Anti-Overturning Stability Analysis For Curved Girder Bridge With Single Column Pier

In our country, with the continuous development of transportation industry and the speeding up of urbanization, more and more curve beam bridges which adapt to the change in road alignment is built. In some ramp bridges design of highway and city road overpass intersection, due to the small space under the bridge and the narrow bridge width, designers usually design these ramp bridge into a single column pier support form. Due to the beautiful line and cover an area of small, this kind of single column pier curve girder bridge is used widely.But recently, some bridge overturn accidents happened in our country. Single column pier bridge occupied a large proportion in these bridges. Because most of the designers focus on the longitudinal force performance of the bridge structure at design time, and ignore the transverse anti-overturning stability of the bridge, so the overturn accidents happened frequently of this bridge which has poor ability of anti-overturning stability. So, based on the single column pier curve bridge as the research object, for its anti-overturning stability to carry out the following research work:1. The coefficient of anti-overturning stability of single column pier curve girder bridge which located in Changchun south expressway is calculated based on the latest specification, and the ramp bridge anti-overturning stability is analyzed. Then calculate the bridge maximum load according to the drawing soil car which frequent appears in the accident, to prevent the ramp bridge overturn accidents in the serious overload vehicle.2. Then analyze the five factors which affect the single column pier curve girder bridge resist overturning stability, including the bridge radius, the distance of double pedestal piers of side piers, the eccentricity of the block in the single bearing, the length ratio of the side span and across span and the bridge longitudinal slope, get the five main factors influencing regular on the anti-overturning stability of single column pier curve beam bridge.3. Calculate the correlation of the five factors about overturning stability coefficient through the theory of grey correlation analysis method, sort of factors through the theory of grey correlation analysis method, get the influence degree to the resist overturning stability. In view of the influence degree maximum two factors, the length ratio of the side span and across span and the distance of double pedestal piers of side piers, put forward relevant suggestion for designers reference. In order to improve the anti-overturning stability of the bridge.4. The anti-overturning stability of single column pier curve girder bridge is predict through BP neural network and SVM. According to the results of grey correlation analysis, the three biggest influence degree factors is the length ratio of the side span and across span, the distance of double pedestal piers of side piers and the bridge radius. First of all, according to three main factors, with 75 groups of examples for training the neural network and the SVM model, set up the nonlinear relationship between the three factors and the anti-overturning stability coefficient. Using the trained model to predict the coefficient of anti-overturning stability, the predicted results and the actual results are basically identical, the precision of SVM is higher then BP neural network. Both of them have a certain engineering value to anti-overturning stability analysis of single column pier curve girder bridge.