• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.5
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• pp.31-40
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• 2009

In this paper, a trial-error based method is presented to calibrate added mass models through numerical iterations minimizing the difference between the measured frequency data and its numerical simulation result for a dam floodgate. Earthquake analysis of the real floodgate for which the on-site hammering vibration test is performed show that the classical Westergaard added mass model gives relatively larger values in the maximum earthquake force and the maximum total displacement than the present added mass model, based on the calibration of on-site measurement data.

• Tunnel and Underground Space
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• v.9 no.2
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• pp.141-148
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• 1999

Distinct element simulation in jointed rock masses is largely dependent upon the joint constitutive equation used. This paper describes the differences between the Barton-Bandits (BB) and the Mohr-Coulomb (MC) joint constitutive models for the stability analysis of the jointed rock slopes. The BB model, which allows the modelling of the dilation accompanying shear, predicts results very similar to the present condition of slopes. Consequently the 10 cm thick shotcrete was proposed for the reinforcement of those slopes. The MC model, however, in which the dilation angle is constant, is relatively insensitive to the behaviors of joints.

• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.425-430
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• 2010

This paper investigates the seismic behavior of a prefabricated composite column which is made by onsite connection of precast composite column segments to accelerate bridge construction. Quasi-static cyclic loading tests were performed on three prefabricated composite columns with different connection details to find their seismic capacity. Test results show that the onsite connections remains in elastic range and no slip is observed as designed in spite of plastic hinge formation at the column. The test results also indicate that the prefabricated composite column has better overall seismic capacity compared to a conventional reinforced concrete column with seismic details.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.167-180
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• 2004

In this study finite element analysis using hyperbolic model was performed to predict the characteristics of stress-strain behaviour on concrete face earth dam (CFED : a tentative name) raised with coarse-grained materials corresponding to the face slab bedding zone of concrete face rockfill dam (CFRD). The results of finite element analysis were compared with field monitoring data, and the comparison showed a good agreement. And, the analysis results including locus of maximum displacement, maximum stress, stress concentration, and irregular load transfer would be used to devise rational field monitoring schemes for construction management and quality control during construction of CFED.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.13 no.3
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• pp.173-183
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• 1993

Four wave gauges of pressure type were installed for about one month(1992. 2~3) for the analysis of wave agitations induced by the intrusion of long-period incident waves inside and outside of Donghae Harbor. Helmholtz natural period and second peak period of seiche in Donghae Harbor are found to be approximately 17.1 and 5.5 minutes from the spectral analysis of measured long-period wave data. Amplification ratio at Helmholtz natural period reaches about 10 which is five times as lagre as that of Youngil Bay, but wave amplitudes ill harbor were about 10 em during the measurement period which are relatively small.

• Journal of the Korean Geosynthetics Society
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• v.6 no.2
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• pp.9-15
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• 2007

Bedding zone in CRFD (Concrete Faced Rockfill Dam) requires bearing capacity to support the concrete face slab uniformly. Also, shear strength which is a key factor in slope stability and impermeability which is to prevent a loss of soils in case of leakage of concrete slab face are needed. In this study, trial prototype construction for bedding zone in CRFD was performed to investigate the compaction characteristics of bedding zone according to the frequency of compaction, water contents and so on. As a results of series of field test, the compaction characteristics of bedding zone in CRFD was affected considerably by the depth of compaction layer and frequency of compaction.

• Journal of Korean Society of Steel Construction
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• v.12 no.2 s.45
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• pp.123-131
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• 2000

In this study, both experimental and analytical study for behavior of the existing composite steel box girder bridges, constructed along with the procedure of continuous placing slab, are conducted to establish the validity of the proposed model. The layer approach is adopted to determine the equilibrium condition in a section to consider the different material properties and concrete cracking across the sectional depth, and the beam element stiffness is constructed on the basis of the assumed displacement field formulation and the 3-points Gaussian Integration. In addition, the effects of creep and shrinkage of concrete for time-dependent behavior of the bridge are taken into consideration. Finally, both analytical and experimental results are compared.

• Computational Structural Engineering
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• v.4 no.4
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• pp.14-23
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• 1991

T/G 가동중 발생한 Gear Box 파손원인을 조사하기 위하여 실시한 현장측정결과를 이용한 결과, 다음과 같은 사실을 알 수 있었다. 1) 현장 측정치와 구조해석 결과를 토대로 판단해 볼 때 본 연구대상 구조물의 구조상 문제는 없는 것으로 판단된다. 특히 측정된 진동변위를 여러기준과 비교해 볼 때 기계 가동시 구조물에 발생하는 진동은 사람이 감지할 정도에 속한다. 2) 본 연구대상 구조물과 기계의 진동수 차가 커 공진역을 벗어나므로 기계와 구조물이 공진을 일으킬 가능성은 없으며, 감쇠비에 따른 구조물의 동적응답에는 큰 변화가 없는 것으로 판단된다. 3) 구조물설계회사에서 사용한 구조해석 모델은 근사적 모델로서 구조해석 결과 안전한 값이 얻어졌다. 따라서 이 모델을 사용하여 기초설계를 실시할 경우 안전성 문제는 없는 것으로 판단되나, 다소 경제성이 문제가 되었을 것으로 사료된다. 4) 기계제작회사에서 제시한 해석자료의 불충분으로 기계제작회사의 구조해석 모형에 대해서는 충분한 검토를 실시할 수 없었으나 기계제작회사의 해석결과를 측정치와 비교해 볼 때 측정치를 훨씬 초과함을 알 수 있었다. 이는 해석모형 작성시 구조물과 하중의 실제 상황을 제대로 반영하지 못했기 때문으로 판단되며 따라서 해석결과는 타당성이 없어 보인다. 이상의 사실을 토대로 판단해 볼 때 Gear Box 파손의 주된 원인은 구조물의 결함이라기 보다는 기계 자체의 결함인 것으로 판단되나 기계에 대한 조사는 본 연구대상이 아니므로 이에 대한 검토는 실시하지 않았다.

• Journal of the Korean GEO-environmental Society
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• v.5 no.1
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• pp.5-12
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• 2004

Soft foundation is extensively distributed in coastal areas including our local regions. Embankment load on such soft foundation causes displacement due to lack of base ground supports. Long-term consolidation can result in settlement and destruction of shear failure and structure. Therefore, a variety of vertical drain methods are applied to construction sites to prevent base from breaking and changing for secure construction. This study analyzed the patterns of changes displacement to determine efficient range of improvement since range of vertical drain material determines vertical and horizontal changes based on the width range of under ground improvement. Changes of intensity with distance from embankment edge were also analyzed in the field study of embankment slope.

• Geotechnical Engineering
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• v.14 no.1
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• pp.15-28
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• 1998

The use of EPS application to construction field was introduced in this country very recently. Nevertheless, approximately a total of 210,000m3 of EPS application was conducted in less than four years. Main app.lication areas for the EPS method are : (1)backfill behind a bridge abutment constructed on soft clay soil, (2)embankment constructed on soft clay soil, and (3)backfill of gravity wall. Among these, about 70oA of EPS are used for (1) and (2) deb cribed above. In this study, an invesitgation was held for the application of the EPS method to backfill of a bridge abutment which was constructed on soft clay soil. Several instruments were installed around the construction site to invesitgate the behavior of the system. Then a Finite Element Analysis was conducted for comparison.