Time-Domain Buffeting Analysis Of Long-Span Cable-Stayed Suspension Bridge Under The Action Of Non-Stationary Wind Field

With the improvement of people’s living conditions and the increasing social demand,people’s aesthetic standards of architectural structure are also improving.As a new type system of bridge,cable-stayed suspension bridge has a unique and graceful structure,which can be regarded as a landmark building.For the long-span cable-stayed suspension bridge,its wind-resistance performance is often highly concerned,however,there are few studies on its related wind vibration.Generally the wind field is considered as a stationary stochastic process in the buffeting analysis of long-span bridges.However,the wind speed characteristics of bridges in complex terrain or strong wind environment show non-stationary characteristics.Therefore,it is more important to study the wind-vibration response and the stability of the long-span cable-stayed suspension bridge under the action of non-stationary wind field in a complex environment.In this thesis,a double-tower cable-stayed suspension bridge of cooperation system with a main span of 1488 m is taken as an example to study the buffeting response under the action of non-stationary wind field.The corresponding span arrangement is70m+84m+434m+1488m+434m+84m+70m,and the width of the steel-box girder is 54.2m,and the height is 5.1m.First of all,according to the wind speed data at the bridge site,the relevant parameters of fluctuating wind are selected.Based on the evolutionary spectrum theory and parameter optimization of the modulation function,the improved combination of the wave superposition method is used to simulate the non-stationary wind fields,and the relative parameters are verified and compared with the wind speed parameters of the stationary wind field.Then,according to the design data,the finite element model of cable-stayed suspension bridge is built in ANSYS,the structural dynamic characteristics are calculated,and the natural vibration frequency is obtained.Then in the CFD numerical wind tunnel,the static three-component force coefficient and the aerodynamic admittance function of the girder are numerically identified,and the aerodynamic parameters of the girder are obtained.Finally,making time domain treatment on non-stationary buffeting force and self-excited force,and then uploading them with static wind force to the finite element model to carry out buffeting time domain analysis.At the same time,the buffeting response of cable-stayed suspension bridge under three different aerodynamic admittance functions、five different wind attack angle and the consideration of self-excited force is calculated,and the buffeting response of the bridge under different parameters is analyzed.