Study On Wind Resistance Stability Of Long-span Pedestrian Suspension Bridge

Suspension bridge is one kind of the world’s most ancient bridges, whose span isalso the largest of all types. The modern suspension bridges’ spans are basically above1000m. After the destruction of the Tacoma Bridge due to wind-induced vibration, theengineers began to pay attention to the wind-induced vibration problem in theengineering design, and launched a series of research on the wind resistance stabilityof bridges.Study on wind resistance stability of long-span suspension bridge mainly focuson the research of bridge flutter stability and the characteristics of bridgevortex-induced vibration. The pedestrian suspension bridge of Zhangjiajie is currentlyin the preliminary design stage. For the considerations of aesthetics, the main girderof the bridge was designed to a blunt body section in the first step. The g irder’sdepth-span ratio is1/641.6667, which is far smaller than the Old Tacoma Bridge’sdepth-span ratio of1/348. And the bridge is softer than the Old Tacoma Bridge. Thepedestrian suspension bridge of Zhangjiajie is also very light.The weight of thebridge is3.933tons per meter. Under the dynamic action of wind, the bridge structureis so light and thin that the wind-induced vibration will become the key factor in thestructure design. Taking the pedestrian suspension bridge of Zhangjiajie as theengineering background in this paper, based on the existing analysis methods of theflutter and vortex-induced vibration, the author used section model wind tunnel test tostudy the wind resistance stability of large-span bridges. The main research contentsof this thesis are as follows:1.After reviewing the development history of the suspension bridge, then thewind-induced vibration phenomena of bridges were briefly introduced. The analysistheory of bridge wind resistant stability were introduced, and the a uthor summed upcountermeasures of wind-induced vibration in three aspects: aerodynamic measures,structural measures, and mechanical vibration measures.2.Combined with the engineering situation of Zhangjiajie pedestrian suspensionbridge, the author calculated the flutter inspective velocity of the preliminary design,analyzed the bridge’s dynamic behavior, and designed the section model and so on.3.Based on the preliminary design scheme of the extraversion type glass railings,8flutter derivatives of three combined aerodynamic measures conditions were identified by wind tunnel test. And so the author established a finite element model ofthe Zhangjiajie pedestrian suspension bridge for flutter analysing, and discussed theeffect of the flutter stability caused by three kinds of aerodynamic measures.4.A preferred aerodynamic section form was presented, and the aut hor thenstudied the wind resistance stability of rigid section model by wind tunnel test ing ofvibration performance, got the results of the flutter stability and vortex excitedresonance characteristics of the stiffening girder after shape being changedaerodynamically.