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Simplified formulations for flutter instability analysis of bridge deck

  • Vu, Tan-Van;Kim, Young-Min;Han, Tong-Seok;Lee, Hak-Eun
    • Wind and Structures
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    • v.14 no.4
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    • pp.359-381
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    • 2011
  • This paper deals with the flutter instability problem of flexible bridge decks in the framework of bimodal-coupled aeroelastic bridge system analysis. Based on the analysis of coefficients of the polynomials deduced from the singularity conditions of an integral wind-structure impedance matrix, a set of simplified formulations for calculating the critical wind velocity and coupled frequency are presented. Several case studies are discussed and comparisons with available approximated approaches are made and presented, along with a conventional complex eigenvalue analysis and numerical results. From the results, it is found that the formulas that are presented in this study are applicable to a variety of bridge cross sections that are not only prone to coupled-mode but also to single-mode-dominated flutter.

Wind-induced response and loads for the Confederation Bridge -Part II: derivation of wind loads

  • Bakht, Bilal;King, J. Peter C.;Bartlett, F.M.
    • Wind and Structures
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    • v.16 no.4
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    • pp.393-409
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    • 2013
  • This paper uses ten years of on-site monitoring data for the Confederation Bridge to derive wind loads and investigate whether the bridge has experienced its design wind force effects since its completion in 1997. The load effects derived using loads from the on-site monitoring data are compared to the load effects derived using loads from the 1994 and 2009 wind tunnel aerodynamic model tests. The research shows, for the first time, that the aerodynamic model-based methodology originally developed in 1994 is a very accurate method for deriving wind loads for structural design. The research also confirms that the bridge has not experienced its specified (i.e., unfactored) wind force effects since it was opened to traffic in 1997, even during the most severe event that has occurred during this period.

Seismic evaluation of isolated skewed bridges using fragility function methodology

  • Bayat, M.;Daneshjoo, F.;Nistico, N.;Pejovic, J.
    • Computers and Concrete
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    • v.20 no.4
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    • pp.419-427
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    • 2017
  • A methodology, based on fragility functions, is proposed to evaluate the seismic performance of seismic isolated $45^{\circ}$ skewed concrete bridge: 1) twelve types of seismic isolation devices are considered based on two different design parameters 2) fragility functions of a three-span bridge with and without seismic isolation devices are analytically evaluated based on 3D nonlinear incremental dynamic analyses which seismic input consists of 20 selected ground motions. The optimum combinations of isolation device design parameters are identified comparing, for different limit states, the performance of 1) the Seismic Isolated Bridges (SIB) and 2) Not Seismic Isolated Bridge (NSIB) designed according to the AASHTO standards.

A Study on Performance Improvements about Duct of Smoke Control System Combined with Air-Conditioning Equipment (공기조화설비 겸용 제연설비 덕트의 성능개선을 위한 연구)

  • Oh, Teakhum;Park, Chanseok
    • Journal of the Korea Safety Management & Science
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    • v.23 no.4
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    • pp.67-72
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    • 2021
  • To ensure the safety and functionality of a railroad bridge, maintaining the integrity of the bridge via continuous structural health monitoring is important. However, most structural integrity monitoring methods proposed to date are based on modal responses which require the extracting process and have limited availability. In this paper, the applicability of the existing damage identification method based on free-vibration reponses to time-domain deflection shapes due to moving train load is investigated. Since the proposed method directly utilizes the time-domain responses of the structure due to the moving vehicles, the extracting process for modal responses can be avoided, and the applicability of structural health evaluation can be enhanced. The feasibility of the presented method is verified via a numerical example of a simple plate girder bridge.

Drilled Shaft Designs and Constructions using Pile Load Tests at the Government-Financed Section of Incheon Bridge (재하시험을 활용한 인천대교 국고구간 현장타설말뚝의 설계와 시공)

  • Cho, Sung-Min;Jeon, Byeong-Seob;Chung, Il-Hwan;Choi, Go-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.10a
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    • pp.562-573
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    • 2006
  • Incheon Bridge which will be the world's 5th long cable-stayed bridge in 2009 has been built under the management by Korea Highway Corporation. Incheon Bridge consists of several special-featured bridges and construction sections are divided into two groups, the private investment section with the foreign concessionaire and the government-financed section. 8 pile load tests were performed to investigate the behavior of rock-embedded large-diameter drilled shafts at both sections. Among these, 4 tests at the government-financed section have been utilized to adjust the detailed designs that were carried out individually as well as to find the actual bearing capacity of the ground prior to the commencement of constructions under the joint control of all contractors. Comprehensive procedures of the design and the construction of foundations using pile load tests were introduced.

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