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온도 효과를 이용한 일부 타정식 사장교의 키-세그먼트 폐합법
원정훈,윤지현,조광일,김상효,Won, Jeong Hun,Yoon, Ji Hyun,Cho, Kwang Il,Kim, Sang Hyo 한국강구조학회 2008 韓國鋼構造學會 論文集 Vol.20 No.1
본 연구에서는 FCM 공법으로 건설되는 사장교의 최종 시공 단계인 키-세그먼트 폐합 방법으로 기존의 set-back과 reset-back 방법 대신 온도 효과를 이용한 폐합방법을 제안하여, 이를 일부 타정식 사장교에 적용하였다. 제안된 방법은 키-세그먼트 폐합 전 캔틸레버 상태인 교량 시스템의 중앙 경간부 거더 내부에 인위적인 가열 작업을 하여 거더를 신장시킨 후 키-세그먼트 폐합 후 연속교 상태에서 가열을 제거하는 방법으로, 가열 작업과 가열 제거 작업시의 시스템 변화를 이용하여 교량 시스템에 인위적인 부재력을 발생시키는 방법이다. 기존의 자정식 사장교를 일부 타정식 사장교로 변경 후 시공단계 해석을 수행한 결과, 인위적으로 발생된 부재력은 일부 타정식 사장교의 구조 시스템 특징에 부합하여 거더부의 압축력을 감소시키므로 제안된 방법은 일부 타정식 사장교에 효과적으로 적용될 수 있는 것으로 판단된다. study proposes a new key-segment closing method using thermal effect as a substitute to the process of set-back and reset-back for the FCM construction of a partially earth-anchored cable-stayed bridge. The proposed method is to artificially heat up the inside of girders located in the main span before closing the key-segment in a cantilever state. Then, the heat is removed after finishing the closure in a continuous bridge state. Using the changes in boundary conditions and structural systems, the proposed method can generate new member forces that reflect the advantage of the partially earth-anchored cable system. From the construction sequence analysis, it is found that the proposed method increases the efficiency of a partially earth-anchored cable-stayed bridge by reducing the compressive axial forces on the girders.
스마트건설안전 비용의 안전관리계획서 계상 현황 분석을 통한 활성화 방안 연구
원정훈,장남권,유지영,Won, Jeong-Hun,Jang, Nam Gwon,Yu, Ji Young 한국안전학회 2022 한국안전학회지 Vol.37 No.3
This study analyzed the smart construction safety cost included in safety management plans that are approved before construction. Specifically, it refers to the cost incurred in constructing and operating a safety management system using wireless communication and facilities. Based on the obtained statistical results, an activation policy for the inclusion of the smart construction safety cost in building safety management plans was proposed. The smart construction safety cost must be included in the safety management cost; notably, this is mandated by the Construction Technology Promotion Act. However, there are some problems with the inclusion of smart construction safety costs. To analyze the problems encountered when calculating the smart construction safety cost and including it in safety management plans, in this study, statistical analysis was performed using the data of 1,334 safety management plans received at the Construction Safety Management Integrated Information (CSI) from June to August 2021. The results show that only 50.7% of the safety management plans included the smart construction safety cost although the current law mandates 100% inclusion of these costs. Thus, it is apparent that the smart construction safety costs are only included in a low proportion of sites. In addition, the calculated smart construction safety costs were shown to have a small correlation with the construction cost; moreover, they appeared to be distributed at a constant cost level. In this context, it is believed that perfunctory cost calculations were performed at most sites since the effect of the construction cost on the smart construction safety cost was negligible. Therefore, it is necessary to improve the inclusion of smart construction safety costs by strengthening the authorization process of the approval institute of safety management plans. In addition, institutional support, such as guidelines that promote the calculation and inclusion of appropriate smart construction safety costs according to the characteristics of sites, are needed.
장경간 사장교에 적용된 일부타정식 케이블 시스템의지진하중과 풍하중 안전성 향상 효과 분석
원정훈 ( Jeong-hun Won ),이형도 ( Hyung Do Lee ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.4
This study investigates effects of partially earth anchored cable system on the structural safety for a long-span cable-stayed bridge under dynamic loads such as seismic and wind load. For a three span cable-stayed bridge with a main span length of 810 m, two models are analyzed and compared; one is a bridge model with a self anchored cable system, the other is a bridge model with a partially earth anchored cable system. By performing multi-mode spectrum analysis for a prescribed seismic load and multi-mode buffeting analysis for a fluctuating wind component, the structural response of two models are compared. From results, the partially earth anchored cable system reduce the maximum pylon moment by 66% since earth anchored cables affect the natural frequencies of girder vertical modes and pylon longitudinal modes. In addition, the girder axial forces are decreased, specially the decrement of the axial force is large in seismic load, while girder moment is slightly increased. Thus, the partially earth anchored cable system is effective system not only on reduction of girder axial forces but also improvement of structural safety of a cable-stayed bridge under dynamic loads such as seismic and wind loads.
시스템 동바리 수직재와 수평재 연결부의 휨강도와 회전 강성 평가
원정훈 ( Jeong-hun Won ),이형도 ( Hyung Do Lee ),최명기 ( Myeong-ki Choi ),박만철 ( Man Cheol Park ) 한국안전학회(구 한국산업안전학회) 2018 한국안전학회지 Vol.33 No.4
This study examined the maximum resistant moment and nonlinear rotational stiffness of wedge joint between the vertical and horizontal members of system supports. To examine the maximum resistant moment and propose the nonlinear rotation stiffness of wedge joint, 6 specimens were tested and additional 3 specimens, where the horizontal member was welded to the vertical member, were tested to compare the moment capacity of wedge joints. The average maximum moment in the tested wedge joint was 1.183 kNm which represented about 70 % of the maximum moment developed in the welded specimens. And, as simulating nonlinear rotational stiffness of the wedge joint, a tri-linear model was suggested. The rotational stiffness was estimated as 23.095 kNm/rad in first stage, 7.945 kNm/rad in second stage, and 3.073 kNm/rad in third stage. For the failure mode, the specimen with the wedge joint showed the failure of joint between vertical and horizontal members. However, the specimen with welded joint represented the yielding of horizontal members.
건설공사 발주자의 안전보건관리 책임 부여에 대한 공사 참여자 인식 조사
원정훈 ( Jeong Hun Won ),박형근 ( Hyung Keun Park ),임세종 ( Se Jong Lim ),박용규 ( Yong Kyu Park ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.5
This study investigated the recognition difference among construction work participants for the assignment of the safety and health management responsibility to a client by survey. Recently, there were some studies for the client``s responsibility and duty and they suggested the client-initiative safety and health management system in order to prevent construction accidents. To supplement the existed studies, this study surveyed various construction participants such as clients, safety managers, construction managers, supervisors, others. The clients and construction managers considered the contractor as most important person to prevent construction accidents, but the safety managers and supervisors considered the client. For the opinion that the assignment of the safety and health management duty to a client is helpful, safety managers were agreed with the most. However, the clients showed the lowest agreement. The reasons that the negative opinion for the assignment of client``s the safety and health management were different between clients and other construction parties. Since, clients showed large difference to other construction participants for the recognition of works`` safety and health, the education about the works`` safety and health management should be continuously performed for clients to have correct recognition for works`` safety and health.
일부타정식 케이블 시스템 장경간 사장교의시공 중 동적 안전성 분석
원정훈 ( Jeong-hun Won ),김경윤 ( Gyeoung Yun Kim ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.4
The effect of a partially earth anchored cable system on the structural safety of a long span cable-stayed bridge under seismic and wind loads are examined during construction process. By assuming the FCM (free cantilever method) construction stages with structural vulnerability, a multi-mode spectral analysis and a multi-mode buffeting analysis are performed for specific seismic load and wind load, respectively. Results show that the wind load dominates the structural safety of a cable-stayed bridge during construction. And, the application of a partially earth anchored cable system can enhance structural safety under wind load since the maximum pylon moment in the model with partially earth anchored cable system is reduced by 49% under wind load. In contrast, the maximum pylon moment occurred by seismic load is only decreased by 8%.