• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.461-464
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• 2004

External prestressing method is the most papular method to strengthen concrete structures. The key parts of external prestressing method is an anchoring device which holds the prestressing cables. The most popular anchoring devices is an end bearing type, which has to be welded at site to assamble the anchor. The welding at site has a significant Quality problem. In this paper, new anchoring system has been developed, which needs no site welding. A design method for the new anchor has been proposed and developed to optimize the anchoring system. The developed anchors are very efficient, small, and compact, which have two types, one for abutment section and the other one for pier section. The anchors are expected to be used very widely, because of its convinience.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.225-228
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• 2006

Fast construction of bridge structures is a new trend of bridge design. Accelerated bridge construction includes the construction of superstructures and substructures. In order to reduce the construction time for substructures, precast prestressed bridge piers are increasingly applied in other countries. One of the main concern in the design of precast piers is the determination of the axial prestress forces. The behavior of the piers should be investigated under service loadings and ultimate conditions. In this paper, the magnitude of prestress is calculated to control the stress at the joint of precast piers. Considering long-term behavior of prestressed piers, P-M diagrams for precast piers are obtained to verify the ultimate behavior of the piers. Based on these studies, precast piers are applied to the light-railway bridge piers.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.213-214
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• 2013

Recently, modular construction has been begun to introduce actively for improvment of productivity in the construction industry. By the way, the construction technology is being IT through BIM. This is why modular construction needs BIM technology. In this study, we analyze the problems in the current modular construction at factory production stage. The way to extract 3D shop drawings using BIM is suggested to solve this problem.

• Journal of KIBIM
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• v.5 no.4
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• pp.47-52
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• 2015

This paper presents a case study using Building Information Modeling (BIM) for planning, simulating, and implementing complex site logistics in a headquarter office building construction project in Silver Spring, MD. As part of the project a prefabricated 92ft structural tube steel pedestrian connector bridge was installed between two adjacent buildings in the city of Silver Spring, MD. There were multiple significant challenges to deliver, offload, prepare, and install the connector bridge safely, on time, and with the minimum disturbances to the neighbors. BIM was of the foremost importance to visualize, simulate, analyze, improve, and communicate the site logistics plan from delivery to installation of the connector bridge. As a result of the effort, GC of the project was able to prepare a highly detailed plan, communicate it effectively to all stakeholders, and flawlessly execute the work as planned. This case study would provide a useful reference for contractors who are seeking a better planning method that enables generation of more accurate, implementable, optimized plans for complex site logistics.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2256-2258
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• 2005

우리는 기존의 현장몰드방식의 TMJ(Tape Molded Joint)와 부품조립방식 의 PJ(Prefabricated Joint) 보다 조립시간과 숙련도가 덜 필요한 고무몰드접속함을 탄성 및 우수한 절연특성을 가진 silicone 고무를 사용하여 조립공정과 절연특성, 탄성특성, 계면특성, 열적 특성 등을 연구하여 개발에 성공하였다. 고무 몰드 접속함은 실리콘 재료의 우수한 탄성에 의해 동일 케이블의 다양한 size에 적용이 가능하다.

• Journal of the Korea Institute of Building Construction
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• v.3 no.2
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• pp.111-118
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• 2003

Steel frame construction is divided into subsidiary materials with column, beam, girder and bracing. After these are processed in factory for using installing in construction field. These prefabricated furniture is very important in accordance with design drawing about processing and prefabricating. In the case of design process using information transmission in blueprint, omission of material number, processing measure and finishing material, or discordance of each structure drawing and selecting incongruent structural material generated an error in the process of design. These error caused delaying time and increasing cost and increasing safety accident in the steel-structure work operating process. therefore, design process should consider problem of operating process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.108-111
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• 2003

Currently, molecular devices are reported utilizing active self-assembled monolayers containing the nitro group as the active component, which has active redox centers[1]. We confirm the electrical properties of 4,4-di(ethynylphenyl)-2'-nitro-1-benzenethiolate. To deposit the SAM layer onto gold electrode, we transfer the prefabricated Au(111) substrates into a 1mM self-assembly molecules in THF solution. Au(111) substrates were prepared by ion beam sputtering method of gold onto the silicon wafer. As a result, we measured current-voltage curve using ultra high vacuum scanning tunneling microscopy (UHV STM), I-V curve also clearly shows several current peaks between the negative bias region (-0.3958V) and the positive bias region (0.4658V), respectively.

• Computers and Concrete
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• v.20 no.6
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• pp.689-704
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• 2017

The paper presents experimental and numerical investigations of prefabricated composite structural building reinforced concrete slabs with the insulating material for a residential building construction. The building slabs were composed of concrete and expanded polystyrene. In experiments, the slabs in the full-scale 1:1 were subjected to vertical concentrated loads and failed along a diagonal shear crack. The experiments were numerically evaluated using the finite element method based on two different constitutive continuum models for concrete. First, an elasto-plastic model with the Drucker-Prager criterion defined in compression and with the Rankine criterion defined in tension was used. Second, a coupled elasto-plastic-damage formulation based on the strain equivalence hypothesis was used. In order to describe strain localization in concrete, both models were enhanced in the softening regime by a characteristic length of micro-structure by means of a non-local theory. Attention was paid to the formation of critical diagonal shear crack which was a failure precursor.

• Computers and Concrete
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• v.23 no.3
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• pp.203-215
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• 2019

Precast reinforced concrete structure (PRCS) consists of prefabricated members assembled at worksites and has more connections limitations in comparison with the equivalent in-situ reinforced concrete structure (IRCS). As a result of these limitations, PRCSs have less ductility in comparison with IRCSs. Recent studies indicate that the most noticeable failure in PRCSs have occurred in their connection zone. The objective of this study is introducing a type of precast beam-to-column connection (PBC) which in spite of being simple is of the same efficiency and performance as in-situ beam-to-column connection (IBC). To achieve this, the performance of proposed new PBC at exterior joint of a four story PRCS was analyzed by pseudo dynamic analysis and compared with that of IBC in equivalent IRCS. Results indicated that the proposed connection has even better performance in terms of strength, energy dissipation and stiffness, than that of IBC.

• Journal of KIBIM
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• v.10 no.4
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• pp.40-49
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• 2020

This report describes the development of a program that can be linked to an alignment and extracts related information using a prefab structured digital engineering model. The subject bridge was set as a straight alignment, the Superstructure type as Precast girder and the Substructure type as Precast pier and Cast-in-situ Abutment. We identified the variables required to create a digital engineering model and reviewed them to create the digital engineering model by entering them as numerical values in the program. In addition, it is configured so that the variables linked to the alignment can be entered numerically. The quantity takeoff can be calculated when the design is complete. The purpose of the program development presented in this report is to enable the designers to select the optimal alternative by designing a bridge that best fits their current situation, extracting the relevant information and then by providing it to the manufacturer and construction company.