Wind and Structures

  • 제12권5호
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  • Pages.413-424
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  • 2009
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  • 1226-6116(pISSN)
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  • 1598-6225(eISSN)
테크노프레스 (Techno-Press)
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DOI QR코드

DOI QR Code

Effects of frequency ratio on bridge aerodynamics determined by free-decay sectional model tests

  • Qin, X.R. (CLP Power Wind/Wave Tunnel Facility, HKUST) ;
  • Kwok, K.C.S. (CLP Power Wind/Wave Tunnel Facility, HKUST) ;
  • Fok, C.H. (CLP Power Wind/Wave Tunnel Facility, HKUST) ;
  • Hitchcock, P.A. (CLP Power Wind/Wave Tunnel Facility, HKUST)
  • 투고 : 2008.03.14
  • 심사 : 2009.05.12
  • 발행 : 2009.09.25
⟨ 이전 논문 다음 논문 ⟩

초록

A series of wind tunnel free-decay sectional model dynamic tests were conducted to examine the effects of torsional-to-vertical natural frequency ratio of 2DOF bridge dynamic systems on the aerodynamic and dynamic properties of bridge decks. The natural frequency ratios tested were around 2.2:1 and 1.2:1 respectively, with the fundamental vertical natural frequency of the system held constant for all the tests. Three 2.9 m long twin-deck bridge sectional models, with a zero, 16% (intermediate gap) and 35% (large gap) gap-to-width ratio, respectively, were tested to determine whether the effects of frequency ratio are dependent on bridge deck cross-section shapes. The results of wind tunnel tests suggest that for the model with a zero gap-width, a model to approximate a thin flat plate, the flutter derivatives, and consequently the aerodynamic forces, are relatively independent of the torsional-to-vertical frequency ratio for a relatively large range of reduced wind velocities, while for the models with an intermediate gap-width (around 16%) and a large gap-width (around 35%), some of the flutter derivatives, and therefore the aerodynamic forces, are evidently dependent on the frequency ratio for most of the tested reduced velocities. A comparison of the modal damping ratios also suggests that the torsional damping ratio is much more sensitive to the frequency ratio, especially for the two models with nonzero gap (16% and 35% gap-width). The test results clearly show that the effects of the frequency ratio on the flutter derivatives and the aerodynamic forces were dependent on the aerodynamic cross-section shape of the bridge deck.

키워드

참고문헌

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피인용 문헌

  1. An enhanced forced vibration rig for wind tunnel testing of bridge deck section models in arbitrary motion vol.164, 2017, https://doi.org/10.1016/j.jweia.2017.02.011
  2. Theoretical research on the identification method of bridge dynamic parameters using free decay response vol.38, pp.3, 2009, https://doi.org/10.12989/sem.2011.38.3.349
  3. Modeling of self-excited forces during multimode flutter: an experimental study vol.27, pp.5, 2009, https://doi.org/10.12989/was.2018.27.5.293