• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.888-895
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• 2009

Compaction is a process of increasing soil density using physical energy. It is intended to improve the strength and stiffness of soil. In embankment, degree of compaction affects the construction time, money, also method of soil improvement. In large scale embankment project, difficulties of embankment should change due to uncertainty of settlement. So it is very important to predict the final settlement and factor of safety induced by embankment. In many construction site, there are primarily design of high embankment using in-situ soil. Therefore numerical analyses are necessary for valid evaluation of the settlement prediction. But due to the construction cost and schedule, there were lacking in properties of soil and also limited number of in-situ test were performed. So we proposed the method that can easily estimate the proper soil parameters and suggest the proper method of numerical analysis. From this, two-dimensional finite-difference numerical analysis was conducted to investigate the settlement and factor of safety induced by embankment with various case of compaction rate and embankment height.

• 대한안전경영과학회지
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• 제16권4호
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• pp.31-40
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• 2014

While Korea had achieved radical growth of construction industry, it also had accumulated problems in material, human and economical loss due to its low quality of safety level. Therefore, not only enterprises but also the nation is putting in a great deal of efforts for construction safety. However, its effect is not satisfiable. This research aims for change of construction cite by introduction of professional Safety Patrol Management System(SPMS) and consideration of its necessity. To consideration of its necessity, we compared and anaylzed average numbers of indicated dangers and safety accident incidences in each construction cites and we researched changes in worker's safety sense. It will establish the suitable design standards and suggest the basic database for estimating disaster and accident ratio.

• Steel and Composite Structures
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• 제22권3호
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• pp.647-662
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• 2016

This study aims to monitor the variation of modal frequencies of steel buildings during their construction sequence. In this respect, construction of a steel building is followed by vibration based measurements. The monitored building is a three-story educational building within a building group whose structural system consists of steel moment resisting steel frames and eccentric braces. Five different acceleration measurements in two perpendicular directions are taken on five different construction stages, starting from the erection of the columns and beams ending with the completion of the construction. The recorded measurements are transferred into frequency domain and the dominant frequencies for each case have been determined. The change in the dominant frequencies is evaluated with the existing construction stages and performed constructional works between the stages. The last measurement, performed on the building in service, revealed the first two dominant frequencies as mutual in X and Y direction, showing that these dynamic modes are torsional modes. This result is investigated by numerical analysis performed with finite element model of the building constructed for design purpose. Lower frequencies and different mode shapes are determined from numerical analysis. The reason of lower frequencies is discussed and the vibration survey is extended to determine the effects of an adjacent building. The results showed that the building is in strong relation with an adjoining building in spite of a designed construction joint.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.129-136
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• 2020

Augmented reality (AR) technology assists construction workers by superimposing additional virtual information onto their real worksite environments. Ideally, this provides them with a better understanding of their tasks and hence boosts task performance. However, the additional information that AR places in users' field of view could limit their ability to understand what is going on in their surroundings and to predict how conditions may change in the near future. AR-assisted systems on construction sites could therefore expose their users to safety risks due to disturbance from the system. Hence, it is important to understand how AR-assisted systems can block users' understanding of their immediate environments, and in turn, how worksite safety in the construction industry could be improved through better design of such systems. This preliminary research conducted a laboratory experiment that simulated rebar inspection tasks and compared the situational awareness of AR users against that of subjects using traditional paper-based inspection methods, as measured by the Situation Awareness Rating Technique. Based on the results, we discuss the safety impact of head-mounted AR-assisted displays on situational awareness during construction tasks.

• 건설안전기술
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• 통권38호
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• pp.79-87
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• 2006

Formwork is a temporary structure that supports its weight and that of freshly placed concrete as well as construction live loads. In constructions site, pipe supports are usually used as shores which are consisted of the stab formwork. The strength of a pipe support is decreasing as it is frequently being used at the construction site. Among the accidents and failures that occur during concrete construction, there are many formwork failures which usually happen at the time concrete is being placed. The objective of this study is to find out the strength change of used pipe support and unused pipe supports according to aging. In this study, 2857 pipe supports were prepared. Among these pipe supports, 2337 pipe supports were lent to the construction companies free of charge. 520 pipe supports were kept on the outside. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports as well as used pipe supports was decreasing according to age, use frequency and load carrier, and the strength of used pipe supports was lower than the strength of unused pipe supports at the same age. So, the strength of used pipe supports from 191 days to present day was not satisfied the specification of KSF 8001. In this study, the strength of pipe support according to age, use frequency and load carrier was predicted using SPSS 12.0. It was known that the strength of pipe support using for 5 years was reduced to 42.8%. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the present study results will be able to provide a firm base to prevent formwork collapses.

• 한국실내디자인학회논문집
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• 제21권6호
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• pp.212-223
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• 2012

The "Eco-friendly", "Green" concepts was began around 1992 after the Rio Environmental Summit, and the need for sustainable development globally widespread. The green building certification system was began around 2000 and the concept of green building was started in the late 1990s. The green building, which welcomes a period of radical change, is for the survival of the Earth "climate change" and reducing energy consumption in building sector. In this architecture of eco-friendly concept, the green building is rapidly expanding and existing as a ecological environment preservation. Moreover, the realization of zero energy house is to mandate for new buildings in 2025. The aim of further eco-friendly is through the prior ecosystems to restore and product energy for the 9 Green Building model houses in this paper. Building in the concept of ecology is to show about change into 7R's from the 3R's. The "Reduce", "Reuse", "Recycle" consisting of "3R's" is correlated with the traditional to the present Green Building Design. U.S. NCARB (National Council of Architectural Registration Boards) change into the concept of 7R's as "Receive", "Restore", "Respect" and "Remember", added to "3R's". In this paper, the 9 Green Building model houses do not meet the criteria of 7R's. But, the Green Tomorrow of Samsung C & T Corporation meet the 6 criteria for 7R's. This company is most comfortable at low carbon Green Building model houses. Conclusionally, introduction of eco-friendly technologies and amenities for the health of human and natural community life is to advance eco-friendly construction and enhance brand value of housing. By the way, The problem of eco-friendly architecture is initial investment and maintenance. Therefore, eco-friendly architecture and government has to try solving of this difficulty.

• 토지주택연구
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• 제8권4호
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• pp.257-266
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• 2017

LH has been using ultra high strength reinforcing bars (SD500 and SD600), since 2011. Such a change requires an adjustment of the old extra rates of bar splice to reflect use of ultra high strength reinforcing bars, as these rates had been set based on SD400 bars. It is particularly difficult to calculate precisely rebar lap-splice locations for large areas, such as those in apartment buildings. This research aims to adjust the extra rates of bar splice to reflect a reasonable rate; the rebar lap-splice length is not an exact estimation, but instead, an extra rates of bar splice is set and the rebar lap-splice length is increased by 2% (D 10) - 7% (025) depending on the bar size. The subjects of this study are LH apartments undergoing frame construction. We studied the quantity estimations from the design drawings, and analyzed the settlement quantities of construction field. The results of the study revealed that, when each of the quantities are analyzed, consider adjusting the extra rates of bar splice of some rebar to 1% - 3.5%. This was caused by an overuse of reinforcing bars in onsite construction and the use of supporting bars that have not been reflected in the documents, among other reasons. Based on the results of our study, an improvement plan for the current extra rates of bar splice seems to be necessary, cutting or raising the rate depending on the analysis of the data. Through this study, we expect to contribute to the calculation of reasonable construction costs, improvements in the quality of rebar work, and improvements in the capacity of design techniques for apartment buildings.

• 한국전산구조공학회논문집
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• 제23권3호
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• pp.325-330
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• 2010

현행 토목 설계분야에서는 BIM(Building Information Modeling)기반의 3차원 객체모델의 활용이 미미한 수준이다. 본 논문에서는 철도교량의 상부구조인 PSC 박스거더에 대하여 BIM기반의 3차원 객체 모델을 구성하였으며, 모델의 기초구성은 파트(Part)모델로 되어있다. 파트(Part)모델은 여러 가지 단위 모델 중 최소 단위이며, 이것은 설계대상 구조물의 특성을 반영하여 계층구조를 가진다. 3차원 객체 모델은 설계자의 설계변경의도를 신속하게 반영할 수 있어야 한다. 실제 설계과정에서는 반복적인 설계변경이 발생할 수 있기 때문이다. 이를 위하여 설계변수를 파라미터로 구분을 하였으며 그 파라미터들은 3차원 객체모델의 정보와 연계되어 있기 때문에 설계 변경에 신속하게 대응할 수 있다. 이 연구에서 우리는 3차원객체 모델을 토목설계분야에 활용하여 얻을 수 있는 이점을 고찰하였다. 또한 PSC 박스거더의 3차원 객체 모델의 효율적인 적용방안을 제시하였다.

• 한국건설관리학회논문집
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• 제17권5호
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• pp.35-44
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• 2016

건설 프로젝트의 특성 상, 예측하기 어려운 리스크 인자에 노출되기 쉽고, 다양한 이해관계자들이 함께 동일 프로젝트를 수행하는 과정에서 발생하는 분쟁이 주요 리스크 인자로 인식된다. 다양한 분쟁은 주로 클레임 제기, 조정, 중재, 그리고 소송으로 나타나며 막대한 비용과 시간의 손실을 초래할 수 있다. 따라서 국내 건설기업의 건설 프로젝트 수행과정에서 발생하는 클레임, 분쟁의 유형과 원인을 도출하고, 각 원인의 영향도 분석을 통해 클레임, 분쟁관리에 대한 적극적인 대비가 필요하다. 본 연구는 국내 건설프로젝트에서 발생한 클레임, 분쟁 판례를 수집하여 유형과 원인에 따른 빈도와 영향도를 정량화 하고, 중요도 분석을 통해 주요 클레임 원인을 도출하였다. 도출된 주요 클레임 원인은 공사변경, 상대방의 부당한 행위, 공사 지연에 관한 클레임으로 해당 클레임 원인이 발생할 경우 클레임 비용에 대한 예측을 회귀 모형화 하였다. 주요 클레임 원인별 영향도 예측 결과 공사변경의 경우 전체공사비의 16.1%, 상대방의 부당한 행위는 전체공사비의 5.7%, 공사 지연은 전체공사비의 2.7%로 발생하는 것으로 분석되었다. 본 연구결과를 통해 국내 건설산업의 주요 클레임 요인을 도출하고, 클레임 비용을 예측함으로써 보다 적극적인 클레임 대비에 활용 될 수 있도록 하였고, 더 나아가 국내 건설기업의 프로젝트 관리 역량 평가 및 향상에 기여하고자 하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.596-601
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• 2008

This paper presents how to develop visual design tools for construction of strut-and-tie models(S (STM). STMs have shown internal force flows for dimensioning and proportioning of D-regions of reinforced concrete structures. In order to select an appropriate strut-and-tie model some interactive graphic tools are necessary to help designers compare alternatives by changing the geometry of initial STM. This study proposes to use force polygons representing the equilibrium state of STM. The change of STM dynamically shows change of force magnitudes by force polygon. Once the geometry of STM is determined the detailing design process is required in the next procedure.