Study On Wind-induced Vibration Of Lone-Span Suspension Bridges

Suspension Bridge is one of the oldest bridge, which has a long history, Suspension bridge across the largest capacity of all bridge type and the bridge which span above1000m almost all suspension bridges, However, until the early twentieth Century, because the cable material and technological progress, and gradually rise of long-span suspension bridges, and the continuous development.In the Tacoma bridge due to wind-induced vibration after the destruction, many experts and scholars have put it destroyed due to the static wind action.However, many scientists around the world in the investigation of bridge damage in the process, found that, after1818, there are a lot of suspension bridge is destroyed by the wind vibration.Since then, wind induced vibration of suspension bridge is becoming more and more attention by the people.From the basic theory of wind resistance of bridge (bridge flutter, buffeting) build, to modern bridges theory development theory, including bridge flutter buffeting theory development, computational fluid dynamics (CFD) technology and reliability based design method for the development of.Wind resistance of bridges at home and abroad the theory through several generations of scientists and scholars in the research and development, has reached a certain theoretical level.This paper firstly expounds bridge wind induced vibration theory, introduces the flutter, galloping, buffeting, vortex-induced resonance of the related concept, on the basis of this, a large span suspension bridge wind numerical simulation analysis, the main work includes the following three points:(1) Application of ANSYS/CFD finite element software, some of the section three analysis of static aerodynamic coefficients, respectively analyzes the blunt head box girder with cantilever box girder, with diagonal web box girder, box girder, flat four section type, and the four types of beam type in0degree wind attack angles under static three aerodynamic force coefficients were compared, find, flat box girder section pneumatic performance is good, however, stiffening steel truss girder with large stiffness and good ventilation rate, wind resistance performance is good, therefore large span suspension bridge is the use of this form of section.(2) On the main span of500m suspension bridge model FEM static and dynamic analysis.And the static stability analysis.Using dynamic analysis results, on bridge flutter stability checking, discovery: torsion coupled flutter and separated flow torsional flutter critical wind speed were less than girder flutter test wind speed, wind does not meet safety requirements, it is necessary to wind-induced vibration control measures.(3) A general introduction to wind-induced vibration control measures include:structural measures, aerodynamic measures and mechanical measures.This article mainly aims at the structure measures for analysis, respectively adding rigid horizontal wind cable, the main span of1/4to set up cross diagonal cable truss, increase width, with a single main cable triangle inclined hangers and the spatial main cable and other measures to improve the bridge wind resistance performance, finally, from economy, beautiful, the difficulty of construction, technology innovation consideration of multiple perspectives, the final choice of the structure measure used is the spatial main cable of the measures to improve the bridge wind resistance, improving the wind resistance stability.