Analysis And Research On Wind Resistance Of Continuous Long-Span Rigid Frame Bridge With High Piers

In recent years,the bridge construction in our country has grown vigorously.With specific superiorities and advanced technology,the continuous rigid frame bridge has become a very popular bridge type and constantly strides forward in the direction of high-pier as well as long-span.Due to its increasing noticeable problem of wind-resistant,especially the smaller stiffness in the maximum double cantilever stage,the continuous rigid frame bridge has been significantly affected by the wind load.Therefore,it is quite necessary to conduct research on the wind-resistant analysis of continuous rigid frame bridge.Based on the Dianzhanerhao Bridge,this paper mainly includes the following contents:(1)In view of the lack of wind speed observation data at the bridge site,the numerical simulation method can be used to obtain the fluctuating wind velocities indirectly.This paper,through the way of linear filtering method and MATLAB,has compared the power spectrum curve of the simulated spectrum and the target spectrum,both of them are fitting well,which shows that it is reasonable and feasible to adopt the method of simulating the fluctuation wind velocity in the absence of the wind speed observation data.(2)With the method of computational fluid dynamics and the software of FLUENT,this paper has calculated three component coefficients of the mid-span section as well as the cantilever root section from different wind attack angles and also extracted the characteristics of flow field distribution.Then,the influence of wind attack angle and section height on the three component coefficients is analyzed.(3)According to the provisions and suggestions of the wind-resistant design code for highway bridges in our country,the design reference wind speed,the design wind speed at the construction stage,the static gust wind speed and the static gust load are calculated.By using the finite element ANSYS software,the model of maximum double cantilever and finished stages in the Dianzhanerhao Bridge is established.Meanwhile,a dynamic characteristic analysis of the two models has been made as well and it is concluded that the most unfavorable stage for wind resistance is the maximum double cantilever stage,there is no need to consider the dynamics of the wind.(4)The wind resistance analysis of the maximum double cantilever stage is separately carried out by using three kinds of adverse static wind loads,and it is found that the effect of static wind load cannot be neglected by virtue of the calculated internal force of cantilever root and pier bottom sections.Then the flutter stability,vortex-induced vibration and galloping stability of the maximum double cantilever stage are analyzed and calculated.The results show that these wind-induced vibration phenomenon will not occur.So the dynamic action of the wind can not be considered.