한국선원통계연보에 따르면 2016년 기준 선원의 직무상 재해율 6.02%는 고용노동부에서 발행한 2016년 산업재해 현황분석에 따른 육상노동자 평균재해율 0.49%보다 12.3배 높은 것으로 나타나 선내 안전·보건과 관련한 사고율이 심각한 수준이다. 2006년 해사노동협약에는 규정 제4.3조, 제3.1조 및 제1.1조에 선원의 재해와 관련하여 선내 안전·보건 관련 규정을 두고 회원국에서 이행하도록 하고 있으며, 우리나라 선원법에서도 제78조부터 제83조까지 동 협약 제4.3조, 제3.1조 및 제1.1조 수용을 위한 법적 근거를 마련하였다. 특히, 선원법 제79조에서는 협약의 요구사항인 선내 안전·보건 및 사고예방 기준을 해양수산부장관이 정하여 고시하도록 되어 있다. 그러나 협약의 요구사항을 선원법 개정을 통해 법으로는 수용하였으나 선내 안전·보건 및 사고예방 기준의 제정과 같이 실제 이행이 되지 않고 있어 선원의 재해율이 협약이 이행되기 전과 비교하여 개선이 되지 않고 있다. 따라서 이 논문은 선원의 재해율 감소를 위한 하나의 방안으로 해사노동협약 규정 제4.3조에서 요구하는 선내안전보건기준의 법적 성질을 선박소유자의 안전배려의무를 중심으로 살펴보고 그 이행 및 집행을 위한 제도적 개선사항을 제안하였다.

본 논문에서는 기능경사재료 보 고유벡터의 변화도 산정을 위한 해석 정식화를 섭동법에 기초하여 제시한다. 불확실인수로는 기능경사재료 보의 중앙면에서 보의 축을 따르는 방향으로 공간적 불확실성을 가지는 재료탄성계수를 택하였다. 두께 방향으로의 탄성계수 변화는 원래의 지수함수를 따르는 것으로 가정하였다. 정식화에서는 고유벡터에 대한 선형 Taylor전개 를 적용한다. 수치예제로는 보의 중앙면에 대하여 대칭인 탄성계수를 가지는 단순지지보를 택하였다. 몬테카를로 해석을 함 께 수행하여 제안한 정식화가 합리적인 결과를 주는지 확인하였다. 해석을 통하여 몬테카를로 해석과 제안된 방법에 의한 결과가 고유모드의 평균 및 표준편차에서 거의 동일한 결과를 제시함을 볼 수 있었다. 제안된 방법을 통하여 고유모드의 표 준편차 형상을 쉽게 산정할 수 있다. 고유모드의 평균중심 변화량은 고유모드의 차수에 관계없이 그 고유모드 대비 한 개가 더 많은 경사 0인 점을 가지게 된다. 또한 평균 고유모드형상으로부터의 변화량은 저차 모드보다 고차모드에서 더 크게 나 타남을 알 수 있었다.

This paper presents the design, analysis, and experimental evaluations of precast reinforced UHPC (ultra high-performance concrete) beams with a new design concept of non-uniform flexural members. With outstanding mechanical properties of UHPC which can develop the compressive strength up to 200MPa, the tensile strengths up to 8~20MPa and the tensile strain up to 1~5%, a non-uniform structural shape of UHPC flexural beams were optimally designed using three-dimensional finite element analysis. The experiments were carried out and compared with the design strength in order to verify the performance of them. Proposed non-uniform UHPC beams were evaluated by a series of three-point beam loading test as well as estimated by design bending and shear strength of members. The newly designed UHPC beams show excellent performances not only in transverse load capacities but also in deformation capacities.

구조물의 내풍성능을 개선하기 위하여 지난 수 십 년간 진동제어장치가 사용되어 왔다. 진동제어장치는 구조물의 등가감쇠비를 증가시킴으로써 진동에 대한 저항성을 증가시키는 효율적인 방안이지만, 설치와 운영에 많은 비용이 요구되고 있다. 진동제어장치와 등등한 감쇠효과를 가지면서 영구적으로 구조물 자체의 감쇠비를 증가시키기 위한 고감쇠 물질에 대한 연구가 증가하고 있다. 본 연구에서는 굵은 골재에 폴리우레탄이 코팅된 고감쇠 콘크리트 재료의 감쇠성능을 평가하기 위한 실험과 분석이 이루어졌다. 고감쇠 물질로 제조된 단순보에 대한 자유진동실험을 수행하여 각 모드별 특성을 파악하였으며 특히 감쇠비를 추정하여 감쇠물질에 의한 감쇠증가량을 정량적으로 평가하였다. 비교평가를 위하여 기존 콘크리트 재료로 제조된 보에 대한 실험 또한 병행하여 수행되었다. 모드 분석에 의한 감쇠비 추정결과 고감쇠 보는 각 모드별 약 10%의 감쇠비를 가지는 것으로 나타났으며, 이는 일반 보의 감쇠비 1%에 비 하여 매우 높은 감쇠증가량을 보이고 있다. 이러한 결과로부터 폴리우레탄 코팅 고감쇠 재료를 이용하여 구조물의 감쇠성능확보가 가능할 것으로 판단된다.

A parametric study was carried out to gain an insight about structural performances considering abnormal behavior effects in high strength steel pipe strut system. Six load cases were considered as undesirable deflections of strut structures, which are basic load combination, excessive excavation situations, impact loading effects, additional overburden loads, load combinations, and 50% reduction of strut length. Subsequent simulation results present various influences of parameters on structural performances of the strut system. Based on the results, we propose methods to prevent unusual behaviors of pipe-type strut structures made of high strength steels.

The curved beam has a complicated behavior compared to a straight beam due to torsional and warping. Therefor, in this study, eigenvalue analysis was performed for curved beam with different shape(I-shape, T-shape, box-shape) corresponding to the same value of the moment of inertia. As a result the curved beam with box-shape section had a larger natural frequency value than the other curved beam. Also, the dynamic analysis results showed that the largest result was obtained at 826.18MPa in the T-shape curved beam when the gyeongju earthquake was applied.

In this study, the long-term performance of FRP Hybrid Bar made by hybridizing FRP (Fiber Reinforced Polymer) with ordinary reinforcing steel bars was experimentally examined as a part of the development of alternative materials for RC (reinforced concrete) structures especially located in marine or harbor areas. In order to evaluate the field exposure of the FRP Hybrid Bar, the specimen was prepared and the corrosion behavior was evaluated by letting the specimen exposed to the field conditions in the west coast of South Korea. The purpose of this study is to provide important data as a material countermeasure to reduce corrosion of reinforcing steel in future marine port concrete structures based on the results obtained through this study.

As buildings are becoming larger, demand for large-scale composite columns for heavy load is increasing. Welded built-up CFT column (ACT Column I) previously developed by authors of this study is structurally stable and economical. Characteristic of welded built-up CFT column is that there is a limitation of cross-sectional size and application of external diaphragm connection to ensure continuity of rib. Then, composite mega column (ACT Column II) was developed to improve limit of cross-sectional size. Composite mega column has a closed cross section like welded built-up CFT column, but thick plate is inserted between cold-formed steel to expand cross section size. However, when external diaphragm connection is applied to composite mega column, amount of steel is increased greatly and interference with finishing material occurs. In this study, internal diaphragm connection is applied through characteristic of composite mega column to which beam flange or stiffener can be attached to plate. In order to analyze this, simple tensile experiment of composite mega column connection with T-shaped stiffener was performed.

A parametric study was carried out to gain an insight about structural performances considering abnormal behavior effects in high strength steel pipe strut system. Six load cases were considered as undesirable deflections of strut structures, which are basic load combination, excessive excavation situations, impact loading effects, additional overburden loads, load combinations, and 50% reduction of strut length. Subsequent simulation results present various influences of parameters on structural performances of the strut system. Based on the results, we propose methods to prevent unusual behaviors of pipe-type strut structures made of high strength steels.

The paper presents an experimental study on shear behavior of RC beams retrofitted with Uni-Directional Narrow Fabric to improve seismic performance. Experimental parameters include the type of fiber, spacing of the fiber, and the ratio of transverse reinforcement. Also, Static loading test was performed on twelve shear-critical specimens. An experimental result were analyzed to investigate the contribution of shear strength and failure modes of the specimens retrofitted or strengthened with Uni-Directional Narrow Fabric compared to the non-retrofitted the specimen. In order to derive the shear strength model according to the spacing of the fiber, the experimental results were compared with the conventional shear strength model of RC elements retrofitted with FRP.

Unlike column-to-beam connections in reinforced concrete frames, column-to-beam connections are generally of the same type. Vertical load (D.L + L.L) and horizontal load (wind load, seismic load) are not the same in the upper and lower flange stress history. In the case of beams bonded to synthetic CFT columns, the tensile force is transmitted through the steel pipe column, and the compressive force is transmitted to the filled concrete, so the seismic performance is excellent even if the column has a relatively thin cross section. Also, in case of beam the composite CFT column, tensile force is taken by the steel pipe column, and the compressive force is caught by the inner concrete, and the shape of the column joint can be changed. In this study, the stress distribution of buildings is investigated according to the size and characteristics of the building, and the load history of the upper and lower flanges according to the building type is checked to show the structural possibility of the Asymmetric Diaphragms joint.

The purpose of this study was to analyze some parameters’ effects on buckling behavior of Sinusoidal Corrugated Web using finite element analysis program. Studying buckling behavior is one of the most important things to design sinusoidal corrugated web girders and predict the shear performance. In this paper, Four parameters of Sinusoidal Corrugated Web, which are thickness( ), height( ), wave height( ) and wave length( ), were selected for buckling behavior analysis. Via buckling analysis, it is shown that  ,  and  have influence on shear buckling stress, Initial stiffness and reduced strength after buckling.

A small dam is of hydraulic structures, which is always exposed to risk by flood, and it’s very important to ensure structural safety. A probabilistic analysis, quantifying variable as a risk factor to ensure safety of small dam, identifying its coefficient of variation, which has become increasingly important. In this study, the risk of seepage failure of foundation within a small dam was estimated based on flood scenarios by rainfall quantile. The final compound risk was evaluated combining probabilities, related to seepage failure and flood level. The seepage failure probability was estimated by performing seepage analysis depending on the water level difference between upstream and downstream in small dam. The probable flood level was estimated by considering hydraulic uncertainty associated with channel geometry, and movable gate operation during the flooding season, applied a probable flood considering hydrologic uncertainty evaluated by Bayesian approach. The safety evaluation of small dam with probabilistic-based compound risk expect to use the index for hydraulic structure design in the future.

As buildings are becoming larger, demand for mega-sized composite columns (over 1-meter diameter) is increased. We have developed and commercialized welded built-up CFT column (ACT Column I) since 2005 which are structurally stable and economical using cold-formed steel with rib. However, there has a limit in size of cross section (618˟618mm) by a fabrication facilities. And due to characteristics of closed cross section, there has a limit to construction of connection of moment frame. Composite mega column (ACT Column II) has same concept of forming closed cross section. But in order to enlarge cross sectional size, thick plate is inserted between cold-formed steels. Since composite mega column can control thickness and width of thick plate, steel or composite beams can be directly attached to the connection. In this study, we propose strength formula of composite mega column to beam connections with T-shaped stiffener as internal diaphragm and verified through finite element analysis and simple tensile experiment.

Theories for composite structures are too difficult for design engineers for construction. The purpose of this paper is to demonstrate to the practicing engineers, how to apply the advanced composite materials theory to the structures. In this study, the natural frequency of a laminated cantilever beam was studied. An ultrasonic testing platform was employed to resonate the beam, and its time domain signal was optically measured. The natural frequency was quantified through the fast Fourier transform of the waveform, and the result showed good agreement with a theoretical estimation from the Euler-Bernoulli beam theory. This study is expected to provide a dynamic evaluation technique for laminated cantilever beam structures.

Diagonally reinforced concrete coupling beams (DRCB) play an important role in coupled shear wall systems since these elements dissipate most of seismic input energy under earthquake loading. For reliable seismic performance evaluation using nonlinear response history analysis, it is important to use an accurate analytical model for DRCBs. In this study, the Pinching4 model is used as a base model to simulate the cyclic behavior of DRCBs. For simulating the cyclic behavior of DRCBs using the Pinching4 model, the analytical parameters for backbone curve, pinching and cyclic deterioration in strength and stiffness should be computed. To determine the proper values of the constituent analytical parameters efficiently and accurately, this study proposes the empirical equations for the analytical parameters using regression analyses. It is shown that the hysteretic behavior of coupling beams can be simulated efficiently and accurately using the proposed numerical model with the proposed empirical equations of model parameters.

The coupled shear wall system with coupling beams is an efficient structural system for high-rise buildings because it can provide excellent ductility and energy dissipation to the buildings. The objective of this study is to simulate the hysteretic behavior of diagonally reinforced concrete coupling beams including pinching and cyclic deteriorations in strength and stiffness using a numerical model. For this purpose, coupling beams are modeled with an elastic beam element and plastic spring element placed at the beam ends. Parameters for the analytical model was calibrated based on the test results of 6 specimens for diagonally reinforced concrete coupling beams. The analytical model with calibrated model parameters is verified by comparing the hysteretic curves obtained from analysis and experimental tests.

2016년에 1종이 추가로 보고되어, 현재 한국 연안에는 총 4종의 바다뱀이 분포하고 있다. 기후변화 등으로 한국 연안에 바다뱀의 년 중 서식 가능성이 높아지고 있으나 인적, 물적 한계로 인하여 관련연구가 미비한 상태이다. 국내 연안 내 바다뱀 분포에 대한 정보 및 샘플을 시민의 활동을 통해 확보하기 위하여 한반도의 해안지역과 제주도에 제보를 권하는 바다뱀 포스터와 현수막을 게시하고 제보를 접수하였다. 연구수행결과 2013년 3월부터 2016년 12월 사이 45건의 신뢰성 있는 제보가 접수되었다. 바다뱀 제보는 18건으로 주로 제주도와 남해안에서 접수되었으며, 시기적 으로는 8-11월 사이가 많았다. 총 3종 18건의 바다뱀 분포정보와 2종 13개체의 포획이 가능하였다. 바다뱀의 오제보는 27건이었는데, 육지뱀이 7건, 어류가 18건, 무척추동물과 사물이 각 1건이었다. 자료를 바탕으로 시민을 활용한 효율적 바다뱀 조사방법에 대한 제언을 하였다.