span and long span bridges.