Aerodynamic Stability of a Three-Tower Suspension Bridge during Erection via Aeroelastic Model Test

2013 ◽  
Vol 405-408 ◽  
pp. 1494-1499
Author(s):  
Wen Ming Zhang ◽  
Yao Jun Ge
Keyword(s):  
Wind Speed ◽  
Cross Section ◽  
Model Test ◽  
Frequency Ratio ◽  
Suspension Bridge ◽  
Aerodynamic Stability ◽  
Wind Speeds ◽  
Critical Wind Speed ◽  
Long Span ◽  
Aeroelastic Model

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.

The Influence of Turbulence Integral Scale to Buffeting of Long-Span Bridge

2011 ◽  
Vol 105-107 ◽  
pp. 9-12 ◽  
Author(s):  
Yi Qing Xiao ◽  
Gang Hu ◽  
Meng Qi Tu ◽  
Rui Qi Zheng
Keyword(s):  
Wind Speed ◽  
Suspension Bridge ◽  
Numerical Results ◽  
Integral Scale ◽  
Wind Speeds ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Integral Scales ◽  
Long Span Bridge ◽  
Peak Value

In this paper, the influence of turbulence integral scale to buffeting responses of long-span bridge is analyzed by adopting 2-D buffeting theory. One cable-stayed bridge and one suspension bridge are selected as analysis object. Buffeting responses are calculated under two different wind speeds and different size of turbulence integral scales, which range from 10m to 80m in this paper. The numerical results show that buffeting responses do not change with turbulence integral scale linearly and when turbulence integral scale increases to one value, buffeting responses reach a peak. In addition, turbulence integral scale corresponding to peak value of buffeting responses rise with growth of wind speed.

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

2021 ◽  
pp. 2150102
Author(s):  
Ming Li ◽  
Yanguo Sun ◽  
Yongfu Lei ◽  
Haili Liao ◽  
Mingshui Li
Keyword(s):  
Wind Tunnel ◽  
Model Test ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Nonlinear Flutter ◽  
Long Span ◽  
Aeroelastic Model ◽  
Flutter Analysis ◽  
Section Model

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.

scholarly journals Analysis of the rainfall influence on critical wind speed of flutter of long-span suspension bridge based on mumerical method

2020 ◽  
Vol 319 ◽  
pp. 07002
Author(s):  
Hu Jun
Keyword(s):  
Wind Speed ◽  
Suspension Bridge ◽  
Movement Speed ◽  
Suspension Bridges ◽  
Mountainous Area ◽  
Element Analysis ◽  
Critical Wind Speed ◽  
Damping Matrix ◽  
Long Span ◽  
The Impact

In order to study the influence of rainfall on the critical wind speed of flutter of long-span suspension bridges in mountainous area, the impact of rainfall on stiffening girder is analyzed based on the main characteristics of rainfall and the movement speed in all directions. The mechanical equation under the joint action of wind and rain is established and the impact force is transferred, the damping effect of rainfall is then derived, and the element damping matrix form of rainfall is obtained by combining the integration of shape function. Furthermore, the flutter motion equation of wind-rain-bridge coupling system is derived, and the finite element analysis method for critical wind speed of structural flutter considering the influence of rainfall is established. Finally, taking a large-span suspension bridge in mountainous area as the research object, the influence of rainfall on the critical wind speed of flutter is analyzed, the results indicate that the critical wind speed of flutter will be accordingly increased due to the existence of rainfall damping, whereas the mass of raindrops is too light and the final velocity of raindrops in the falling process is low, the critical wind speed of flutter increased by only 5.54% in the case of heavy rainstorm. Therefore, when the rainfall intensity is general, the influence of rainfall on the critical wind speed of flutter can be ignored.

scholarly journals Effects of central stabilizing barriers on flutter performances of a suspension bridge with a truss-stiffened deck under skew winds

2018 ◽  
Vol 22 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Ledong Zhu ◽  
Xiao Tan ◽  
Zhenshan Guo ◽  
Quanshun Ding
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Inclination Angle ◽  
Suspension Bridge ◽  
Control Measures ◽  
Wind Effect ◽  
Wind Condition ◽  
Wind Tunnel Tests ◽  
Critical Wind Speed ◽  
Bridge Span

To improve the flutter performance of a suspension bridge with a 1088-m-span truss-stiffened deck, the aerodynamic measures of upper and lower central stabilizing barriers were investigated at first via wind tunnel tests of sectional model under the normal wind condition. The yaw wind effect on the flutter performance of the bridge with the above aerodynamic measures was then examined via a series of wind tunnel tests of oblique sectional models. The test results show that the effect of the lower central stabilizing barrier on the flutter critical wind speed is remarkably different from that of the upper central stabilizing barrier for both the normal and skew wind cases. The inclination angle +3° is the most unfavorable inclination angle to the flutter performance of the truss-stiffened suspension bridge no matter whether the aerodynamic control measures are adopted or not. Furthermore, for most cases, the lowest flutter critical wind speed occurs when the incident wind deviates from the normal direction of the bridge span by a small yaw angle between 5° and 10°.

Research on the Aerodynamic Measures Impact on Flutter Stability of Steel Truss Suspension Bridge

2013 ◽  
Vol 791-793 ◽  
pp. 378-381
Author(s):  
Hua Bai ◽  
Sen Hua Huang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Suspension Bridge ◽  
Wind Tunnel Experiment ◽  
Attack Angle ◽  
Torsional Stiffness ◽  
Critical Wind Speed ◽  
Guide Plate ◽  
Steel Truss ◽  
Better Than

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.

Feasibility Study of Super-Long Span Bridges Considering Aerostatic Instability by a Two-Stage Geometric Nonlinear Analysis

2020 ◽  
pp. 2150033
Author(s):  
Jiunn-Yin Tsay
Keyword(s):  
Wind Speed ◽  
Nonlinear Analysis ◽  
Two Stage ◽  
Long Span Bridges ◽  
Critical Wind Speed ◽  
Long Span ◽  
Main Cable ◽  
Geometric Nonlinear ◽  
Long Span Bridge ◽  
Geometric Nonlinear Analysis

To meet the need of constructing fixed cross strait links, super-long span bridge with a main span over 2 000[Formula: see text]m is considered as a candidate for their ability to cross deep and wide straits. To this end, some super-long span bridges with proper cable and girder systems were previously proposed and studied. The major design considerations are aimed at adopting new cable material, increasing the entire rigidity of the bridge, stabilizing the dynamic characteristics, strengthening the deck sections, etc. In this paper, a brief review of main cable and girder system is first given of the concepts previously proposed for the design of super-long span bridges. Then some typical examples are studied, focused on various issues related to the design of super-long span bridges, including composite cable, the unstressed length and tension force of the main cable, the stiffness and mass effects of the deck on critical wind speed, and the critical wind speed of various cable systems. The most challenges in super-long span bridges are to solve aerostatic and aerodynamic instability at required design wind speed. In this connection, the wind-induced aerostatic instability of super-long span bridges is studied by a two-stage geometric nonlinear analysis for dead loads and wind loads. The developed program adopted herein for geometric nonlinear analysis was verified and confirmed before. The proposed methods (i.e. composite cable, slotted girder, increasing deck stiffness and mass, cable layout, etc.) obtained for all the examples are in agreement with this study, which indicates applicability of the design approaches presented.

Comparison of wind characteristics at different heights of deep-cut canyon based on field measurement

2019 ◽  
Vol 23 (2) ◽  
pp. 219-233 ◽  
Author(s):  
Jingyu Zhang ◽  
Mingjin Zhang ◽  
Yongle Li ◽  
Chen Fang
Keyword(s):  
Wind Speed ◽  
Vertical Direction ◽  
Suspension Bridge ◽  
Longitudinal Direction ◽  
Longitudinal Component ◽  
Attack Angle ◽  
Gust Factor ◽  
Long Span ◽  
Wind Characteristic ◽  
Wind Characteristics

The typical U-shaped deep-cut canyon is widely distributed in the western mountainous areas of China, especially in Sichuan province and Yunnan province. The deep-cut canyon has the characteristics of the high drop in elevation, high-temperature difference, and complex wind environment. A 50 m high meteorological mast with a total of eight anemometers was erected in such topography, and a long-span suspension bridge will be constructed in the area where the meteorological mast is located. Based on the long-term monitor data, the wind characteristic parameters including average and fluctuating wind characteristics and coherence between different heights are investigated. The results are as follows. The dominant wind direction which depends on the topography is north–south. The attack angle of wind is mainly less than zero, and its probability distribution obeys the hypothetical Gaussian distribution. Both the increases in height of anemometer and in wind speed reduce the dispersion of the attack angle of wind. The gust factor has a similar change law of attack angle of wind. Turbulence intensities are affected by the height of the anemometer and the wind speed, and they are different from the recommended value of China Codes. In terms of turbulence integral length scale, the value increases with an increase in the height of the anemometer in the same component. The largest value occurs in the longitudinal direction and the smallest occurs in the vertical direction at the same level. The coherence between any two locations is relatively strong, and the longitudinal component is stronger than others. The measured wind power spectrum for longitudinal, lateral, and vertical wind in deep-cut canyon fits the von Kármán model better.

Wind Tunnel Studyon Vortex-Induced Vibration Characteristics of Long-Span Suspension Bridges with Single Cable Plane

2014 ◽  
Vol 633-634 ◽  
pp. 1263-1266
Author(s):  
Huang Yu
Keyword(s):  
Wind Tunnel ◽  
Suspension Bridge ◽  
Wind Tunnel Experiment ◽  
Vibration Characteristics ◽  
Torsional Stiffness ◽  
Suspension Bridges ◽  
Vortex Induced Vibration ◽  
Long Span Bridges ◽  
Wind Speeds ◽  
Long Span

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.

Aerodynamic Stability of Long-Span Suspension Bridge with Slotted Girder

2001 ◽  
Vol 84 (8) ◽  
pp. 9-16
Author(s):  
Shigeru Hirano ◽  
Shinichiro Ito ◽  
Hiroshi Sato ◽  
Shigeki Kusuhara
Keyword(s):  
Suspension Bridge ◽  
Aerodynamic Stability ◽  
Long Span

Research on the Impact of Damping to the Flutter Derivatives of Steel Truss Suspension Bridge

2012 ◽  
Vol 532-533 ◽  
pp. 325-329
Author(s):  
Hua Bai ◽  
Cheng Fang ◽  
Yu Li
Keyword(s):  
Wind Speed ◽  
Damping Ratio ◽  
Angle Of Attack ◽  
Suspension Bridge ◽  
Gansu Province ◽  
Critical Wind Speed ◽  
Flutter Derivative ◽  
Torsional Damping ◽  
The Impact ◽  
Flutter Derivatives

The flutter derivative is the important basic tache of bridge flutter stability analysis. Taking the Liujiaxia Bridge in Gansu province as the research object, this dissertation studies the impaction of damping ratio on the flutter derivatives and the critical wind speed through different series of section model vibration test. The results showed that the change of vertical bending and torsional damping ratio have no obvious regular influence on the eight flutter derivatives. But the changing of vertical bending and torsional damping ratio have the greatly impact on the critical wind speed at 0° and -3° angle of attack. When it is at 0° angle of attack ,the vertical bending damping ratio ζh is increased by 23%,the torsional damping ratio is increased by 0.63%, the flutter critical wind speed is increased by 4%;when the ζh is increased by 1.04%, the ζα is increased by 0.87% , the flutter critical wind speed is increased by 7%. When it is at -3° angle of attack, the vertical bending damping ratio remained around 0.8%, the torsional damping ratio is increased from 0.65% to 1.05%, the flutter critical wind speed is increased by 14%; when the ζα is increased from 0.65% to 2.05%, the flutter critical wind speed is increased by 24 %.When it is at +3 °angle of attack, the vertical bending and torsion damping ratio have little effect on the flutter critical wind speed.

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