• Title/Summary/Keyword: AASHOTO LRFD

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A Study on Safe Vessel Traffic Speeds Based On a Ship Collision Energy Analysis at Incheon Bridge (인천대교 선박 충돌에너지 분석을 통한 선박의 통항안전 속력에 관한 연구)

  • Lee, Chang-Hyun;Lee, Hong-Hoon;Kim, Deun-Bong;Kim, Chol-Seong;Park, Seong-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.22 no.6
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    • pp.593-599
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    • 2016
  • Incheon Bridge is 13.38 km long with an 800 m span, connecting Incheon International Airport and Songdo International City, Per hour 73.8 vessels navigate this space. The purpose of this study was to suggest a safe passing speed based on the displacement of a vessel based on the safety criteria of Incheon Bridge's anti-collision fence, which was designed during its initial construction. As AASHTO LRFD suggested, vessel collision energy, vessel collision velocity, and the hydrodynamic mass coefficient were considered to derive a safe vessel traffic speed. Incheon Bridge's anti-collision fence was designed so that 100,000 DWT vessels can navigate at a speed of 10 knot. This research suggests a safe speed for vessel traffic through a comparative analysis of an experimental ship's (300,000 DWT) speed and cargo conditions, regulation speed has been calculated according to the collision energy under each set of conditions. Additionally, safe traffic vessel's safe speed was analyzed with reference to tidal levels. Results from the experimental ship showed that a vessel of maximum 150,000 DWT is able to pass Incheon Bridge at a maximum of 7 knots with an above average water level, and is able to pass the bridge with a maximum of 8 knots under ballast conditions.

A Comparison Study of Direct Impact Analysis of Vehicle to Concrete Pier and In-Direct Impact Analysis using Load-Time History Functions (차량과 콘크리트 교각의 직접충돌해석법과 충돌하중이력곡선을 이용한 간접충돌해석법 비교연구)

  • Kim, WooSeok;Kim, Kyeongjin;Lee, Jaeha
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.6
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    • pp.533-542
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    • 2014
  • In design standards such as AASHTO LRFD and Korea Highway Bridge Design, the dynamic behaviors under the impact loading has not been considered and it recommends of using a static force for designing bridge column against vehicle collisions. Accordingly, in this study, models of vehicle collisions to concrete bridge column were developed with various boundary conditions in order to take into account dynamic behaviour of the column. Cargo trucks of 10tons, 16tons and 38tons were selected and a typical type of concrete bridge pier column along the Kyungbu highway in Korea was selected for this study. Results from this study indicate that the static load specified in the design standards are too small compared to results obtained in this study. It was also found that a consideration of the bridge superstructure allowed smaller damages of concrete bridge pier column under truck impact loadings. Furthermore, a comparison study of direct impact analysis of vehicle to bridge-column with in-direct impact analysis using load-time history functions was performed. The in-direct impact analysis shows that the use of load-time history graph improves the computational cost up to 92% and predict the behaviors of the bridge column under the impact loadings well. The obtained load-time history graph could be easily applied to several existing models.