• 전산구조공학
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• 제10권2호
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• pp.189-201
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• 1997

국내 보도육교의 경우, 단순한 구조형식과 공장제작에 의한 현장조립의 신속한 시공 및 유지관리상의 장점들로 인하여 표준화된 강상형 보고육교가 교통혼잡이 심한 도심지와 각종 국도상에 다수 건설되어 왔지만, 이중 상당수의 육교가 공용년수 증가와 더불어 열화손상되어 안전도 및 사용성이 매우 불량한 상태에 있다. 본 논문에서는 열화손상된 기존의 강상형 보도육교의 실제적인 안전도 및 잔존내하력을 평가하기 위하여 선진각국에서는 이미 일반화되고 있는 von Mises'조합응력항복기준에 기반을 둔 한계상태설계법에 기초하여 각 구조부위의 항복 및 좌굴에 대한 각각의 비선형 한계상태모형을 제안하고 이를 실구조물에 적용해서 안전도평가 및 신뢰성평가를 수행하여 제안된 모형의 타당성을 고찰하였다. 뿐만아니라 노후된 기존 강상형 보도육교에 대한 현장재하시험 방법과 이들 시험결과를 이용한 실용적이고 합리적인 잔존내하력 평가방법을 제안하고 각국 시방서별/설계방법별로 비교, 고찰하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제16권4호
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• pp.60-68
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• 2012

본 연구에서는 미국 뉴욕주 로체스터시 소재 강합성 데크 트러스 보도교를 대상으로 사용성을 평가하기 위한 상시진동 실험(ambient vibration test)을 수행하였고 이를 해석적 방법에 의한 결과와 비교하였다. 교량전체에 대한 상시진동실험은 수치모델 작성 시 도입되는 여러 가정들에 대한 타당성을 평가하는데 있어서 유용한 방법이며, 교량의 고유진동수나 모드형상과 같이 구조 동력학에서 중요한 구조적인 변수를 결정하는데 있어 중요한 역할을 한다. 본 연구에서는 교량의 수직방향 및 수평방향 진동 특성과 변위를 측정하기 위하여 실제 교량에서 보행자에 의해 발생하는 진동을 입력하중으로 사용하였다. 교량 구조물에 대한 모델링을 위하여 3차원 유한 요소법을 사용하여 해석을 수행하였으며, 이를 통하여 현장실험 결과와의 유효성을 입증하였다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.5-8
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• 2004

About 175 vehicular bridges and 160 pedestrian bridges in service now, worldwide, are made of composites, completely of partially. In this paper, the status of this application is briefly explained.

• International Journal of Concrete Structures and Materials
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• 제7권1호
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• pp.79-93
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• 2013

One of the biggest problems affecting bridges is the transverse cracking and deterioration of concrete bridge decks. The causes of early age cracking are primarily attributed to plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. The cracks can be influenced by material characteristics, casting sequence, formwork, climate conditions, geometry, and time dependent factors. The cracking of bridge decks not only creates unsightly aesthetic condition but also greatly reduces durability. It leads to a loss of functionality, loss of stiffness, and ultimately loss of structural safety. This investigation consists of field, laboratory, and analytical phases. The experimental and field testing investigate the early age transverse cracking of bridge decks and evaluate the use of sealant materials. The research identifies suitable materials, for crack sealing, with an ability to span cracks of various widths and to achieve performance criteria such as penetration depth, bond strength, and elongation. This paper also analytically examines the effect of a wide range of parameters on the development of cracking such as the number of spans, the span length, girder spacing, deck thickness, concrete compressive strength, dead load, hydration, temperature, shrinkage, and creep. The importance of each parameter is identified and then evaluated. Also, the AASHTO Standard Specification limits liveload deflections to L/800 for ordinary bridges and L/1000 for bridges in urban areas that are subject to pedestrian use. The deflection is found to be an important parameter to affect cracking. A set of recommendations to limit the transverse deck cracks in bridge decks is also presented.

• Computers and Concrete
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• 제24권4호
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• pp.303-311
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• 2019

The depth of superstructure is the summation of the height of girders and the thickness of the deck floor. In this study, it is aim to determine the maximum span length of girders and minimum depth of the superstructure of prestressed concrete I-girder bridge. For this purpose the superstructure of the bridge with the width of 10m and the thickness of the deck floor of 0.175m, which the girders length was changed by two meter increments between 15m and 35m, was taken into account. Twelve different girders with heights of 60, 75, 90, 100, 110, 120, 130, 140, 150, 160, 170 and 180 cm, which are frequently used in Turkey, were chosen as girder type. The analyses of the superstructure of prestressed concrete I girder bridge was conducted with I-CAD software. In the analyses AASHTO LRFD (2012) conditions were taken into account a great extent. The dead loads of the structural and non-structural elements forming the bridge superstructure, prestressing force, standard truck load, equivalent lane load and pedestrian load were taken into consideration. HL93, design truck of AASHTO and also H30S24 design truck of Turkish Code were selected as vehicular live load. The allowable concrete stress limit, the number of prestressed strands, the number of debonded strands and the deflection parameters obtained from analyses were compared with the limit values found in AASHTO LRFD (2012) to determine the suitability of the girders. At the end of the study maximum span length of girders and equation using for calculation for minimum depth of the superstructure of prestressed concrete I-girder bridge were proposed.

• 한국공간구조학회논문집
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• 제12권4호
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• pp.99-108
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• 2012

In recently, sky-bridge are often applied to high-rised adjacent buildings for pedestrian bridge. the seisnic response control of adjacent buildings have been studied and magneto-rheological(MR) fluid dampers have been applied to seismic response control. In this study, vibration control effect of the MR damper connected adjacent buildings has been investigated. Adjacent building structures with different natural frequencies were used as example structures. Two typed of control methods, displacement based or velocity based, are applied to determinate control force of MR damper. In this numerical analysis, it has been shown that displacement-based control algorithm is more effective than velocity-based control algorithm for seismic response control of adjacent buildings. And, when displacement-based control method is applied to control of adjacent buildings, the control of building occurred large displacement is more efficient in reducing the seismic response.

• 한국BIM학회 논문집
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• 제5권4호
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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.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.197-202
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• 2008

한국토지공사는 주거, 금융센터, 리조트 시설, 쇼핑 몰, 관광과 스포츠 시설을 포함하는 대규모 단지계획으로서 인천 청라지구를 계획하고 있다. 대규모 단지 (1780만$m^2$)중에 하나가 건설 중이다. 전체지역을 6개의 지역으로 구분하고 6개의 보석 명칭(크리스탈, 샤파이어, 루비, 에머랄드, 자드, 진주, 다이아몬드)들을 부여하고 있다. 한국토지공사는 3개의 주거 단지에 그 지역을 대표할 수 있는 다양하고 특별한 형태와 구조 시스템을 요구하였다. 본인은 이러한 구조형태의 인도교를 소개하고자 한다. 4개의 사장교 뿐만 아니라, 아치교과 트러스교들이 계획되었다.

• KIEAE Journal
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• 제15권4호
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• pp.53-60
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• 2015

Purpose: Subway in Seoul, Korea is an important urban mass transportation system as it carries more than 4 million people a day. To support this important mission, subway entrances were designed and installed to maximize accessibility to the stations. However, a uniform plan by the national government guided quantity and layout of the subway entrances. Therefore, the plan did not consider unique characteristics of each station area and reorganization of the subway entrance system is required to improve pedestrian environment. Method: This study grouped the subway entrances into specific patterns to propose reorganizing schemes. The authors conducted field surveys, examined case studies and proposed an entrance reorganizing plan for each type. Result: The study recommends subway entrances be installed inside adjacent building when large commercial or office complexes are nearby. The authors proposed installing a bridge connecting the stations and adjacent buildings for elevated entrances. This would be only possible when there are commercial or office facilities nearby with enough floor space. The study summarizes the pros and cons of each solution. To translate our proposals into realities, various incentives should be given to building or land owners. This study made suggestions as to which kinds of incentives exist and be effective in a range of situations.

• Smart Structures and Systems
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• 제24권5호
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• pp.617-630
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• 2019

Currently most of the vision-based structural identification research focus either on structural input (vehicle location) estimation or on structural output (structural displacement and strain responses) estimation. The structural condition assessment at global level just with the vision-based structural output cannot give a normalized response irrespective of the type and/or load configurations of the vehicles. Combining the vision-based structural input and the structural output from non-contact sensors overcomes the disadvantage given above, while reducing cost, time, labor force including cable wiring work. In conventional traffic monitoring, sometimes traffic closure is essential for bridge structures, which may cause other severe problems such as traffic jams and accidents. In this study, a completely non-contact structural identification system is proposed, and the system mainly targets the identification of bridge unit influence line (UIL) under operational traffic. Both the structural input (vehicle location information) and output (displacement responses) are obtained by only using cameras and computer vision techniques. Multiple cameras are synchronized by audio signal pattern recognition. The proposed system is verified with a laboratory experiment on a scaled bridge model under a small moving truck load and a field application on a footbridge on campus under a moving golf cart load. The UILs are successfully identified in both bridge cases. The pedestrian loads are also estimated with the extracted UIL and the predicted weights of pedestrians are observed to be in acceptable ranges.