• Journal of Korean Society of Steel Construction
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• v.25 no.6
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• pp.601-612
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• 2013

In the present study, details of the TSC beam-to-PSRC column connection for low and middle seismic zones were developed. For ease construction, the top and bottom flanges of the steel section of the TSC beam were discontinuous at the joint face on purpose, while the web passes through the joint. Thus, tensile resistance of the top and bottom flanges is not considered in the calculation of nominal strength of the connection. Cyclic loading tests on two interior connections and an exterior connection were performed to verify the seismic performance. The test parameter for two interior connections was the depth of the TSC beams: 600 and 700 mm including the slab depth. The test results showed that the nominal strength of the connections predicted by KBC 2009 correlated well with the test results. The connection specimens exhibited relatively good deformation and energy dissipation capacities, greater than the requirements for the ordinary and intermediate moment frames. Ultimately, the connection specimens were failed at the story drift ratios of 3.0 to 4.0 % due to local buckling and tensile fracture of the web of the TSC beam passing through the joint. By modifying the existing provisions of ASCE, the joint shear strength of the TSC beam-PSRC column connection was evaluated.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1817-1821
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• 2010

본 연구에서의 지리정보시스템(GIS)을 이용한 사방댐 입지선정모델 개발은 산사태 발생 예측을 위한 사면안정성 평가 기준을 개발하여 사방댐 지점을 선정하기 위하여 체계적으로 표준화된 시스템을 구축하는 것이 목표이며, 2002년 태풍 '루사'와 2003년 태풍 '매미'에 의하여 토석류와 산사태가 발생한 서부경남 지역의 38개 지점에 대하여 항공사진 수집 및 현장조사를 수행하고, 산사태 발생에 관계되는 강우, 지형, 지질 및 토양, 임상 등을 인자로서 규정하였다. 연구결과 서부경남지역에서 발생한 산사태는 지리산, 가야산, 좌굴산 등 EL. 500m 이상의 비교적 고도가 높은 산악지역에서 지형성 집중호우에 의하여 발생하는 것으로 분석되었으며, 강우량과 산사태의 상관분석결과 시강우량 70mm 이상 및 누가강우량 230mm 이상에서 산사태의 발생빈도가 높은 것으로 나타났다. 또한 산사태 발생지점에서의 고도(평균해수면 기준)와 능선의 고도와의 비를 백분율로 계산하여 빈도를 살펴보면 산사태 발생지점이 능선의 90% 이상의 고도에서 산사태의 발생빈도가 53%로 가장 높고, 80-90%는 21%, 70-80% 16%의 순으로 산사태 발생빈도가 감소하고 있으며, 고도가 더욱 낮아져 산사태 발생지점이 60% 이하로 내려가면 산사태 발생빈도는 급격히 감소한다. 예를 들어 능선의 고도가 1000m일 경우 900m 이상의 고도(90% 이상)에서 산사태 발생빈도가 가장 높고 600m 이하의 고도(70% 이하)에서는 발생빈도가 급격히 저하하는 것으로 나타났다. 산사태 발생지점의 표면 굴곡도에 따른 산사태의 발생빈도는 대부분의 평행사면에서 74%, 약간 오목사면에서 26%가 발생하는 것으로 나타났다. 각 지구의 지질 및 토양별 산사태 발생빈도는 화성암계열의 지질 및 자갈/암괴 섞인 토사의 토양에서 발생하는 것으로 분석되었고, $34-40^{\circ}$ 사면경사에서 40%, $26-34^{\circ}$ 사면경사에서 26%, $26^{\circ}$ 이하의 사면경사에서 22%가 주로 발생하였으며, $40^{\circ}$ 이상의 높은 사면경사에서는 극히 미미하였다. 또한 임상 기준으로는 침엽수림에서 주로 발생하는 것으로 나타났다. 본 연구에서는 이상의 결과를 기초로 매우 안정, 안정, 부분적 안정, 불안정, 매우 불안정, 위험 지역으로 구분하고, 평가한 결과는 불안정 33개소, 매우 불안정 5개소 등 38개소 지점 모두에 사방댐 설치가 필요한 것으로 분석되었다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.488-496
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• 2023

Ship and bridge structures are a type of long box-shaped structure, and resistance to vertical bending moment is a key factor in their structural design. In particular, because box girders are repeatedly exposed to irregular wave loads for a long time, the continuous collapse behavior of structural members must be accurately predicted. In this study, plastic collapse behavior, including buckling according to load changes of the box girder receiving pure bending moments, was analyzed using a numerical analysis method. The analysis targets were selected as three box girders used in the Gordo experiment. The cause of the difference was considered by comparing the results of the structural strength experiment with those of non-linear finite element analysis. This study proposed a combination of the entire and local sagging shape to reflect the effect of the initial sagging caused by welding heat that is inevitably used to manufacture carbon steel materials. The procedures reviewed in the study and the contents of the initial sagging configuration can be used as a good guide for analyzing the final strength of similar structures in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2A
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• pp.281-288
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• 2008

The Prestressed Concrete (hereinafter PSC) box girder bridges with corrugated steel webs have been drawing an attention as a new structure type of PSC bridge fully utilizing the feature of concrete and steel. However, the previous study focused on the shear buckling of the corrugated steel web and development of connection between concrete flange and steel web. Therefore, it needs to perform a study on the torsional behavior and develop the rational torsional analysis model for PSC box girder with corrugated steel web. In this study, torsional analysis model is developed using Rausch's equation based on space truss model, equilibrium equation considering softening effect of reinforced concrete element and compatibility equation. Validation studies are performed on developed model through the comparison with the experimental results of loading test for PSC box girder with corrugated steel webs. Parametric studies are also performed to investigate the effect of prestressing force and concrete strength in torsional behavior of PSC box girder with corrugated steel web. The modified correction factor is also derived for the torsional coefficient of PSC box girder with corrugated steel web through the parametric study using the proposed anlaytical model.