A predictive critical flutter wind speed modeling for long-span bridges

2020 ◽  
Vol 23 (9) ◽  
pp. 1823-1837
Author(s):  
Kun Lin ◽  
Minghai Wei ◽  
Hongjun Liu ◽  
Huafeng Wang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Wind Speeds ◽  
Long Span ◽  
Aerodynamic Model ◽  
Proposed Model

In this article, a two-dimensional Lighthill aerodynamic model is first extended to three-dimensional space, and then combined with the larger Von Karman plate deformation theory, a model for predicting the critical flutter wind speeds of long-span bridges in the primary design is proposed. The predictions of the presented model are compared to the results of wind tunnel tests for five long-span bridges with different main girder section forms. After that, based on the proposed model, the effects of width to span ratio and thickness to span ratio on the critical flutter wind speeds of long-span bridges are investigated. The results show that the differences between the proposed model and wind tunnel tests are only 7%–14%. Therefore, the presented model can assess the flutter wind speed in preliminary design stages of a bridge. The results also reveal that width to span ratios between 1/30 and 1/10 and thickness to span ratios between 1/300 and 1/100 are optimal for long-span bridges.

scholarly journals Wind-Induced Phenomena in Long-Span Cable-Supported Bridges: A Comparative Review of Wind Tunnel Tests and Computational Fluid Dynamics Modelling

2021 ◽  
Vol 11 (4) ◽  
pp. 1642
Author(s):  
Yuxiang Zhang ◽  
Philip Cardiff ◽  
Jennifer Keenahan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Careful Analysis ◽  
Wind Effects ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Long Span ◽  
Comparative Review ◽  
Dynamics Modelling

Engineers, architects, planners and designers must carefully consider the effects of wind in their work. Due to their slender and flexible nature, long-span bridges can often experience vibrations due to the wind, and so the careful analysis of wind effects is paramount. Traditionally, wind tunnel tests have been the preferred method of conducting bridge wind analysis. In recent times, owing to improved computational power, computational fluid dynamics simulations are coming to the fore as viable means of analysing wind effects on bridges. The focus of this paper is on long-span cable-supported bridges. Wind issues in long-span cable-supported bridges can include flutter, vortex-induced vibrations and rain–wind-induced vibrations. This paper presents a state-of-the-art review of research on the use of wind tunnel tests and computational fluid dynamics modelling of these wind issues on long-span bridges.

Flutter mitigation of a superlong-span suspension bridge with a double-deck truss girder through wind tunnel tests

2020 ◽  
pp. 107754632094615
Author(s):  
Yanguo Sun ◽  
Yongfu Lei ◽  
Ming Li ◽  
Haili Liao ◽  
Mingshui Li
Keyword(s):  
Wind Tunnel ◽  
Damping Ratio ◽  
Suspension Bridge ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Long Span ◽  
Upper Deck ◽  
Torsional Damping ◽  
And Control ◽  
Wind Induced Vibration

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.

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.

The Golden Proportion and Aesthetic Design of Long-Span Bridges

1998 ◽  
Vol 1624 (1) ◽  
pp. 36-46
Author(s):  
Ronald Yee
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Human Form ◽  
Aesthetic Design ◽  
Golden Proportion ◽  
Long Span Bridges ◽  
Creative Thought ◽  
Long Span ◽  
Basic Concepts ◽  
Three Dimensional Space

In recent years there has been a revival in the debate between architects and engineers about the aesthetics of bridges and who should be responsible for designing them. This subject is examined, and it is suggested that an understanding of the basic concepts, common sense, and cooperation among professionals are all necessary for pleasing designs. Good harmonious proportions in three-dimensional space are essential for achieving aesthetic beauty. This is particularly true in the design of long-span bridges. It is not sufficient for bridges to be just functional and mathematically correct, nor is it acceptable for the advantages of modern construction to be exploited for economic benefit without due consideration of aesthetics and the environment. Since earliest times, structures and buildings that have become universally accepted as good examples of aesthetic beauty have good proportions as the foundation of their design. Countless proportional theories have been proposed in the search of aesthetic beauty, each finding favor from time to time. However, only the Golden Proportion is based on the dimensions and ratios of the human form. By illustrating how proportion has been incorporated into the composition of some recent bridges, it is found that the appropriate use of proportion accompanied by creative thought and judgment can result in aesthetic structures.

scholarly journals A Quick Assessment and Optimization Method for a Flutter Aerodynamic Measure of a Typical Flat Box Girder

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Feng Wang ◽  
Chuan Xiong ◽  
Zijian Wang ◽  
Congmin Guo ◽  
Hua Bai ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Wind Tunnel ◽  
Energy Input ◽  
Test Procedure ◽  
Optimization Method ◽  
Box Girder ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Long Span ◽  
Quick Assessment

Flutter is one of the most serious wind-induced vibration phenomena for long-span bridges and may cause the collapse of a bridge (e.g., the Old Tacoma Bridge, 1940). The selection and optimization of flutter aerodynamic measures are difficult in wind tunnel tests. It usually takes a long time and consumes more experimental materials. This paper presents a quick assessment and design optimization method for the flutter stability of a typical flat box girder of the long-span bridges. Numerical analysis could provide a reference for wind tunnel tests and improve the efficiency of the test process. Based on the modal energy exchange in the flutter microvibration process, the global energy input and local energy input are analyzed to investigate the vibration suppression mechanism of a flat steel box girder with an upper central stabilizer. Based on the comparison between the experimental and numerical data, a quick assessment method for the optimization work is proposed. It is practical to predict the effects of flutter suppression measures by numerical analysis. Thus, a wind tunnel test procedure for flutter aerodynamic measures is proposed which could save time and experimental materials.

scholarly journals Design Wind Speed Estimation for Long Span Bridges in Korean Southern and Western Coasts

2020 ◽  
Vol 10 (2) ◽  
pp. 146-155
Author(s):  
Dooyong Cho
Keyword(s):  
Wind Speed ◽  
Least Squares ◽  
Return Period ◽  
Least Squares Method ◽  
Wind Load ◽  
Suspension Bridges ◽  
Method Of Moment ◽  
Long Span Bridges ◽  
Wind Speeds ◽  
Long Span

Recently, many long-span cable supported bridges, including the cable stayed bridges and the suspension bridges, have already been constructed or are planned for construction. Because the meteorological values used to estimate the wind load for designing the long-span bridges were based on data from the 1960s through 1995 in Korea, it is necessary to reconsider the proper design wind load for long-span bridges. In this paper, the research area is confined to the southern and western coasts of Korea where many long-span bridges have been built. The method of moment and the least-squares method are used to estimate the expected wind speeds of a 100-year return period for girder bridges; Gumbel’s distribution is used to estimate the expected wind speeds of a 200-year return period for long-span bridges. As the return period wind speed on the land surface is revised because of recent high-speed velocity, the revised return period wind speed is increased by 17%. The compatibility of return period wind speed is also evaluated using the RMS (root mean square) error method. This paper concludes that the least-squares method is more compatible than the method of moment for the case of the southern and western coasts of Korea.

scholarly journals Suppression of Bridge Flutter Using Suction Control

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shibo Tao
Keyword(s):  
Wind Speed ◽  
Leeward Side ◽  
Suction Velocity ◽  
Long Span Bridges ◽  
Wind Speeds ◽  
Long Span ◽  
Suction Control ◽  
Long Span Bridge ◽  
Section Model ◽  
Derivatives Of

To verify the effectiveness of the suction-based method for improving flutter stability of long-span bridges, the forced vibration experiments for extracting the flutter derivatives of a section model with and without suction were performed, and the corresponding critical flutter wind speeds of this structure were calculated out. It is shown by the experiment that the flutter stability of the bridge depends on suction configuration. As the suction holes locate at the leeward side of the model, the critical flutter wind speed can attain maximum under the same suction velocity. In the analytical results, it is remarkably effective that the suction control improves the long-span bridge flutter stability.

Method for Designing Three-Dimensional Swept Hybrid Wings for Icing Wind-Tunnel Tests

2019 ◽  
Vol 56 (2) ◽  
pp. 730-746 ◽  
Author(s):  
Gustavo E. C. Fujiwara ◽  
Michael B. Bragg
Keyword(s):  
Wind Tunnel ◽  
Three Dimensional ◽  
Wind Tunnel Tests
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