• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.106-110
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• 2004

In any large heavy industry like that of ship building, there exist a lot of complications for the arrangement of building blocks optimally for the minimal space consumption. The major problem arises at yard because of laxity in space for arranging the building blocks of ship under construction. A standardized erection sequence diagram is generally available to provide the prioritised erection sequence. This erection sequence diagram serves as the frame work. In order to make a timely erection of the blocks a post plan has to be developed so that the blocks lie in the nearest possible vicinity of the material handling devices while keeping the priority of erection. Therefore, the blocks are arranged in the pre-erection area. This kind of readiness of blocks leads to a very complex problem of space. This arises due to the least available space leading to an urgent need of an availability of intelligent spatial schedule without compromising the rate of production. There exists two critical problems ahead namely, the spatial occupation layout of pre-erection area and the emptying pattern in the spatial vicinity. The block shape is assumed be rectangular. The related input data's are the dates of erection (earliest as well as the latest), geometrical parameters of block available on pre-erection area, slack time and the like.

• Wind and Structures
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• 제21권1호
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• pp.41-61
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• 2015

The flutter stability of long-span suspension bridges during erection can be more problematic and more susceptible to be influenced by many factors than in the final state. As described in this paper, numerical flutter stability analyses were performed for the construction process of Zhongdu Bridge over Yangtze River using the commercial FE package ANSYS. The effect of the initial wind attack angle, the sequence of deck erection, the stiffness reduction of stiffening girders, the structural damping, and the cross cables are discussed in detail. It was found that the non-symmetrical sequence of deck erection was confirmed to be aerodynamically favourable for the deck erection of long-span suspension bridges and the best erection sequence should be investigated in the design phase. While the initial wind attack angle of $-3^{\circ}$ is advantageous for the aerodynamic stability, $+3^{\circ}$ is disadvantageous compared with the initial wind attack angle of $0^{\circ}$ during the deck erection. The stiffness reduction of the stiffening girders has a slight effect on the flutter wind speed of the suspension bridge during erection, but structural damping has a great impact on it, especially for the early erection stages.

• 산업공학
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• 제10권1호
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• pp.189-207
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• 1997

This paper explains a way of describing the erection sequence using the connecting relationship among blocks of a hull in shipbuilding industry. The information of the adjacent blocks such as upper, lower, right, left, front, rear, and their erection status, etd., is defined and the proper use of this allows us to determine one of the possible erection sequences. The methodology suggested also includes some useful benefits of avoiding insert blocks or maintaining stability in erection process. Further, an algorithm for generating the initial erection network is shown and this network may be a basis for designing daily erection scheduling. Some examples illustrate the procedure developed in this study and the results support the model's fidelity.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.61-66
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• 2004

In this paper an effort is made to develop an innovative spatial arrangement concept pertaining to ship building industry. The spatial scheduling is the problem that concentrates on effective planning of available space and arrangements of blocks and in a priority manner. In order to create an effective spatial scheduling. a database providing the priority has to be available to make the erection sequence. Such a system works hand in hand with erection sequence generator program The erection sequence program works on the conventional network analysis method which uses a typical parent-children idea for the calculation of the ENT(possible earliest network start time) and LNT(possible latest network start time). This program works in a cyclic manner taking turns by calculating the ENT in upward trace and LNT on the return trace thereby generating the entire erection sequence diagram for the requisite problem The generated database serves as an input data for spatial scheduling problem. When the system works it takes into consideration the entire system based on heuristic concepts as mentioned. There system uses the spatial aspects such as the available area of the P. E area and plan area of the corresponding blocks and its priority of erection from the erection sequence generator program develops the spatial scheduling arrangement. In this paper using all these concepts an innovative spatial schedule development system developed.

• 대한조선학회논문집
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• 제32권1호
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• pp.9-16
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• 1995

탑재 공정 계획은 도크 공기를 만족토록 탑재 전략과 탑재 블록 순서를 결정하는 것이며, 탑재일정 계획은 결정된 탑재 순서에 따라 블록의 탑재일을 결정하는 것이다. 일정 계획에 따라 부하 분포가 다양한 양상을 보이며, 이는 생산 비용에 영향을 미친다. 제한된 가용 자원을 효율적으로 사용하면서 최단 공기에 탑재를 완료할 수 있는 최적의 공정 계획을 수립하기 위해서는 공정 계획과 일정 계획의 다양한 조합에 대해 시뮬레이션해 볼 수 있어야 한다. 최적 탑재 공정 계획 시스템 구축을 위해서는 탑재 순서를 자동으로 생성하는 시스템과 부하 평준화 시스템이 요구된다. 본 논문에서 탑재 순서 자동 생성 방안을 약술하였다. 부하 평준화는 같은 도크 기간에 건조하는 모든 선박에 대해 동시에 행하여야 신뢰성 있는 결과를 얻을 수 있다. 이럴 경우 탐색 범위가 매우 넓어짐으로 효율적인 최적화 기법이 필요하다. 본 연구에서는 유전 알고리즘을 이용한 부하 평준화 시스템을 구현하였다. 본 시스템 개발로 일정 계획이 고려된 다양한 공정 계획 시뮬레이션이 가능하다.

• Wind and Structures
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• 제37권1호
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• pp.39-56
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• 2023

To ensure the wind stability of a long-span suspension bridge during deck erection under skew wind, based on the aerostatic and self-excited aerodynamic force models under skew wind, a computational approach of refined flutter analysis for long-span bridges under skew wind is firstly established, in which the effects of structural nonlinearity, the static wind action and full-mode coupling etc are fully considered, and the corresponding computational procedure is programmed. By taking the Runyang suspension bridge over the Yangtze River as example, the flutter stability of the bridge in completion under skew wind is then analyzed with the aerodynamic parameters of a similar bridge deck measured from the sectional model wind tunnel test under skew wind. Finally, through simulating the girder segments erected symmetrically from the midspan to towers, from the towers to midspan and simultaneously from the towers and midspan to the quarter points, respectively, the evolutions of flutter stability limits during the deck erection under skew wind are investigated numerically, the favorable aerodynamically deck erection sequence is proposed, and the influences of skew wind and static wind effect on the flutter stability of suspension bridge under construction are ascertained.

• Structural Engineering and Mechanics
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• 제45권5호
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• pp.703-722
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• 2013

In this paper a study about concrete arch bridges built by lattice cantilevers is presented. Lattice cantilevers are partial structures composed of deck, arch, piers and provisional steel diagonals, organized as reticular cantilever girders, in order to build arch bridges without the use of centrings, supports or temporary towers. Characteristics of this construction methodology with its variants are explained together with their implications in the erection sequence. Partial elastic scheme method is implemented in order to find initial forces of temporary cables and a forward analysis is carried out to follow the actual sequence of construction, by extending a procedure already applied to concrete cable-stayed bridges and to arches built by the classical suspended cantilever method. A numerical application on a case-study of a concrete arch bridge is performed together with a comparison between different methodologies followed for its construction sequence. Differences between erection by lattice cantilevers and cable-stayed cantilevers, are discussed. Results can be useful for designers in conceptual design of concrete arch bridges.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.96-100
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• 2004

In the ship building industry various problems of erection is counterfeited due to formation of bottle necks in the block erection flow pattern This kind of problems cause accumulated problems in real-time erection right on the floor, When such a problem is approached, a support data of the entire erection sequence should be available, Here planning is done by reasoning about the future events in order to verify the existence of a reasonable series of actions to accomplish a goal. This technique helps in achieving benefits like handling search complications, in resolving goal conflicts and anticipation of bottleneck formation well in advance to take necessary countermeasures and boosts the decision support system, The data is being evaluated and an anticipatory function is to be developed This function is quite relevant in day to day planning operation. The system updates database with rearrangement of off-critical blocks in the erection sequence diagram, As a result of such a system, planners can foresee months ahead and can effectively make decisions regarding the control of loads on the man, machine and work flow pattern, culminating to an efficient load management. Such a foreseeing concept helps us in eliminating backtracking related adjustment which is less efficient compared to the look-ahead concept. An attempt is made to develop a computer program to update the database of block arrangement pattern based on heuristic formulation.

• 한국안전학회지
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• 제22권6호
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• pp.55-62
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• 2007

The structural safety of long span bridges such as suspension bridges is smaller under the construction stage than in the completion. But the importance of construction sequences has been neglected in most of safety check programs. On this study is developed the structural analysis method of suspension bridges considering construction sequences and structural analyses are performed by step by step during construction. This can be used to determine the safest erection method. The results shows that the more critical structural behavior appears under construction than after completion.

• 한국구조물진단유지관리공학회 논문집
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• 제13권3호통권55호
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• pp.164-172
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• 2009

현수교는 주케이블이 목표하는 형상을 이루어 기하학적 강성을 갖도록 앵커, 새들과 같은 장치를 적용하고 있다. 지금까지의 연구에서는 두 장치를 모두 고정절점으로 단순화하여 해석하는 것이 일반적이었다. 그러나 새들의 경우 주케이블의 슬라이딩 현상이 발생할 수 있으며 이로 인하여 구조물의 응답이 달라진다. 특히 현수교의 시공단계 초기에 셋백로프를 철거하거나 셋백을 수행하지 않는 경우 새들 전후 주케이블의 장력 차이가 커지므로 슬라이딩이 발생하기 쉽다. 따라서 본 연구는 유한요소법을 이용한 케이블의 슬라이딩 해석방법을 제시하고 슬라이딩을 고려한 현수교의 시공단계별 해석을 수행하여 슬라이딩을 고려하지 않은 해석결과와 차이를 분석하였다. 슬라이딩을 고려한 해석을 통해 얻어진 결과는 구조물에 불리한 응답을 나타낼 수 있으므로 주케이블과 새들 사이의 슬라이딩을 고려한 해석은 필수적이다. 또한 본 연구의 슬라이딩 해석방법 및 해석결과는 이후 현수교의 설계와 시공시의 참고자료로 활용될 수 있다.