Wind-resistant Safety Research For High Pier And Long-span Continuous Rigid Frame Bridge During Cantilever Construction Period

In recent years, along with the advancement of the western development strategy, long spancontinuous rigid frame bridge with high piers of its unique advantage of the west in the western region hasbeen widely used. In the western region are very complex landform and physiognomy mountain valleys, itswind characteristic is very complex. At present, in view of the western region of large span bridge windresistance studies is relatively small, with the increase of pier height and cantilever elongation, securityproblem in the process of cantilever construction urgent research subject, this article, which is based on awestern region example project, carried out the following work:First of all, investigate and study the distribution of landform and physiognomy of the westernmountains, on the basis of simple introduces the mountain valleys terrain environment influence to thewind and the wind field characteristics of the region in detail in this paper. Bridge and combined with theproject of topographic features, set up "virtual observatory", using the least squares method of bridge site ina few stations near the recurrence period of wind speed and altitude for fitting, draw a return period of thegrowth rate of velocity and altitude. Using distance and terrain block double weighted wind speed ofinterpolation method to calculate draw a "virtual observatory" basic wind speed, considering the terraincorrection coefficient, the mountain valleys and calculates the wind resistant design wind speed for relyingon the project are very place.Secondly, the dynamic characteristics of long-span continuous rigid frame bridge with high-rise pierswere analyzed, and concluded that the most unfavorable loading state of structure for the structure of the Ttype rigid frame of the maximum double cantilever stage. Recycling has been calculated in front of thebridge wind resistance design of the wind speed, static on the structure of the maximum double cantileverstate of gust wind resistance analysis, analysis of structure under different loading conditions with thebottom of the pier structure cross section beams and the root of the internal force distribution, at the sametime on the structure of the state of flutter analysis.Finally, a brief introduction at present commonly used vibration comfort evaluation index, the windload calculated according to the value at every stage of the cantilever construction and structure vibrationfrequency. Using Midas/civil2010finite element model is established, using the simplified dynamic loadingin the form of repeated load time history analysis of structures. With high piers, cantilever length and windspeed as parameters, analysis of the structure under the action of dynamic load, displacement and acceleration of the trend. With Diekemann comfort evaluation index, the index K and acceleration vibrationcomfort evaluation analysis of the structure. Then on the basis of the above evaluation of fruit, temporarywind resistance to currently available in cantilever construction measures according to the engineering fieldbased on comparative analysis, ratio choose the best temporary measures to wind resistance.