Wind tunnel experiment of long-span suspension bridge using 3D models

1991 ◽  
Vol 1991 (46) ◽  
pp. 1-17 ◽  
Author(s):  
Yozo FUJINO ◽  
Masami IWAMOTO ◽  
Manabu ITO ◽  
Yuichi HIKAMI ◽  
Katsuaki TAKEDA ◽  
...  
2014 ◽  
Vol 633-634 ◽  
pp. 1263-1266
Author(s):  
Huang Yu

For modern long-span bridges, both the optimization of aerodynamic shape and the increase of torsional stiffness according to the result of the wind tunnel experiment could avoid the flutter instability.Vortex-inducedvibration with relatively large amplitude happens easily at low wind speeds. In this paper, based on wind tunnel experiment, by studying on the vortex-induced vibration characteristics of a long-span suspension bridge with single cable plane, aerodynamic measures for easing the vortex-induced vibration are given.


2020 ◽  
pp. 107754632094615
Author(s):  
Yanguo Sun ◽  
Yongfu Lei ◽  
Ming Li ◽  
Haili Liao ◽  
Mingshui Li

As flutter is a very dangerous wind-induced vibration phenomenon, the mitigation and control of flutter are crucial for the design of long-span bridges. In the present study, via a large number of section model wind tunnel tests, the flutter performance of a superlong-span suspension bridge with a double-deck truss girder was studied, and a series of aerodynamic and structural measures were used to mitigate and control its flutter instability. The results show that soft flutter characterized by a lack of an evident divergent point occurred for the double-deck truss girder. Upper central stabilizers on the upper deck, lower stabilizers below the lower deck, and horizontal flaps installed beside the bottoms of the sidewalks are all effective in suppressing flutter for this kind of truss girder. By combining the structural design with aerodynamic optimizations, a redesigned truss girder with widened upper carriers and sidewalks, and double lower stabilizers combined with the inspection vehicle rails is identified as the optimal flutter mitigation scheme. It was also found that the critical flutter wind speed increases with the torsional damping ratio, indicating that the dampers may be efficient in controlling soft flutter characterized by single-degree-of-freedom torsional vibration. This study aims to provide a useful reference and guidance for the flutter design optimization of long-span bridges with double-deck truss girders.


2013 ◽  
Vol 791-793 ◽  
pp. 378-381
Author(s):  
Hua Bai ◽  
Sen Hua Huang

The flutter stability of the steel truss suspension bridge is hard to reach the requirement of the wind resisting stability when lacks the torsional stiffness. This paper discusses the influence of aerodynamic measure combination, such as central stabilizer, air director enclosed anti-collision bar and so on, towards the flutter stability of steel truss through the wind tunnel experiment of the bridge of Liu Jia gorge. The result shows: the effect of using both the upper and lower stabilized plate is better than separated used it. when sectionalized dispose upper stabilized plate, the flutter critical wind speed of attack angle will decrease rapidly. Outlaying the horizontal guide plate is better than internally installed; The flutter stability of different attack angle tend to be balanced by widening the horizontal guide plate. The anti-collision bar can be functionalized as the central stabilizer by heightening and enclosing, and effectively increase the critical wind speed of different attack angles of the high truss suspension bridge.


2011 ◽  
Vol 66-68 ◽  
pp. 334-339
Author(s):  
Mei Yu ◽  
Hai Li Liao ◽  
Ming Shui Li ◽  
Cun Ming Ma ◽  
Nan Luo ◽  
...  

Long-span suspension bridges, due to their flexibility and lightness, are much prone to the wind loads, aerodynamics performance has become an important aspect of the design of long-span suspension bridges. In this study, the static wind load acting on the suspension bridge during erection has been investigated through wind tunnel test and numerical analysis. The wind tunnel test was performed using a 1:50 scale section model of the bridge, the static wind load acting on the section model was measured with varying attack angles. Numerical method used here was computational fluid dynamics simulation, a two-dimensional model is adopted in the first stage of the analysis, then the SIMPLE algorithm was employed to solve the governing equations. The analytical results were compared with the wind tunnel test data, it was shown from the study that the results of CFD simulation was good agreement with that of the wind tunnel test.


Author(s):  
Ming Li ◽  
Yanguo Sun ◽  
Yongfu Lei ◽  
Haili Liao ◽  
Mingshui Li

The purpose of this study is to investigate the nonlinear torsional flutter of a long-span suspension bridge with a double-deck truss girder. First, the characteristics of nonlinear flutter are studied using the section model in the wind tunnel test. Different aerodynamic measures, e.g. upper and lower stabilizers and horizontal flaps, are applied to improve the flutter performance of the double-deck truss girder. Then, the full bridge aeroelastic model is tested in the wind tunnel to further examine the flutter performance of the bridge with the optimal truss girder. Finally, three-dimensional (3D) flutter analysis is performed to study the static wind-induced effects on the nonlinear flutter of the long-span suspension bridge. The results show that single-degree-of-freedom torsional limit cycle oscillations occur at large amplitudes for the double-deck truss section at the attack angles of [Formula: see text] and [Formula: see text]. The upper and lower stabilizers installed on the upper and lower decks, respectively, and the flaps installed near the bottoms of the sidewalks can all effectively alleviate the torsional flutter responses. Meanwhile, it is found that the torsional flutter responses of the truss girder in the aeroelastic model test are much smaller than those in the section model test. The 3D flutter analysis demonstrates that the large discrepancies between the flutter responses of the two model experiments can be attributed to the additional attack angle caused by the static wind-induced displacements. This finding highlights the importance and necessity of considering the static wind-induced effects in the flutter design of long-span suspension bridges.


2020 ◽  
Vol 2020 ◽  
pp. 1-22
Author(s):  
Bo Wu ◽  
Liang-Liang Zhang ◽  
Yang Yang ◽  
Lian-Jie Liu ◽  
Zhi-Jun Ni

The field measurements, wind tunnel tests, and numerical calculations are utilized to conduct refined time-domain buffeting analysis of a long-span suspension bridge. The wind characteristics in the mountainous urban terrain are obtained through long-term field measurements. The aerostatic force coefficients (AFCs) and aerodynamic admittance functions (AAFs) are experimentally tested in a wind tunnel. The fluctuating wind fields on the bridge are simulated by the spectral representation method. Finally, the buffeting responses are calculated in ANSYS. The influences of AAF, turbulence power spectrum, and angle of attack (AoA) on the buffeting responses are evaluated, which highlight the inaccuracies caused by empirical simplifications. To improve the buffeting performance without a considerable extra budget, minor modifications are introduced to the original design configuration. The buffeting responses are slightly reduced by increasing the ventilation rate of guardrails, and the control efficiency is better when concurrently moving the inspection rails inward. Besides, the buffeting responses are increased when considering the roughness on the girder surface. The influence mechanism of the countermeasure is analyzed using the Computational Fluid Dynamics (CFD) method, which mainly lies in the dissipation of turbulence energy around the girder. The findings can contribute to the wind-resistant analysis and optimization design for similar bridges.


1990 ◽  
Vol 33 (1-2) ◽  
pp. 313-322 ◽  
Author(s):  
Yozo Fujino ◽  
Manabu Ito ◽  
Izumi Shino ◽  
Masami Iwamoto ◽  
Yu-Ichi Hikami ◽  
...  

2006 ◽  
Vol 11 (3) ◽  
pp. 293-318 ◽  
Author(s):  
M. Zribi ◽  
N. B. Almutairi ◽  
M. Abdel-Rohman

The flexibility and low damping of the long span suspended cables in suspension bridges makes them prone to vibrations due to wind and moving loads which affect the dynamic responses of the suspended cables and the bridge deck. This paper investigates the control of vibrations of a suspension bridge due to a vertical load moving on the bridge deck with a constant speed. A vertical cable between the bridge deck and the suspended cables is used to install a hydraulic actuator able to generate an active control force on the bridge deck. Two control schemes are proposed to generate the control force needed to reduce the vertical vibrations in the suspended cables and in the bridge deck. The proposed controllers, whose design is based on Lyapunov theory, guarantee the asymptotic stability of the system. The MATLAB software is used to simulate the performance of the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a velocity feedback controller.


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