• Structural Engineering and Mechanics
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• 제63권6호
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• pp.799-808
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• 2017

Failure of a redundant long-span bridge is often described by innumerable failure modes, which make the structural system reliability analysis become a computationally intractable work. In this paper, an innovative procedure is proposed to efficiently identify the dominant failure modes and quantify the structural reliability for a long-span bridge system. The procedure is programmed by ANSYS and MATLAB. Considering the correlation between failure paths, a new branch and bound operation criteria is applied to the traditional stage critical strength branch and bound algorithm. Computational effort can be saved by ignoring the redundant failure paths as early as possible. The reliability of dominant failure mode is computed by FORM, since the limit state function of failure mode can be expressed by the final stage critical strength. PNET method and FORM for system are suggested to be the suitable calculation method for the bridge system reliability. By applying the procedure to a CFST arch bridge, the proposed method is demonstrated suitable to the system reliability analysis for long-span bridge structure.

• 한국산업융합학회 논문집
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• 제5권3호
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• pp.239-246
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• 2002

The propose of this study is to analysis driver's behavior of traveler information. This research made an attempt to explore driver's route change behavior in the en-route stage. Model were developed for each analysis with LIMDEP software which was developed by Willams H Greene. Commuters' transportation change in before trip stage are affected by their income, travel time, and incident information and constant of this model showed their reluctance of change mode. This was resulted from the inappropriateness of traffic information to general commuters which is the main target of traffic information.

• 교육시설 논문지
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• 제25권6호
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• pp.35-44
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• 2018

The purpose of this study is to predict more accurate construction costs and to support efficient decision making in the planning and design stages of smart education facilities. The higher the error in the projected cost, the more risk a project manager takes. If the manager can predict a more accurate construction cost in the early stages of a project, he/she can secure a decision period and support a more rational decision. During the planning and design stages, there is a limited amount of variables that can be selected for the estimating model. Moreover, since the number of completed smart schools is limited, there is little data. In this study, various artificial intelligence models were used to accurately predict the construction cost in the planning and design phase with limited variables and lack of performance data. A theoretical study on an artificial neural network and deep learning was carried out. As the artificial neural network has frequent problems of overfitting, it is found that there is a problem in practical application. In order to overcome the problem, this study suggests that the improved models of Deep Neural Network and Deep Belief Network are more effective in making accurate predictions. Deep Neural Network (DNN) and Deep Belief Network (DBN) models were constructed for the prediction of construction cost. Average Error Rate and Root Mean Square Error (RMSE) were calculated to compare the error and accuracy of those models. This study proposes a cost prediction model that can be used practically in the planning and design stages.

• Computers and Concrete
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• 제6권2호
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• pp.167-185
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• 2009

Reinforced concrete floors constructed between movement restraints often crack seriously due to shrinkage after completion. One common mitigation measure is to construct the concrete floors in stages to allow part of the shrinkage movement to take place before completion. However, shrinkage movement analysis of concrete floors constructed in stages is quite cumbersome, as the structural configuration changes during construction, thus necessitating reanalysis of the partially completed structure at each stage. Herein, a finite element method for shrinkage movement analysis of concrete floors constructed in stages is developed. It analyses the whole structure, including the completed and uncompleted portions, at all stages. The same mesh is used all the time and therefore re-meshing and location matching are no longer necessary. This is achieved by giving negligibly small stiffness to the uncompleted portions, which in reality do not exist yet. In the analysis, the locked-in strains due to increase in elastic modulus as the concrete hardens and the creep of the hardened concrete are taken into account. Most important of all, this method would enable fully automatic shrinkage movement analysis for the purpose of construction control.

• 한국건설관리학회논문집
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• 제11권5호
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• pp.3-14
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• 2010

본 연구는 EPC LSTK 프로젝트의 계획단계에서 계약자가 수행하는 타당성 분석사례들을 조사 및 분석하고, 이에 대한 문제점 및 개선방안 제시를 위하여 수행되었다. 이를 위하여 GCC 국가를 대상으로 한 5개의 타당성분석에 대한 사례를 조사하고 이를 분석하였다. 상기와 같은 목적과 방법에 따라 진행된 본 연구의 결과를 요약하면 다음과 같다. 1) 타당성 분석시 고려변수 등에 대한 영향요인 분석 미흡으로 원가상승, 공기지연 초래 및 품질저하의 문제점이 존재하는 것으로 분석되었다. 2) 상기의 문제점을 바탕으로 원가상승에 대한 문제, 공기지연에 대한 문제, 품질저하의 문제에 대해 타당성 분석 차원의 개선방안을 제시하였다. 3) 해외 플랜트 공사에 있어 상기에서 분석한 문제점 및 개선방안을 준용할 수 있는 사업 타당성 분석 프로세스를 단계 별로 제시하였다.

• 한국안전학회지
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• 제21권3호
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• pp.59-66
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• 2006

Injury Ratio Survey Regulations(IRS) was introduced to the construction industry in the Republic of Korea since 1992 and brought positive effect on occupational accidents reduction. There were tremendous decrease of injury ratios and enforcing of contractors' safety organizations from the beginning of IRS. In spite of these positive results, there were some negative effects such as contractors' shrinking injury reports to keep good injury ratios since these figures had a great impact on pre-qualification stage of bidding when general contractors were competing for new construction projects. Thus, this study aims to devote on lessening construction injury and elimination of above negative impacts through the quantitative statistic analysis of the effectiveness on the occupational accidents prevention of IRS. According to this assessment, there were decrease of from 6.37% to 44.34% in the accident ratios compared to those of non-IRS groups and decrease of from 3.32% to 83.51 % in the accident ratios compared to those of general industry including the unreported accidents.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.242-243
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• 2010

The cooling system, including a fan is a one of the major sources to generate the radiated noise of construction equipment. Therefore, it is required to reduce the flow noise induced by a fan in order to reduce the noise level. In this study, we made an engine room model to carry out a variety of experiments. And then, the flow noise analysis technique using the CFD code was applied to the cooling system of construction equipment. These analyses results agree well with the measurement results. These results make it possible to understand the flow noise characteristics and to design the low noise cooling system in the design stage.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.271-272
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• 2013

The Korean nuclear industry acquired technology for each construction stage including engineering, procurement, construction and commissioning from advanced nuclear countries. While the levels of technology and quality have greatly improved, the same cannot be said for the level of project management. In particular, the level of project performance measurement and forecasting project risk still remain at the single project management level. Thus, this paper reviewed the concept of the EVMS method and requirement for the system. The adoption of the EVMS, an advanced project management method, can enable efficient management of project risks and promote an adequate environment for project implementation.

• Computers and Concrete
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• 제24권2호
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• pp.173-183
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• 2019

This study presents experimental and numerical results of prestressed concrete composite beams with different casting and stressing sequence. The beams were tested under three-point bending and it was found that prestressed concrete composite beams could not achieve monolith behavior due to interface slippage between two layers. The initial stress distribution due to different construction sequence has little effect on the maximum load of composite beams. The multi-step FE analyses could simulate different casting and stressing sequence thus correctly capturing the initial stress distribution induced by staged construction. Three contact algorithms were considered for interaction between concrete layers in the FE models namely tie constraint, cohesive contact and surface-to-surface contact. It was found that both cohesive contact and surface-to-surface contact could simulate the interface slip even though each algorithm considers different shear transfer mechanism. The use of surface-to-surface contact for beams with more than 2 layers of concrete is not recommended as it underestimates the maximum load in this study.

• 한국건축시공학회지
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• 제17권5호
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• pp.453-463
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• 2017

건물의 고층화와 규모의 증가로 인해 프로젝트 설계단계에서의 시공성을 반영한 엔지니어링 기술의 중요성이 점점 커지고 있다. 특히, 설계단계에서의 가설작업을 위한 설비, 장비 및 공법과 관련된 엔지니어링 기술적용의 노력은 시공성 및 프로젝트 성과 향상에 크게 기여할 수 있다. 이에 본 연구에서는 고층 건축공사의 시공성 향상을 위하여 가설공사를 중심으로 설계단계에 요구되는 시공엔지니어링 업무를 도출하고자 하였다. 우선, 문헌고찰과 전문가 집단면접을 통해 27개의 예비 업무를 도출하였으며, 그 후 설문조사를 통하여 각 업무의 필요성 및 중요도를 분석하였다. 분석 결과, 골조공사 및 양중장비 계획과 관련된 대부분의 업무가 상대적으로 중요한 것으로 분석되었다. 마지막으로 요인분석을 통해 21개의 엔지니어링 업무를 선정하였으며, 이들 업무는 크게 1)골조공사 및 측량/동선계획, 2)양중 및 콘크리트 압송계획, 3)공간구획계획, 4)용수계획, 5)가설건물 및 전력/조명계획의 5개 요인으로 분류되었다. 본 연구의 결과는 설계단계에서 시공엔지니어링 업무를 효과적으로 반영할 수 있는 프로세스 수립을 위한 기초 자료로 활용될 수 있을 것이다.