Experimental Study of the Nonlinear Torsional Flutter of a Long-Span Suspension Bridge with a Double-Deck Truss Girder

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.

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.


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.


2011 ◽  
Vol 255-260 ◽  
pp. 938-941
Author(s):  
Hua Bai ◽  
Jia Wu Li

A narrow steel truss girder suspension bridge was designed for pedestrian and livestock in pasture in Xinjiang Province, China. For the complex wind climate at bridge site, the cautious designers resorted to wind tunnel test to confirm the aerodynamic stability of the bridge. The analysis and results from wind tunnel test conducted in Chang’an Wind Tunnel Laboratory indicated the original scheme must be changed considerably to improve the aerodynamic stability under action of wind. Considering the shape feature of Siudirgol Bridge and its geographical location, section model with such mitigation measures as auxiliary cables and central buckles were re-tested in wind tunnel joint with analysis. The auxiliary cables and central buckles can increase considerably the fundamental frequency of the bridge and hence the critical wind speed of flutter.


2019 ◽  
Vol 10 (1) ◽  
pp. 04018025 ◽  
Author(s):  
G. H. Li ◽  
W. J. Wang ◽  
X. C. Ma ◽  
L. B. Zuo ◽  
F. B. Wang ◽  
...  

Author(s):  
Xin-Jun Zhang ◽  
Fu-Bin Ying ◽  
Lei-Lei Sun

Based on the aerostatic and self-excited aerodynamic force models, a computational approach of three-dimensional (3D) refined flutter analysis for long-span bridges under skew winds is established, in which the structural nonlinearity, aerostatic effect and full-mode coupling effect, etc., are fully considered, and the computational procedure ([Formula: see text] flutter-sw) is developed accordingly. By taking the Runyang Suspension Bridge over the Yangtze river as an example, under the wind attack with initial angles of 0∘ and [Formula: see text] and yaw angles between 0∘ and 25∘, the flutter stability of the bridge in completion under skew winds is analyzed, and the influences of skew wind and aerostatic effect on the flutter stability of suspension bridges are assessed. The results show that the aerostatic effect has a significant influence on the flutter stability of long-span suspension bridge, and it may worsen its flutter stability, with an average decrease of 6.0%. However, it does not change the evolution of flutter stability of suspension bridge with increasing wind yaw angle. The critical flutter wind speed fluctuates with the increase of wind yaw angle, and it reaches the lowest value mostly under the skew wind, with an average reduction of 8.0%. The combined influence of the aerostatic effect and skew wind further reduces the flutter critical wind speed by 11.5% on average, and therefore, the aerostatic effect, skew wind effect and their adverse influences need to be comprehensively considered in the flutter analysis of long-span suspension bridges.


2011 ◽  
Vol 243-249 ◽  
pp. 1629-1633
Author(s):  
Mei Yu ◽  
Hai Li Liao ◽  
Ming Shui Li ◽  
Cun Ming Ma ◽  
Ming Liu

Aerodynamic stability is an issue in the wind-resistant design of long-span bridges, flutter is an aerodynamic instability phenomenon that occurs due to interactions between wind and structural motion. The Xihoumen Bridge is the second long suspension bridge in the world, the aeroelastic performance of the Xihoumen Bridge is investigated by wind tunnel testing and an analytical approach. In the case, wind-tunnel testing was performed using an aeroelastic full model of the bridge, and two section models of the bridge. Flutter derivatives of bridge decks are routinely extracted from wind tunnel section model experiments for the assessment of performance against wind loading, the analytical method used here were a two-dimensional flutter analysis and a multi-mode analysis in the frequency domain. The analytical results were compared with the wind tunnel test data; it showed that the flutter analysis results were good agreement with the wind-tunnel test data.


2013 ◽  
Vol 405-408 ◽  
pp. 1494-1499
Author(s):  
Wen Ming Zhang ◽  
Yao Jun Ge

As a new long-span suspension bridge with double main spans and a typical closed streamline cross-section of single box deck, the flutter performance of the Maanshan Bridge during erection was investigated via a full bridge aeroelastic model test. Critical flutter wind speeds of 13 testing cases with different percentage of deck completion are much higher than the flutter checking wind speeds, and the bridge is hence proven to be stable enough during erection in aerodynamics. The case with the percentage of deck completion of 86.4% gets the lowest flutter critical wind speed, perhaps because frequency ratio gets the minimum value at this case.


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.


2013 ◽  
Vol 361-363 ◽  
pp. 1105-1109
Author(s):  
Chun Sheng Shu

Liujiaxia Bridge is a truss stiffening girder suspension bridge which span is 536m, and it is the narrowest suspension bridge with the same scale, so the problems of flutter stability are prominent. Results of wind tunnel test show that its critical velocity cannot meet the requirements without any aerodynamic measures. Based on above considerations, seven kinds of aerodynamic measures are proposed, respectively wind tunnel tests are conducted. The results show that the program, in which the upper central stable board is 1.12m high and the under central stable board is 1.28m high, can meet the requirements. The results of this study provide some references to solving the problem of wind-resistant stability of narrow deck suspension bridge.


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