• Title/Summary/Keyword: 철도건설공사

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The Spill-over Effects of Domestic Production of Light Rail Transit (경량전철 국산화의 경제적 파급효과)

  • Lee, Yeon-Ho;Rhee, Young-Seop;Cho, Taek-Hee
    • Journal of the Korean Society for Railway
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    • v.11 no.4
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    • pp.424-432
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    • 2008
  • This paper presents theoretical explanations about the spill-over effects of domestic production of light rail transit and empirically investigates its effects on output, value-added and employment in the Korean economy. We distinguish net gains of domestic production from gross effects that bring about whether localized or imported cars are used. The input-output analysis is employed to fully capture the interaction among various industries involved. The empirical results reveal that net gains of domestic production such as import substitution, improvement of trade balances, and increase in output, value-added and employment are enormous. The cost reduction in construction, E&M systems, cars, management, and tariff and transportation is also significant.

Damage Cause Analysis of Concrete Sleepers for Sharp Curved Track on Urban Railway Bridge (도시철도 교량상 급곡선 자갈궤도용 콘크리트침목 손상원인 분석)

  • Choi, Jung-Youl;Shin, Tae-Hyoung;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.3
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    • pp.517-522
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    • 2021
  • In this study, the causes of damage to the concrete sleepers in a ballast track with under sleeper pads attached to the base of the sleepers installed in the sharp curved track(R=180m) of the urban railway bridge were analyzed. The damage types of concrete sleepers were investigated, and the correlation with track irregularity was reviewed. Also, stress generated in the concrete sleeper was reviewed through structural analysis. As a result, most of the cracks of the sleepers occurred in the section with severe track irregularity. In addition, as a result of the analysis, the stress generated in the track components and the sleepers was found to be reduce in the fastening system using the 4-anchor.

Analysis of Crack characteristic on Concrete Cover for Subway Box Structure Due to Reinforcement Corrosion (철근부식으로 인한 지하철 박스구조물의 콘크리트 피복층 균열특성 분석)

  • Choi, Jung-Youl;Shin, Dong-Sub;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.6
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    • pp.727-732
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    • 2022
  • Applying the calculated cross-sectional reduction due to the corroded rebar investigated in the field to the numerical analysis model, the damage pattern and delamination of concrete in the field showed a tendency relatively similar to the numerical analysis results. It was analyzed that when the expansion pressure due to corrosion of the reinforcing bar is greater than the tensile stress of the concrete, cracks are generated and the concrete cover can be fracture. As a result of this study, the correlation between the corrosion rate of reinforcing bars and the crack occurrence of the concrete cover of the subway box structure was verified based on the numerical analysis and field test results. To prevent rebar corrosion, the corrosion rate can be reduced by applying rust prevention to the reinforcing bar and changing the material. In the case of exposed to a corrosive environment, the tensile strength of the concrete is improved by adjusting the concrete compressive strength to secure durability against the expansion pressure caused by the corroded rebar.

Evaluation of Sleeper Supporting Condition for Railway Ballasted Track using Modal Test Technique (모달시험기법을 이용한 자갈궤도의 침목지지조건평가)

  • Jung-Youl Choi;Tae-Jung Yoon;Jee-Seung Chung
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.4
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    • pp.537-542
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    • 2023
  • Recently, deformation of operating railway structures has occurred due to adjacent excavation works such as new structures and utility tunnel expansion concentrated around downtown areas. However, most of them are focused on structural review, repair and reinforcement of structures. A review of the Track is insufficient. In particular, in the case of the gravel track on the earthwork subgrade, the subgrade and the ballast are not solidified. A slight level of deformation can cause ballast relaxation. Sleeper support conditions may lead to unstable conditions. Sufficient safety must be ensured. In addition, it is a track type with a high risk of train derailment due to unstable support conditions. In this study, the correlation between the deformation characteristics of gravel tracks and track support performance according to subgrade deformation is experimentally and analytically verified. In addition, an evaluation technique that can evaluate the condition of the gravel track and the track support stiffness is presented.

A Study on the Construction Work to Reduce Vibration Effect to the Structure (건축물에 영향을 미치는 열차하중에 대한 방진공사에 관한 연구)

  • 김상용;윤지언;박태하;강경인
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2004.05a
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    • pp.27-32
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    • 2004
  • Recently, the expansion of social infrastructures and urban redevelopment, the construction works have been a rapidly increase. The subway's noise and vibration are on a continuously increasing status in its importance as by the industrial and cultural development process. Nevertheless, in our country, adequate alternative idea for the construction noise and vibration are not yet established. In this point, the purpose of this study is to know the vibration effect to the structure. This study was used to determine the standard of vibration and the way of losing vibration. The case of construction site is a good example. The data of this study was obtained by a construction company in Korea. Vibration effect could cause structural problems and affect human mental state. The results of this study are as follows; check the vibrating point, determine the suitable limit of vibration, make a good plan and construction.

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A Study on Safety Accidents at Construction Work Sites of Railway (철도 건설공사 현장의 안전사고에 관한 연구)

  • Bang, Myung-Seok;Choi, Soo-Hwan
    • Journal of the Korean Society of Safety
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    • v.25 no.5
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    • pp.33-38
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    • 2010
  • Railway is one of popular transportation systems. Due to the safety and in time, the transportation by train is preferred to the others for a long time. However, accidents under railway construction get more serious problems than in case of the other system, because it is the largest mass transportation system. Especially, the railway construction is composed of different kinds of construction works such as civil, architect, electric and mechanic. It is closely/complicatedly connected with various workers, large machines and facilities, regulations etc. In this study the data on safety accidents are corrected during 6 years(2004~2009) and analyzed by time(year, month, week, day, a.m or p.m), place, field, type etc. Results shows that there exists remakable trends on accidents, so efficient treatments should be prepared considering this trend.

A Study on the Accuracy Comparison of Object Detection Algorithms for 360° Camera Images for BIM Model Utilization (BIM 모델 활용을 위한 360° 카메라 이미지의 객체 탐지 알고리즘 정확성 비교 연구)

  • Hyun-Chul Joo;Ju-Hyeong Lee;Jong-Won Lim;Jae-Hee Lee;Leen-Seok Kang
    • Land and Housing Review
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    • v.14 no.3
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    • pp.145-155
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    • 2023
  • Recently, with the widespread adoption of Building Information Modeling (BIM) technology in the construction industry, various object detection algorithms have been used to verify errors between 3D models and actual construction elements. Since the characteristics of objects vary depending on the type of construction facility, such as buildings, bridges, and tunnels, appropriate methods for object detection technology need to be employed. Additionally, for object detection, initial object images are required, and to obtain these, various methods, such as drones and smartphones, can be used for image acquisition. The study uses a 360° camera optimized for internal tunnel imaging to capture initial images of the tunnel structures of railway and road facilities. Various object detection methodologies including the YOLO, SSD, and R-CNN algorithms are applied to detect actual objects from the captured images. And the Faster R-CNN algorithm had a higher recognition rate and mAP value than the SSD and YOLO v5 algorithms, and the difference between the minimum and maximum values of the recognition rates was small, showing equal detection ability. Considering the increasing adoption of BIM in current railway and road construction projects, this research highlights the potential utilization of 360° cameras and object detection methodologies for tunnel facility sections, aiming to expand their application in maintenance.

Development of 4D System based on New Methodology for Visualizing Construction Schedule Data for Civil Engineering Projects (토목시설물 공사관리 시각화를 취한 4D시스템 적용방안)

  • Kang, Leen Seok;Jee, Sang Bok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.1D
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    • pp.95-103
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    • 2006
  • One of the main functions of the 4D system includes visualizing numerical schedule data in construction. The existing 4D tools have an excellent function for simulating building projects that all activities are progressed according to vertical work zone. However, it is not easy to implement all of it in the civil engineering project because the construction activities of highway and railway projects are progressed on the horizontal work zone and the 4D simulation for those projects should include earthwork objects that depend on the natural ground condition. This study suggests a new methodology for improving those limitations of 4D system for the civil engineering project and develops a new system by the suggested methodology. To verify the developed system, this study attempts to simulate 4D object for horizontal elements such as earthwork, paving work and tunneling work. The morphing and multi-texturing techniques developed in the study can be new approaches to simulate 4D object for the earthwork such as cutting and banking whose activities are progressed on the natural ground condition. The research results can be expected as a draft function for improving the application of 4D system in civil engineering projects.

A Study on the Applicability of the Crack Measurement Digital Data Graphics Program for Field Investigations of Buildings Adjacent to Construction Sites (건설 현장 인접 건물의 현장 조사를 위한 균열 측정 디지털 데이터 그래픽 프로그램 적용 가능성에 관한 연구)

  • Ui-In Jung;Bong-Joo Kim
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.12 no.1
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    • pp.63-71
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    • 2024
  • Through the development of construction technology, various construction projects such as redevelopment projects, undergrounding of roads, expansion of subways, and metro railways are being carried out. However, this has led to an increase in the number of construction projects in existing urban centers and neighborhoods, resulting in an increase in the number of damages and disputes between neighboring buildings and residents, as well as an increase in safety accidents due to the aging of existing buildings. In this study, digital data was applied to a graphics program to objectify the progress of cracks by comparing the creation of cracks and the increase in length and width through photographic images and presenting the degree of cracks numerically. Through the application of the program, the error caused by the subjective judgment of crack change, which was mentioned as a shortcoming of the existing field survey, was solved. It is expected that the program can be used universally in the building diagnosis process by improving its reliability if supplemented and improved in the process of use. As a follow-up study, it is necessary to apply the extraction algorithm of the digital graphic data program to calculate the length and width of the crack by itself without human intervention in the preprocessing work and to check the overall change of the building.

A Study on Seismic Retrofit Design of the Stabilized Piles by 1g Shaking Table Tests and Pseudo-static Analysis (1g 진동대 실험 및 등가정적해석을 이용한 억지말뚝의 사면안정 내진보강 효과 연구)

  • Han, Jin-Tae;Cho, Jong-Suck;Yoo, Min-Taek;Lee, Seung-Hyun
    • Journal of the Korean Society of Hazard Mitigation
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    • v.11 no.2
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    • pp.93-101
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    • 2011
  • Korea has about 70% of its land classified as the mountain area, which has led to cut-slope being the result of substantial road and railway construction. However, there is currently a lack of research about the seismic retrofit design of a slope, even though many earthquakes have recently occurred at home and abroad. In this study, in order to investigate the stabilizing effect of piles against sliding during an earthquake, a series of 1 g shaking table tests and pseudo-static analyses were carried out. As a result, the stabilizing effect of piles against sliding during an earthquake was verified by the 1 g shaking table tests and the most effective result from the pseudo-static analyses was that the installation of the piles on the central part of the slope, where the failure surface included piles unlike the lower part and upper part of the slope. Furthermore, when the pile was installed on the central part of the slope, the change of the safety factor depending on the distance between the center of two piles was evaluated.