Abstract

An aerodynamic optimization measure of the flutter stability of long-span suspension bridges with truss girder is presented in this paper. At first, the improvement of several kinds of central stabilizers and horizontal stabilizers on flutter stability is examined through series of section model and full aeroelastic model wind tunnel tests. Subsequently, the flutter derivatives of the truss girder with and without stabilizer are identified based on two degrees of freedom coupling free vibration method. Furthermore, based on the identified flutter derivatives, the critical flutter velocities of the truss girder section with and without stabilizer are analyzed through two dimensional flutter analysis method and the critical flutter velocities of the full bridge with and without stabilizer are analyzed through three dimensional method. Afterwards, the influence of each flutter derivative on the flutter stability of the truss girder is investigated. The results indicate that central upper stabilizer can effectively increase the critical flutter velocity of the truss girder. In contrast, the central lower stabilizer and horizontal stabilizer have less influence. Setting up central upper stabilizer leads to an obvious decrease in the value of the flutter derivatives A2* and H2*, while the flutter derivatives H1*, H4*, A1* and A3* are little influenced. The two dimensional and three dimensional flutter analysis results agree well with the sectional model and full model wind tunnel test results respectively.

Highlights

  • Steel truss girder is one of the major types of main girders of the suspension bridge in mountainous regions due to its large torsional stiffness, high ventilation ratio, suiting for complex wind environment, convenient transport and assembly

  • Wang tested the effect of the central upper stabilizer, central lower stabilizer and horizontal stabilizer on the flutter stability of truss girders based on three different types of truss girder of suspension bridge

  • The result clearly shows that the critical flutter velocity at –3° wind attack angle is higher than the flutter checking velocity according to the specification JTG/TD60-01 [11], while the critical velocities at 0° and +3° wind attack angle are lower than the checking velocity

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Summary

Introduction

Steel truss girder is one of the major types of main girders of the suspension bridge in mountainous regions due to its large torsional stiffness, high ventilation ratio, suiting for complex wind environment, convenient transport and assembly. Liu investigated the flutter stability optimization effect of sealing the central slot, central upper stabilizer and central lower stabilizers through sectional model wind tunnel test. The test results show that central slot reduces the critical flutter velocity of the truss girder section; the central vertical stabilizer can improve the flutter stability; the horizontal stabilizer has little effect on the flutter performance [8]. Wang tested the effect of the central upper stabilizer, central lower stabilizer and horizontal stabilizer on the flutter stability of truss girders based on three different types of truss girder of suspension bridge. The study shows that the different aerodynamic optimization solutions applied to distinct truss girders section [9, 10] All of these studies suggested that installing appropriate stabilizers could suppress the wind-induced oscillation and improve the flutter stability of truss girder suspension bridges. The influence of each flutter derivative on the flutter stability of the truss girder is investigated

Dynamic characteristic analysis
Sectional model tests
Sectional model and experimental setup
Data processing
Experimental results
Flutter performance optimization
Central lower stabilizer
Central upper stabilizer
Horizontal stabilizer
Flutter derivatives identification
Identified results
Full aeroelastic model test
Theoretical background
Analysis result
Influence of each flutter derivative
Conclusions
Full Text
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