Monitoring-based evaluation of dynamic characteristics of a long span suspension bridge under typhoons

2021 ◽  
Vol 11 (2) ◽  
pp. 397-410
Author(s):  
Jian Guo ◽  
Cheng-Jie Hu ◽  
Min-Jun Zhu ◽  
Yi-Qing Ni
Keyword(s):  
Dynamic Characteristics ◽  
Suspension Bridge ◽  
Long Span

The Influence of the Cable Parameters on Vibration Characteristics of a Long-Span Suspension Bridge

2013 ◽  
Vol 694-697 ◽  
pp. 476-480
Author(s):  
Hai Qing Zhu ◽  
Xie Dong Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Optimization Design ◽  
Suspension Bridge ◽  
Element Model ◽  
Suspension Bridges ◽  
Cable System ◽  
Long Span ◽  
Long Span Bridge ◽  
The World ◽  
Set Up

The type of suspension bridge is used all over the world because of its long span. But the cable system which forced the main load is vulnerable to damage and corrosion. In order to discuss the dynamic characteristics of typical long-span suspension bridges, a finite-element model of a typical long-span bridge was set up with ANSYS, and its top ten frequencies and vibration types were calculated. What’s more the dynamic characteristics under the variations such as modulus of elasticity, sectional size of the cable system, initial strain of the cable, as well as the deficiency of suspender cable were discussed. According to the analysis, the researchers got the conclusion that how the cable system impacts the whole bridge and which suspender cable plays the most significant role. Moreover, the results could serve as some valuable references for the optimization design and preservation of long-span suspension bridges.

scholarly journals Parametric analysis of the dynamic characteristics of a long-span three-tower self-anchored suspension bridge with a composite girder

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Feifei Shao ◽  
Zhijun Chen ◽  
Hanbin Ge
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Suspension Bridge ◽  
Bending Stiffness ◽  
Torsional Stiffness ◽  
Design Parameters ◽  
Long Span ◽  
Bending Mode ◽  
Main Cables ◽  
Central Buckle

Abstract Three-tower self-anchored suspension bridge (TSSB) is more and more favored because of its beautiful structure and strong adaptability to terrain and geological conditions. However, there are few engineering practices and related researches on super long-span three-tower self-anchored suspension bridges. A three-dimensional finite element model for the Fenghuang Yellow River Bridge, with the world’s longest span of its kind under construction, is established using the ANSYS finite element program, and the structural dynamic characteristics of the super long-span TSSB are studied and compared with those of several bridges of the same type or with similar spans. In addition, the influence of the key design parameters such as the stiffening girder stiffness, tower stiffness, main cable and suspender stiffness, central buckle, and longitudinal constraint system on the dynamic characteristics of the structure is analyzed. The results show that the first mode of the TSSB is longitudinal floating, the lower-order modes are dominated by vertical bending modes, while the higher-order modes are primarily vibration modes of the main cables, and the torsional modes exhibit strong coupling with the lateral sway of the towers and main cables. The frequency of the first antisymmetric vertical bending mode of the TSSB has an inversely proportional relationship with the main span length. Compared with a double-tower ground-anchored suspension bridge and cable-stayed bridge with similar spans, the TSSB has the lowest frequency for the first antisymmetric vertical bending mode and the highest frequency for the first symmetric vertical bending mode, with a more pronounced coupling with the towers and main cables in the torsional modes. Analysis of the structural parameters shows that the frequencies of the longitudinal floating mode, first antisymmetric vertical bending mode, first symmetric vertical bending mode, and first torsional mode are most sensitive to the longitudinal bending stiffness of the side tower, central buckle, vertical bending stiffness of the stiffening girder, and torsional stiffness of the stiffening girder, respectively. The research findings and relevant conclusions can provide basic data for response analysis of long-span TSSBs under dynamic loads and offer an engineering reference for the design of similar bridges around the world.

scholarly journals Dynamic Characteristics Analysis and Experimental Verification of Long Span Suspension Bridge

2021 ◽  
Vol 272 ◽  
pp. 01019
Author(s):  
Guojun Yang ◽  
Qiwei Tian ◽  
Guangwu Tang ◽  
Longlong Li ◽  
Su Ye ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Vibration Frequency ◽  
Natural Vibration ◽  
Structural Parameters ◽  
Great Influence ◽  
Suspension Bridge ◽  
Natural Vibration Frequency ◽  
Vibration Modes ◽  
Dead Load ◽  
Long Span

The dynamic characteristics of long-span suspension bridges are complex. The natural vibration frequency is changed with different structural parameters, and the sensitivity to different parameters is different. In order to solve this problem, the spatial model of a long-span suspension bridge was established by using finite element software, and the first 20 natural vibration periods, natural vibration frequencies and vibration modes were analyzed and calculated. The accuracy of the obtained natural vibration frequency data was verified through field tests. Finally, based on the model, the stiffness of structural components is studied by one -factor-at-one-time, and the influence of various variables on the frequency and mode of a certain mode is studied by one-factor-at-one-time method. The results show that different structural parameters have different effects on the vibration frequency. When the stiffness of stiffening girder and main tower is changed, with the increase of stiffness, the variation of frequency mostly presents an upward trend, and the range is large. With the change of the secondary dead load, most of the frequencies decrease first and then tend to be stable. It can be seen from the field test results that the vibration shapes and frequencies measured by numerical simulation and test are close to each other, which can meet the requirements of engineering precision. The stiffness of the main cable and the main tower has a great influence on the modes and periods corresponding to them. The increase of the secondary dead load can reduce the natural vibration frequency of the suspension bridge, but it is not unlimited to increase the secondary dead load to reduce the frequency. The stiffness of the stiffening girder has a great influence on the frequency of the suspension bridge. When the bending stiffness of the stiffening girder increases to 3 times of the original one, the order of vibration modes of the structure will change. The research results can provide references for structural design and dynamic parameter adjustment of long-span suspension bridge.

Flutter Stability of a Long-Span Suspension Bridge During Erection in Mountainous Areas

2020 ◽  
Vol 20 (09) ◽  
pp. 2050102
Author(s):  
Xingyu Chen ◽  
Ruijie Hu ◽  
Haojun Tang ◽  
Yongle Li ◽  
Enbo Yu ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Structural Characteristics ◽  
Suspension Bridge ◽  
Mountainous Areas ◽  
Structural Dynamic ◽  
Long Span Bridges ◽  
Aerodynamic Shape ◽  
Finite Element Software ◽  
Long Span ◽  
Structural Dynamic Characteristics

In mountainous areas, more challenges are expected for the construction of long-span bridges. The flutter instability during erection is an outstanding issue due to flexible structural characteristics and strong winds with large angles of attack. Taking the suspension bridge as an example, the flutter stability of the bridge with different suspending sequences was investigated. First, the dynamic characteristics of the bridge during erection were computed by the finite element software ANSYS, along with the effects on flutter stability discussed. Then, different aerodynamic shapes of the bridge girder during erection were considered. The aerodynamic coefficients and the critical flutter state were determined by wind tunnel tests. Based on the above analysis, some structural measures are proposed for improving the flutter stability of the bridge during erection. The results show that the flutter stability of the bridge during erection is related to the suspending sequence and the aerodynamic shape of the girder. Owing to the structural dynamic characteristics, the bridge has better flutter stability when the girder segments are suspended symmetrically from the two towers to the mid-span. Considering the construction requirement that the bridge deck should be laid without intervals, this structural superiority is seriously weakened by the unfavorable aerodynamic shape of the girder. In order to improve the flutter stability of the bridge during erection, an effective way is to adopt some temporary structural strengthening measures.

Parameter effects on the dynamic characteristics of a super-long-span triple-tower suspension bridge

2010 ◽  
Vol 11 (5) ◽  
pp. 305-316 ◽  
Author(s):  
Hao Wang ◽  
Ke-guan Zou ◽  
Ai-qun Li ◽  
Chang-ke Jiao
Keyword(s):  
Dynamic Characteristics ◽  
Suspension Bridge ◽  
Long Span

Dynamic Characteristics Analysis and Parametric Study of a Super-Long-Span Triple-Tower Suspension Bridge

2012 ◽  
Vol 256-259 ◽  
pp. 1627-1634 ◽  
Author(s):  
Jia Wen Zhang ◽  
Wen Hua Guo ◽  
Chao Qun Xiang
Keyword(s):  
Dynamic Characteristics ◽  
Suspension Bridge ◽  
Torsional Stiffness ◽  
Mode Shapes ◽  
Suspension Bridges ◽  
Box Girder ◽  
Long Span ◽  
Steel Box Girder ◽  
Elastic Restraints ◽  
Central Buckle

Based on the Taizhou Yangtze River Bridge, a 3D finite element model is developed to establish its deformed equlibrium configuration due to dead loading. Strating from deformed configuration,a modal analysis is performed to provide the frequencies and mode shapes. The study focuses on the effects of the vertical, lateral and torsional stiffness of the steel box girder, the rigid central buckle and the elastic restraints connecting the towers and the steel box girder on the dynamic characteristics of the triple-tower suspension bridge. The results show that, variation of vertical, lateral and torsion stiffness of stiffening girders have effects on the vibration frequency in corresponding directions only and have little effects in other directions. The elastic restraints have a more significant effect on the dynamic characteristics than the central buckle, and decreasing the stiffness of the elastic restraints results in the appearance of a longitudinal floating vibration mode of the bridge. The results obtained could serve as a valuable numerical reference for analyzing and designing super-long-span tripletower suspension bridges.

Control of Vibrations due to Moving Loads on Suspension Bridges

2006 ◽  
Vol 11 (3) ◽  
pp. 293-318 ◽  
Author(s):  
M. Zribi ◽  
N. B. Almutairi ◽  
M. Abdel-Rohman
Keyword(s):  
Bridge Deck ◽  
Suspension Bridge ◽  
Lyapunov Theory ◽  
Dynamic Responses ◽  
Suspension Bridges ◽  
Control Force ◽  
Moving Loads ◽  
Hydraulic Actuator ◽  
Long Span ◽  
Suspended Cables

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.

Numerical Analysis on Buffeting Performance of a Long-Span Four-Tower Suspension Bridge Using the FEM Model

2021 ◽  
Vol 25 (3) ◽  
pp. 854-865
Author(s):  
Hao Wang ◽  
Zidong Xu ◽  
Min Yang ◽  
Tianyou Tao ◽  
Jianxiao Mao ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Suspension Bridge ◽  
Fem Model ◽  
Long Span
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