• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.3
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• pp.31-36
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• 2007

The excavator is complex machinery which has widely used in the construction site, deck of harbor and deep sea. The one of important issue of excavator system in recent is an automation of it in order to improve a working efficiency, a convenience working circumstance and work satisfaction. However, since there are large nonlinearities of control circuit, actuating cylinder, joiners of hydraulic units and changing loads etc., it is difficult to develope an automatic excavator system. Therefore, in this study, toy scale pneumatic excavator system is constructed and the remote control system is installed on it, before developing the automatic excavator system. In order to design the control system of the developed pneumatic excavator system, the transfer function is obtained using signal processing method and the controller gains of PID are decided based on CDM(coefficient diagram method). The obtained transfer function and the performance of the proposed control system is evaluated through experiments and computer simulation.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.255-266
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• 2000

Since 1993, Seohae grand bridge has been continued construction for 7 years and will be completed late this year. The bridge is a part of west sea castal highway and consists of 3 types of bridge including precast segmental method, free cantilever method and cable stayed bridge. A cable stayed bridge is the core of this bridge and it consists of 5 span, symetrical cable-stayed bridge with a total length of 990 m. The main span between two H-shaped pylons extending approximately 180 M above massive foundation of a cable stayed bridge is 470 m long and an approach span of that is 260 m long respectively. The circular cofferdam with 16 ea of 25 m diameter flat type sheet pile had been applied to construct foundation. The slipform method had been applied for forming of con'c of two H-shaped pylons with 3 cross beams respectively which is varied horizontally and vertically. The deck has been erected with balanced cantilever method using movable derrick crane. The stay cables is a bundle of parallel individually protected, 7 wire high tensile strands. The strands is hot deep galvanized and sheathed with a tight high density polyethylene coating. A petroleum wax fills all the inter-wire voids. The bundle of strands to prevent from deterioration due to the ambient problem covered with high density polyethylene pipe. The Isotension method has been applied for the stressing of cable strands to ensure uniformity of force in all the strands of a syay and such works has been performed on the stay specially provided in the pylon.

• Journal of Korean Tunnelling and Underground Space Association
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• v.18 no.5
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• pp.419-429
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• 2016

In a bid to avoid the economic loss resulting from traffic jam in urban area, a deep underground road at 40 m depth has been considered and the first class disaster prevention facilities shall be applied according to domestic guideline. Automatic-monitoring fire extinguishing system designed to use for fire fighting has been widely applied at home and abroad. Recently development and commercialization through theoretical and experimental research to apply to road/railroad sector have been underway. Based on such performance of automatic fire extinguishing system, technical/economic analysis of existing water spray systems was conducted and as a result, it has demonstrated the superiority in terms of fire suppression as well as in cost efficiency. Then to commercialize this system, more diverse studies that will incorporate the characteristics of domestic tunnels are needed and should the system be promoted through institutional improvement, it's expected to become one of the advanced nations with own original technology in a life safety system industry throughout the world.

• Journal of Korean Society of Steel Construction
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• v.16 no.6 s.73
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• pp.747-757
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• 2004

With steel and concrete composite beams, the incomplete interaction between the steel and the concrete slab leads to an appreciable increase in beam deflections. Moreover, encased composite beams using a deep deck plate or hollow-core PC slabs are critical to deflection due to their inherent geometry. In this paper, by using the calculation tools that were developed for a previous study on the deflection of encased composite beams considering the slip effects and load-slip curve, the shear bond stress and additional deflection induced due to interface slip of the encased composite beam are presented. It was found that the slip effects significantly contribute to the encased composite beam deflections and result in stiffness reduction of up to 30% compared to that of full shear interaction beams. The predicted results were compared with the measurement of 18 specimens tested in this study, and comparisons show a high degree of accuracy, within 6%.

• Ocean Systems Engineering
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• v.3 no.4
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• pp.257-273
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• 2013

Top tensioned riser (TTR) is often used in a floating oil/gas production system deployed in deep water for oil/gas transport. This study focuses on the extension of the existing numerical code, known as CABLE3D, to allow for static and dynamic simulation of a TTR connected to a floating structure through a tensioner system or buoyancy can, and restrained by riser guides at different elevations. A tensioner system usually consists of three to six cylindrical tensioners. Although the stiffness of individual tensioner is assumed to be linear, the resultant stiffness of a tensioner system may be nonlinear. The vertical friction between a TTR and the hull at its riser guide is neglected assuming rollers are installed there. Near the water surface, a TTR is forced to move horizontally due to the motion of the upper deck of a floating structure as well as related riser guides. The extended CABLE3D is then integrated into a numerical code, known as COUPLE, for the simulation of the dynamic interaction among the hull of a floating structure, such as spar or TLP, its mooring system and riser system under the impact of wind, current and waves. To demonstrate the application of the extended CABLE3D and its integration with COUPLE, the numerical simulation is made for a truss spar under the impact of Hurricane "Ike". The mooring system of the spar consists of nine mooring lines and the riser system consists of six TTRs and two steel catenary risers (SCRs).

• Journal of Conservation Science
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• v.4 no.1 s.4
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• pp.3-10
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• 1995

This study focused on the reconstructional point of Shinan ship-wreck that was excavated between $1976\~1984$. The wreck, which might be sunk in the beginning of the 14th century, is regarded as a vessel of Yuan dynasty, China. This paper tried to find out some structural characteristics and principal dimensions for restoration. The Shinan shipwreck's structural characteristics are summarized as follow, 1) The Shinan shipwreck is formed V-shaped cross section with bar keel, 2) The vessel is divided 8 holds by 7 bulkheads. 3) The ship has flat type stem and transome stern. 4) A rabbeted clinker -built is basically adopted on planking joint. 5) A wooden sheathing, which means a sort of protecting board against marine insects, is covered outside of the main hull, 6) For making an watertight structure, oakum and lime mixtured t'ung-oil are used along the seam of planking and bulkhead. 7) A V-shaped deep water-way exists at both deck side. 8) The shipwreck is believed to have 2 masts at least. 9) The shiptimbers are classified as Chinese Red Pine(Pinus Massonina) which is mainly grown in the southern part of China. Considering as mentioned above the structural characteristics, Shinan ship-wreck could be classified as Chinese Fu-chuan type(복선형) of sea-going ship. The Shinan ship's principal dimensions which are calculated on the basis of Chinese traditional shipbuilding custom, are as follow, Length overall(L.O.A). : 34.80m Length water line(L.W.L) : 24.90m Breadth(B.max.) : 11m Breadth(B) : 10m Depth at keel line(H) : 3.75m Draft(D). : 3.15m Freeboard(F) : 0.65m Ratio, length/breadth(L/B). : 2.26 Ration, breadth/depth(B/D) : 3.5 Height of stem : 7m Height of stern : 10m Displacement : ab.340ton.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.3
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• pp.193-210
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• 1991

For the deckhouse or superstructure, attention is directed to the reduction of vibration from a human susceptibility point of view. The two basic requirements for obtaining a low vibration level in the accommodation are to ensure that excitation forces from propeller and/or main engine are small and to avoid resonance excitation of the hull and superstructure. In recent years increased attention has been directed towards the problems of vibration and noise in deckhouse, which have caused major problems with regard to the environmental quality in the living quarters for crews. Accordingly, in this paper, the characteristic of the vibration of deckhouse of fishing boat, of which the length/height ratio is also relatively high, are studied systematically with regard to the shape and modelling of deckhouse based on finite element method of 1-dimensional, 2-dimensional and 3-dimensional model. This study is divided into 4-part. 1st part is the global deckhouse vibration, 2nd part is the local deckhouse vibration, 3rd part consists of the estimation for stiffness of foundational support and 4th part is the application to TUNA LONG LINER of 416 ton class. For the global vibration analysis, the severity of the vibration depends on the longitudinal shear and bending stiffness of the deckhouse, on the vertical deckhouse support(fore, aft and sides). However, even if the design is technically sound, vibration problems may arise due to vertical or longitudinal hull girder or afterbody resonances. Author applied the method of this study to the analysis of, deep-sea fishing vessel of G.T. 416 ton class with relatively low height and long deckhouse, and investigated the vibrational characteristic of the fishing vessel with earlier structural feature. According to this investigation, the vibration, response of above vessel was confirmed of which main hull and deckhouse behave as one body. It is at the bottom of vibrational trouble which a accommodation part of the fishing vessel is raised, that is the local vibration for side wall, fore-aft wall and deck plate of deckhouse rather than thief fect of fore-aft vibration of deckhouse for above fishing vessel. and the resonance of main hull, deckhouse and driving system such as the main engine, propeller in exciting source is mainly brought up as the trouble.

• Bulletin of the Society of Naval Architects of Korea
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• v.11 no.2
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• pp.23-40
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• 1974

Semisubmersible 해양석유시추선의 기본설계에 필요한 파랑중(波浪中)에서 운동(運動)을 계산(計算)하는 이론적방법(理論的方法)을 제시하고 "MOHOLE"과 "SEDCO 1350-F" 석유시추선들의 운동(運動)을 해석하였다. 이 규칙파에서 운동계산을 불규칙해양파(波)에 적용하는 응용해석을 보여주었다. 현재 이론적 방법으로는 6자유도(自由度)의 운동을 해양파의 어떤 방향에 대해서도 정확히 계산할 수 있으며 계산의 정확성은 수조(水槽)에서의 모형선의 운동측정치와 실선(實船)의 운동측정치와 비교하여 증명되었다. 또 현재의 방법은 종전에 개발된 방법보다 더 일반적(一般的)인 경우를 다룰 수 있으며 결과치도 더 정확하다. 극소운동특성을 갖는 해양석유시추선과 부체(浮體)해양구조물의 설계는 경비가 비싸고 시간이 많이 드는 모형실험보다는 유체역학적(流體力學的) Parameters를 신속 정확히 자주 변경 검토해야 하는 기본설계단계에서는 정확한 이론적인 전자계산기에 의한 계산방법이 절실히 필요하다. 예상(豫想)과 같은 부가질량(附加質量)과 감쇠력(減衰力)은 Resonance 운동주기에서만 운동에 영향을 준다. 해양구조물에 작용하는 파력(波力)은 Froude-Krilov force, 부가질량(附加質量) 및 감쇠력(減衰力)과 Restoring force로 구성했으며 규칙파(規則波)에서의 6자유도(自由度) 운동방정식은 본 논문에 제시된 실험측정치(値)와 실험으로 정확도가 증명된 이론치(値)의 부가질량과 감쇠력 계수(係數)를 써서 풀었다. 규칙파(規則波)에서의 계산된 운동을 Pierson Moskowitz 해양파(海洋波) 스펙트럼과 linear superposition principle에 의해 불규칙해양파(不規則海洋波)에서의 운동을 계산하는데 사용했다. 불규칙파(不規則波)에서의 운동은 운동스펙트럼과 통계적 운동치로 나타냈다. 현재의 계산방법은 실제 기본설게에 사용되어 왔으며, 다른 응용분야는 파랑중(波浪中)에서의 파면(波面)과 Deck간(間)의 Clearance, 계류선(係留線)의 동장력(動張力)계산의 기본 Data 및 기본설계의 Draft 등 Parameters를 통(通)한 Optimum Design 등(等)이다. 파(波)의 한 방향(方向)에 대(對)한 전자계산기(電子計算機)(IBM 370 또는 CDC 6400)에 의한 운동계산은 10초(秒)미만밖에 안걸린다. 또 현재의 계산방법은 해양석유시추선뿐 아니라 이와 비슷한 부체(浮體)해양구조물과 Pipe-laying선(船) 또 Supply Boat설계(設計)에도 쓰여지고 있다.

• Journal of Korean Society of Steel Construction
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• v.19 no.4
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• pp.413-423
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• 2007

Slimfloor composite-beam systems could considerably reduce the story height of a building if the steel beam would be installed deep into the concrete floor slab. However, as the depth of the steel beam's installation is limited, it cannot cope with the various demands of building systems. To address this problem, a profiled steel beam section that can control the depth of the steel beam's and slabs' installation was developed in this study. Presented herein are the results of an experiment that was conducted focusing on the flexural behavior of the partially connected composite beams with profiled steel beams encased in composite concrete slabs. Five full-scale specimens with different slab types, with or without shear connection and reinforcement bars, were constructed and tested in this study. As a result, the shear bond stress without an additional shear connection was found to be $0.20{\sim}0.76N/mm^2$due to the inherent mechanical and chemical bond stress.

• Journal of Korean Association for Spatial Structures
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• v.18 no.4
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• pp.113-121
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• 2018

U-flanged truss beam is composed of u-shaped upper steel flange, lower steel plate of 8mm or more thickness, and connecting lattice bars. Upper flange and lower plate are connected by the diagonal lattice bars welded on the upper and lower sides. In this study the structural experiments on the U-flanged truss beams with various shapes of upper flange were performed, and the flexural and shear capacities of U-flanged truss beam in the construction stage were evaluated. The principal test parameters were the shape of upper flange and the alignment space of diagonal lattice bars. In all the test specimens, the peak loads were determined by the buckling of lattice bar regardless of the upper flange shape. The test results have shown that the buckling of lattice bar is very important design factor and there is no need to reinforce the basic u-shaped upper flange. However, the early lattice buckling occurred in the truss beam with upper steel bars because of the insufficient strength and stiffness of upper chord, and the reinforcement in the upper chord is necessary. The formulae of Eurocode 3 (2005) have presented more exact evaluations of lattice buckling load than those of KBC 2016.