Experimental Investigation into Aerodynamic Stability of Narrow Steel Truss Girder Suspension Bridge

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.

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.


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.


Author(s):  
Dusan Radojevic ◽  
Keith Kirkwood

The Angus L. Macdonald Bridge, a major suspension bridge that crosses Halifax Harbour in Halifax, Nova Scotia, opened to traffic in 1955. The bridge deck has reached the end of its service life, and the design of the new bridge superstructure and its replacement sequence were completed in 2014. The entire suspended structure and hangers are now being replaced sequentially during night and weekend closures while the bridge is opened for traffic during the daytime. The erection sequence is supported by sophisticated automated erection analysis models which take into account the geometry of the existing bridge, positioning of the erection equipment on the deck, and hanger and strand jack adjustments that are required during construction. Significant wind tunnel testing and analysis have been performed to ensure aerodynamic stability of the bridge during erection and in its final condition.


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.


2021 ◽  
Vol 1201 (1) ◽  
pp. 012007
Author(s):  
I. Kusano ◽  
E. Cheynet ◽  
J. B. Jakobsen ◽  
J. Snæbjörnsson

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.


2011 ◽  
Vol 301-303 ◽  
pp. 780-784
Author(s):  
Liang Gao ◽  
Jian Xin Liu ◽  
Miao Liu

With HK-Zhuhai-Macau Bridge as the engineering background, through the section model wind tunnel test, research into the influence of vibration damping measure to the static aerodynamic coefficients of the structure, so as to seek to improve structural characteristics. The influencing factors of static aerodynamic coefficients including the guide plate position, the central trough opening rate, baluster drafty rate, repair car track position, windbreak, and vehicle. The results show that the changes of the static aerodynamic coefficients directly affect the static wind loads, and the influence of changes of these parameters to the static wind load cannot be ignored.


Sign in / Sign up

Export Citation Format

Share Document