Study On Wind-resistance Behavior Of Rotation Constructed T-shaped Rigid Frame Bridge

With the vigorous development of bridge construction technology, a variety ofunique construction technology was invented. Rotation construction is one of them, itsolves the difficult of obstruct the original traffic in construction. However, as thetechnology matures, the bridge span grows, and the structural become more and morelightsome. They are more susceptible to the action of wind. Before the T-shaped rigidframe bridge swivel, we need to remove the construction falsework. Then the bridgeis in a large cantilever state, with small stiffness. It has poor stability under the actionof wind. This paper analyzed the wind resistance performance of the T-shaped rigidframe bridge combine with the Beijing-Baotou railway separate package overpass inJining, Inner Mongolia. Considering the bridge site in a place with big wind velocity,this paper has great practical significance and provides lots of theoretical value toother researchers. The main content and results of this paper are as follows:(1) Using programming software MATLAB and employing the ARautoregressive model to simulate the fluctuating wind velocity time history,obtained the transverse wind velocity time history vurves and vertical windvelocity time history curves of all simulation points. Also a spectralcorrelation test was conducted and proved the reliability of the simulationspectrum.(2) On the basis of computational fluid dynamics theory, using FLUENT and itspre-processing software GAMBIT established a two-dimensional model ofthe girder sections. Then calculated and extracted the static coefficients ofthree components under different wind attack angle, and analyzed itsvariation.(3) Using the Beijing-Baotou railway separate package overpass as anengineering example, this paper established its rotation constructed T-framefinite element model through ANSYS, contrasted the dynamic characteristicsof the largest cantilever state with it of the finished bridge state. Because inthe largest cantilever state, the bridge has smaller stiffness and poorer stability,we judge it as the most unfavorable condition. The static gust response of thebridge is analyzed on this working condition, and the maximum internal forceand displacement were got.(4) According to the fluctuating wind velocity time history, the buffeting force istimed. The aerodynamic force was separated into static wind force, buffetingforce, self-excited force loaded on the structure. Then conducted the timedomain buffeting analysis of the rotation constructed T-shaped rigid framebeam section, got the time history displacement response curve.According to the results of this paper, the rotation constructed bridge is almost controlled by the first three models, and the most unfavorable condition is the largestcantilever state. From the result of the static gust response analysis, we can find therole of wind load can not be ignored. Contrasted the time domain buffeting analysiswith the static gust response analysis of their maximum displacement. The maximumdisplacement in the time domain buffeting analysis was found8.2percent smallerthan that in the static gust response analysis, indicating that using the static gustresponse analysis for wind resistant design is partial security.