| With the rapid development of the economy and the improvement of people’s quality of life,the tourism industry has developed rapidly and the pace of construction of scenic spots has accelerated.More and more glass landscape footbridges that has the function of communicating garden roads,viewing platforms and amusement facilities are built on cliffs and seaside resorts with complex wind conditions.Large windward area,light weight,low rigidity,low damping and low self-vibration frequency are the characteristics of such bridge structures.The natural frequency of the bridge structure is getting closer to the superior frequency of the wind,and the wind-induced vibration of the bridge is prominent.The wind load once became the control load for the design of such bridges.At present,most of the wind-resistance research of bridge structures at home and abroad is for ordinary concrete box girder bridges,concrete-filled steel tube arch bridges,etc.There is less research on wind resistance of pedestrian bridges.The research structure of this subject is the only all-steel space grid glass arch bridge in China.There is little research on the wind resistance performance of this special structure.The body shape coefficient and wind vibration coefficient of this type of arch structure are not given in the specification.Therefore,it is impossible to provide a basis for design.In this paper,based on the bridge wind engineering and fluid mechanics theory,the mesh size,turbulence model and wall roughness are taken as variables.According to the simulation results,the influence of different parameters on the numerical simulation results is qualitatively obtained.According to the analysis,as the wall roughness increases,the vortex of the leeward surface increases,and the wind suction of the leeward surface of the building increases.When the turbulence model is selected as SST k-w and the wall roughness is 0.1,the numerical simulation agrees well with the experimental results.Based on FLUENT software,the elliptical,circular and rectangular cross-section arch bridges are numerically simulated,and the body shape coefficients of each type of structure are given.The influence of the convex top view platform on the wind load characteristics of the structure surface is studied.From the perspective of body shape,it can be seen that the best wind resistance is flat ellipse,then round and rectangular;the existence of the vault sightseeing platform can effectively reduce the wind suction of the upper and lower sides of the arch,especially for the vicinity of the platform obvious.The pulsating wind speed time history data is obtained by using MATLAB programming.Using the time domain method,the finite element analysis software ABAQUS is used to analyze the wind-induced vibration response of the space grid arch bridge.It is suggested that the wind-induced vibration coefficient of the structure is 2.0.Finally,the comfort of the footbridge is evaluated,and the acceleration limit of the landscape footbridge can be appropriately relaxed to 0.3m/s~2.In this paper,the research on the surface wind pressure characteristics and wind-induced vibration response of spatial grid arch bridges provides a reference for the formulation of relevant standards for such structures and the wind-resistant design of structures,and expands the application of wind load simulation of structures in computers.. |
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