• Title/Summary/Keyword: bridges construction

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Construction of the Busan-Geoje Fixed Links Immersed tunnel (기획특집 - 거가대교 침매터널의 시공)

  • Cho, Bong-Hyun
    • Journal of the Korean Professional Engineers Association
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    • v.43 no.2
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    • pp.34-38
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    • 2010
  • The Busan-Geoje Fixed Link is an 8.2 km long motorway connecting Busan to the island of Geoje where the Korean big two shipbuilding yard locate on. This motorway includes a 3,300m immersed tunnel which is one of the longest immersed tunnel in the world and two cablestayed bridges each of 2km in length. The site locates in a exposed offshore, which is subjected to strong winds, large swell waves and strong tidal currents. These conditions together with the tunnel being at a deepest immersed tunnel ever built and the foundation condition is consisting of a very soft, normally to slightly over consolidated marine clay, makes the project unique and one of the most challenging immersed tunnels ever built.

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Effect of Acid Fog on Rust Formation and Fatigue Strength of Weathering Steel (산성안개가 내후성강재의 녹형성 및 피로강도에 미치는 영향)

  • Kim, Min-Gun;Ku, Eun-hoi
    • Journal of Industrial Technology
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    • v.22 no.B
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    • pp.13-20
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    • 2002
  • The purpose of this study is to investigate the effect of acid fog on the rust formation behavior of weathering steel (SMA50) which is used in uncoated bridges. Weathering steel didn't form the passive film under the environment of acid fog(pH5,6), whereas the environment of distilled water formed the protective oxide film. Therefore, the construction of weathering steel under the environment extremely exposed to SOx and NOx which are the main compositions of acid fog is not adequate. Fatigue limits of weathering steel under acid fog environment are remarkably decreased as compared with environment of distilled water. The corrosive constituents in acid fog has piled up the corrosion products on specimen surface and generated the corrosion pits. Because of the high stress concentration arising at this corrosion pit, relatively low fatigue limits were obtained for acid fog specimens.

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Optimal Design of I-type Girder in 2 Span Continuous Steel Bridges by LRFD (LRFD에 의한 2경간 연속 강교량 주부재의 최적화 설계)

  • 국중식;신영석
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.04a
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    • pp.78-85
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    • 1999
  • In this study, I-type girders used as main members of a two span continuous steel bridge, are optimally designed by a Load and Resistance Factor Design method(LRFD) using an numerical optimization method. The width, height web thickness and flange thickness of the main girder are set as design variables, and light weight design is attempted by choosing the cross-sectional area as an object function. The main program is coded with C++ and connected with optimization modul ADS, which is coded with FORTRAN. The results of the program show that the stress constraints of noncomposite section during the initial construction stage become active in the positive moment area and the service limit state constaints become active in the negative moment area.

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Development of XML-based Document Model and Its Applications for Integrated Management of Bridge Design Documents (교량설계문서의 통합관리를 위한 XML 기반의 문서모델 개발과 응용)

  • 이상호;김붕근;정동균;강형택
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.10a
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    • pp.179-184
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    • 2004
  • This paper presents a prototype of document schema to guarantee the consistency of the bridge design information during the life-cycle of bridge. The main component of document schema for bridge design information is derived from the Document Type Definition (DTD) Pool which is the Construction CALS/EC standard in Korea and the document schema is implemented by using the XML Schema. The ifcXML are adopted for representing product data of bridge. A pilot system adopting the document schema and its application to existing bridge show that the suggested document schema can be efficiently used to develop software modules supporting the integrated design documents for bridges.

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Properties of Prepacked Concrete Using Super Early Hardening Mortar (초속경성 모르타르를 주입한 프리팩트 콘크리트의 물성 평가)

  • Yang Seung Kyu;Jeong Yon Shik;Um Tai Sun;Lee Jong Ryul
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.651-654
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    • 2005
  • Fast-setting cement is usually used for emergency repair construction of roads, bridges, buildings and so on. In this study, we tried to develop fast-setting ultra early strength mortar for prepacked concrete and evaluated the properties of fresh and hardened concrete with it. The flowability of the mortar was high enough to be easily poured into coarse aggregates. It showed high early strength development which can make it possible to use newly constructed structures within $3\~4$ hours regardless of curing conditions such as curing temperature and curing environment. And it also showed good resistance to drying shrinkage and chemical attack.

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Feasibility Study on Road Bridge Passed by Heavy Equipment Transporter (HETS 차량의 교량 통과 가능성에 관한 연구)

  • Kang, Young-Chul;Lee, Pil-Jae
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.2
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    • pp.236-247
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    • 2009
  • In Korea, the driving system restriction criteria is strictly applied(gross weight 400kN, axial load 100kN). Especially after the Seoungsu Bridge accident, safety factor has been strictly applied. The Safety factor is applied to the cumulative results for each steps like design, construction, maintenance of the Bridge. Because of it, the bridge is undervalued compared to its capacity. So, this generates loss for both private and military sector(eg. logistical delays, structural damage, etc.). But analyzing data from many existing researches we have confirmed that the military heavy vehicle may pass through the first class bridges. In consequence, this study have focused on determining whether HETS vehicles can pass over the first class bridge, without safety issues, using MIDAS structural analysis program. The results have confirmed that the military heavy vehicle may pass over the bridge.

A Case Study on Continuous Prestressed Concrete Composite Girder with Cross-beam Anchorage System (가로보를 정착구조로 하는 연속화 PSC 합성거더 시공사례)

  • Park, Hyun-Myo;Huh, Young;Kim, Yun-Hwan;Kim, Seok-Tae
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.451-452
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    • 2010
  • Prestressed concrete I girder bridge has been one of the most widely used bridges in the world because of its excellent construction feasibility, economic efficiency, serviceability, and safety. But in Korea, the PSC bridge has not been utilized for long span because of high girder height in its standard design. Thus, the results confirm that it is possible to applicate the continuous PSC girder with end cross beam anchorage system using multi-stage prestressing technique.

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A Study on Field Measurement and Analysis of Train noise at Elevated Railway in Jeolla Line (전라선 고가교 연변 철도 소음 현장측정 및 분석에 관한 연구)

  • Kim, Byoung-Sam;Won, Chan-Hee;Kim, Dae-Jin
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.629-634
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    • 2001
  • The construction of the elevated railway has led to concerns about the noise from trains, particularly as tracks often pass close to residential dwellings. One specific issue relates to the noise from trains on bridges. The wayside noise for the train was measured to get the basic data that can be used to prepare count measures for solving environmental noise problems. Noise levels were measured simultaneously at three points in various distances from the railroad and at four points classified by floor. In this paper we measure the wayside noise in elevated railway and noise of normal operation compare with operating under train engine idling condition and investigate effect of nearby-building induced by train operation.

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Stress estimation of exposed gas pipeline using MEMS wireless tilt sensor (MEMS 무선 기울기 센서를 이용한 노출 배관 응력 추정)

  • Kim, Tack-Keun;Kang, In-Goo;Shin, Dong-Hoon;Chung, Tae-Yong;Nam, Jin-Hyun;Lim, Si-Hyung
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.404-408
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    • 2009
  • Gas pipelines in bridges, roads and subway construction sections can undergo abrupt stress and vibration changes. To protect human life from any gas leakage accidents induced by the abrupt stress and vibration, the gas pipeline system needs to be continuously monitored. The estimation method of pipeline stress using MEMS wireless tilt sensor has been developed and its validity has been evaluated using a lab test bench.

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Water bottom seismic refraction survey for engineering applications

  • Cha Young Ho;Jo Churl-Hyun
    • 한국지구물리탐사학회:학술대회논문집
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    • 2003.11a
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    • pp.449-454
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    • 2003
  • The accurate mapping of the basement is one of the most crucial factors in construction of harbour facilities and bridges in the coastal areas. In shallow waters, the seismic reflection method often fails to image the basement geometry beneath the sediment cover in many cases. We present the result of a shallow marine seismic refraction survey using two ships, l2-channel hydrophone arrays deployed on the bottom and a borehole sparker or percussion powder as sources. Velocity structure could be computed by tomography algorithm since more than 6 different source points had been applied for one spread. The comparison of the results of the refraction survey with drilling logs demonstrates remarkable consistency in basement geometry. It thus appears that the refraction method in this study is an efficient and cost-effective way to investigate the basement structure in coastal area, river, and lake.

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