Research On Collapsed Mechanism Of Single Column Pier Beam Bridge Under Offset Load

Single column pier beam bridge is widely used in highways and upright pivots because of its structural advantage and low cost.But with the increase in vehicle overloading,single column pier beam bridge overturning phenomenon appears more and more serious.This thesis makes a systematic research on the mechanism of overturning failure for the box girder of single column pier beam bridge under overload and partial load of Chunhui Bridge,and proved factors of single column pier beam bridge overturning,which has good theoretical and practical significance engineering to single column pier bridge beam design and reinforcement of anti overturning.This thesis researched three aspects as follow:(1)The two key state before box girder occurs overturning are defined,that is the disengaging state of one side end bearing and the ultimate state of overturning stability.On this basis,the three stages namely stable stage,transitional stage and overturning stage are futher defined;(2)On the background of Shangyu Chunhui Bridge,research the collapse order of Chunhui Bridge and overturning axis position of single column pier beam bridge.(3)The load corresponding to two key states is determined,and further research is made on the relationship between overturning ultimate load and elastic modulus of box girder,load position,bridge length and friction coefficient of bearing and box girderThe results indicate as follow:(1)The overturning ultimate load calculated by finite element simulation conforms well to the measured load in the collapse site of Chunhui Bridge,and the collapse is originated from the box girder overturning firstly,then the pier is torn down;(2)For linear single column pier beam bridge,axis of rotation is located at the bottom edge of the bearing position 45° upward diffusion;(3)the rotating ultimate load and the ultimate overturning load of single column pier beam bridge are related to elastic modulus of box girder,load position and bridge length,and has nothing to do with friction coefficient of bearing and box girder,summarize load calculation formula for overturning...