| After many years of development,the behavior of rotation on bridge construction technology appeared in the last century has become increasingly important in our social production and life.Usually,bridges are constructed to across rivers,valleys,and existing transportation lines.The use of rotation construction technology can ensure smooth traffic,complete tasks in time,and save budgets.Its economical advantages and social benefits are obvious and have been payed more attention in recent years.Since the reform and opening up,as T-shaped bridges have been growing with higher,wider,heavier and bigger cantilever,the wind-resistant problem of T-shaped bridges in the rotation construction has become more and more prominent.Because of the cantilever and single point support state in the process of the level rotation construction,the T-shaped bridge is easily affected by the environmental wind.So the wind-resistant designs is more necessary for the T-shaped bridge swivel construction.Based on the cross-line swivel project of the Hunshuitang Bridge in Yunnan,and according to the characteristics of the height,width,and weight of the swivel,the effects of the rounded corner and web dip angle of section on the aerodynamic parameters,the responses of the static gust and the dynamic responses of the bridge structure were analyzed,And the influence of the variation of the wind yaw angle of the natural wind field and the change factors of the rotating speed of the main beam on the wind-induced buffeting response of the bridge,which provided theoretical basis for the swivel bridges construction.the main research contents of this paper are showed as follows:(1)Based on the rotation construction of the Hunshuitang Bridge in Yunnan,the engineering cases of the rotation construction were collected,as well as relevant technical data was summerized.Based on the level rotation construction process,which is one of the rotating construction methods,the project profile and the whole construction process were introduced in detail.(2)The simulation parameters were set up with 21 wind speed simulation points on the main beam.The horizontal cross-bridge and vertical fluctuating wind spectra were taken respectively from Kaimal spectrum and Panofsky-Mc Cormick spectrum,and the numerical simulation of fluctuating wind was conducted in MATLAB.The wind speed time series and power spectrum at some points were obtained,which was prepared for correlation analysis to fully verify the reliability of the simulated wind spectrum.(3)Based on the CFD numerical simulation technique,the FURENT analysis software was used to simulate the aerodynamic force and coefficient of tri-component calculation and numerical fitting of the T-shaped bridge cantilever root section.From the aspects of rounded corner ratios of beam section and web dip angle respectively,The influence of the change of geometrical shape of the beam section on the coefficient of tri-component was analyzed,and the flow field characteristics of the sections with different rounded corner ratios and web dip angles were analyzed.(4)The Combin7 spring element in ANSYS was used to establish the ball joint connection part of T-shaped bridge piers bottom,and the modal analysis and static wind load analysis of the structure.based on the quasi-stationary buffeting force model and the elf-excited aerodynamic forces model,The buffeting analysis in time domain of different structural states in the construction of bridge swivel was performed in ANSYS,and the results of the buffeting displacement and internal force response at key positions were obtained.(5)Based results of the static wind response and buffeting analysis in time domain of T-shaped bridges,the effects of skew wind action in the natural wind field,self-excited aerodynamic force,and T-shaped cantilever beam rotation speed change on the buffeting response of the bridge were investigated. |
PDF Full Text Request