• 대한조선학회논문집
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• 제32권1호
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• pp.25-36
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• 1995

확률적인 접근법으로서의 신뢰성 해석법의 소개와 이의 선체 구조 강도 평가 방법에의 적용에 관해 고찰하였다. 당사에서 건조한 유조선 및 살물선 34척을 대상으로 인장 항복강도, 보강판의 압축 최종강도, 그리고 선각 거어더의 최종강도 등 몇몇 대표적인 종강도 파괴양식에 대해 신뢰성 해석을 수행하였다. 해석결과로서 각 선박에 대한 신뢰도 지수를 보이고 종강도에 대한 신뢰성 해석시의 목표 신뢰도 지수를 제시하였다. 배길이와 건조연도에 따른 신뢰도 지수의 변화를 검토하였으며 결과로서 각 선박의 안전도가 큰 차이를 보임을 알 수 있었다. 각 선박에 대해 균일한 수준의 신뢰도를 제공하기 위하여 부분 안전계수를 이용한 새로운 강도 평가 기준을 마련하였다. AFOSM 방법 및 신뢰성 조건(RC) 방법에 따라 부분 안전계수를 계산하고 이를 비교하였으며 원하는 신뢰도를 줄 수 있는 설계식을 RC 방법으로 구하였다. 부분 안전계수로부터 구한 새로운 설계식을 사용하여 신뢰성 해석을 수행한 선박에 대해 재해석을 실시하였다. 그 결과 처음보다 많이 개선된 균일한 수준의 신뢰도를 얻을 수 있었고 이로부터 신뢰성 해석의 적용가능성과 유용성을 확인하였다.

• 지질공학
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• 제27권1호
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• pp.31-40
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• 2017

한계평형법에 의한 비탈면 안정성 해석은 활동면을 반복적인 해석 후 임계면을 설정하여 해석을 수행하고, 지반이 균질한 경우에만 적용이 가능하며, 안전율만 산정 할 수 있는 단점이 있다. 그러나 강도감소법을 적용한 해석에서는 수행자가 여러 가지 측면에 대해서 판단하고, 안전율을 산정 할 수 있는 장점 등이 있다. 본 연구에서는 동일한 크기의 비탈면을 대상으로 한계평형해석과 강도감소법을 활용하여 경사도 변화에 따른 두 해석법 간의 안전율 변화 양상과 점착력과 내부마찰각의 변화에 따른 안전율 변화 추이를 비교 분석하였다. 각각의 해석법에 따른 안정해석 분석 결과 지반내 응력, 변위와 변형률 등을 종합적으로 검토할 수 있는 강도감소법이 활용도가 높을 것으로 판단된다.

• 한국지반신소재학회논문집
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• 제17권2호
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• pp.19-31
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• 2018

최근 도시의 안전을 심각하게 저해시키는 지반함몰현상이 증가하는 추세에 있어 대책이 필요한 상황이다. 지반함몰 발생 시 긴급복구공법에 사용될 산업부산물을 활용한 뒤채움재를 개발하는 것이 본 연구의 목적이다. 이를 위해 유동성 채움재 설계기준에 의거하여 목표성능을 도출하였고, 플로우값, 일축압축강도, 초기응결시간, pH시험 등 실내시험평가를 통해 개발된 재료의 적용성을 검토하였다. 또한 현장실험을 통해 고유동성 채움재의 조기강도에 대한 성능검증과 긴급복구를 위한 시공성을 확인하였다. 평가결과 시멘트의 비율이 4% 이상일 경우 재 굴착이 가능한 장기강도보다 크게 측정되어 긴급복구목적에 적합지 않은 것으로 나타났다. 최적배합비는 저회와 석고의 비율이 약 50:50, 시멘트의 비율이 2%로 나타났다.

• 한국안전학회지
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• 제16권1호
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• pp.59-64
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• 2001

Even though there is a guideline for the required strength of pipe support in inspection, it does not mean the nominal strength which can be used for the form work design. And, Concrete Specification defines that the pipe support should be designed according to the steel design guidelines but the design details are not provided, such as buckling length and the sectional modulus, etc. For the better prediction of strength of pipe support, the slenderness ratio of support which reflects the boundary condition should be considered. In this paper, the elastic buckling formula based on the slenderness is derived. The formula contains the strength reduction factor that consider the strength deduction caused by initial lateral deformation and is 0.65 consistently regardless of boundary conditions. And the coefficient of effective buckling length is calculated from the experiment.

• 한국안전학회지
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• 제20권3호
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• pp.158-163
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• 2005

This paper is focusing on the model to predict the ultimate shear strength on joints of composite system (RCS) with reinforced concrete columns and steel beams considering the transverse beam. It reviews the ratio of experimental shear strength to design strength calculated by existing desist equations which are proposed by Kanno, Wight, Noguchi and the rising of strength by the transverse beams. When the shear strength of joints is estimated, it is necessary to do research work for the stress transfer mechanism considering two concrete strut of inner and outer panel by web of the transverse beam. In order to confirm it requires further experimental and analytical study.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 봄 학술발표회 논문집
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• pp.73-81
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• 1995

In Korea, the pilot construction of the first high-speed railroad on the Seoul-Pusan has already started 2 years ago. In the thesis, an attempt is made to develop reliability-based integrity-assessment models for the computer-aided control and maintenance of high-speed railroad bridges. The strength limit state models for PC railroad bridges encompass the bending and shear strengths as well as the strength interaction equations which simultaneously take into the element and system reliablities of the proposed limit states and reliability models. Then, the actual load carrying capacity and the realistic safety of bridges are evaluated using the system reliability-based equivalent strength, and the results are compared with those of the element reliability-based or conventional methods. Various parametric studies are performed for the proposed reliability-based safety and integrity-assessment models using the actual PC box girder bridges used in the pilot construction. And the sensitivity analyses are performed for the basic random variables included in strength limit state models. It is concluded that proposed models may be practically applied for the rational assessment of safety and integrity of high speed railroad bridges.

• International Journal of Safety
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• 제8권1호
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• pp.1-5
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• 2009

The CFRP composite has unique properties that offer high strength and stiffness, even though it has light weight. Therefore it can be used in many industrial applications. When mechanical fasteners are used for joining composites, high stress concentrations appear near the edge of holes prepared for accommodating structural bolts and rivets. This presence of high stress concentrations can be a source of damage. The aim of this work is to evaluate fracture behavior and patterns of plain woven CFRP with circular hole and repairing patch element. The maximum strength and pattern for the plain woven carbon composite specimen with the repaired circular hole were examined. From the results, we show that repairing of the CFRP composite specimen with ($\pi$) 3~5 mm of circular hole diameter results in load rising effect and the repairing is more effective as bigger hole specimen.

• 한국생산제조학회지
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• 제21권2호
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• pp.221-224
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• 2012

This paper presents the strength safety of a hybrid alarm valve by a finite element analysis. The stress and strain of a conventional hybrid alarm valve are calculated for the given maximum test pressure of 2MPa. Especially, the FEM computed maximum stress of a conventional hybrid valve is only 18.6% of yield strength, 370MPa. This means that the conventional valve is designed with a thick thickness of a valve structure. But, new hybrid alarm valve model, which is developed by optimized design method in this study, shows more low level of 43% in maximum stress and strain compared with that of a conventional hybrid valve. These results may recommend the reduction of a weight and a dimension for an optimized hybrid alarm valve.

• 한국안전학회지
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• 제18권4호
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• pp.105-109
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• 2003

Structure surfaces damaged due to many causes are repaired by several special mortars. But wide studies about the permeability of these mortars were rarely conducted. In this study compressive strength test, flexural strength test and bond strength test of these mortars were conducted. And chloride ion penetration test was also conducted to explore the permeability charcteristics of selected repair mortars. This test was carried out following the standard ASTM C1202-91. Colouriemtric penetration depth can be drawn from these test results using a relationship equation between colourimetric penetration depth and charge passed which C. Andrade suggested. Diffusion coefficient can be calculated by CTH rapid method. To the end, the present study can provide a firm base for the application of repair mortars to concrete structures.

• 한국안전학회지
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• 제20권3호
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• pp.126-133
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• 2005

Behavior of saw-dust concrete has not studied because many people have thought that saw-dust concrete cannot be applicable for structural member, up to now. This study is to findout how much the concrete can be structurally applicated. 5mm grid sieve was used to select satisfactory sawdust for better concrete quality. Test molds size of ${\phi}10{\times}20cm$ long were made of normal without sawdust, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.4%, 1.6%, 1.8% 2.0%, for making concrete strengh of 180kg, 210kg, 240kg, 270kg which they are normally used in practice presently. A various strengths tests such as compressive splitting tensile, flexible strength behavior of structural member named beam using size of $20{\times}30{\times}120cm$ have been done for the structural aspects. Tensile strength shows that it can be more affected than higher strength of it.