Analysis Of Mechanical Characteristics Of T-beam Bridge Based On Combined Reinforcement

The bridge project occupies an important position in the transportation business and is a structure that crosses various obstacles.After the founding of New China,the national economy was restored and developed.A large number of old bridges were built in the early days of the founding of the People’s Republic of China.In the five-year plan,railway trunk lines,highway network lines,ferries and many important bridges were built.With the acceleration of China’s modernization process,vehicle load,vehicle speed and traffic volume have undergone great changes,which has brought great challenges to the bridges designed according to the old regulations.Except for a few important bridges,a large number of bridges In the past period of lack of maintenance,the repair and reinforcement of old bridges has become a hot research topic in recent years.In this paper,an old railway overpass is taken as the engineering background,and the combination of external prestressing force and steel plate is used to reinforce,and the bearing capacity of the bridge before and after reinforcement is checked.Using MIDAS/civil finite element software to establish the finite element model before and after the reinforcement.Based on the structural dynamics and seismic theory,using the finite element software to analyze the response of the bridge before and after the reinforcement under dynamic load and three different directions of seismic load.The results show that the composite strengthening method based on the bearing capacity is better than the single strengthening method.Compared with the frequency and period of the first five modes before and after the combined reinforcement of the bridge,it shows that the external prestressing has little influence on the section size of the original structure,but after the combined reinforcement,the natural frequency of the bridge increases,and the combined reinforcement makes the overall rigidity of the bridge larger.Through the analysis of the vertical displacement and stress response of the mid span section of the bridge before and after the reinforcement under the moving load,it can be concluded that the combined reinforcement of the bonded steel and the external prestressing has a significant control effect on the vertical displacement and the normal stress of the bridge under the moving load,the thickness and strength of the steel plate have an impact on the dynamic response of the combined reinforcement system,and the dynamic response of the combined reinforcement system follows that of the steel plate The thickness decreases with the increase of steel plate strength.The results show that the peak value of the vertical displacement response in the middle of the bridge is 40%lower than that before,and the peak value of the lateral displacement response is 43%lower than that before;the peak value of the vertical displacement response in the middle of the bridge is 14%lower than that before;the peak value of the vertical displacement response in the vertical bridge is 14%lower than that before;the peak value of the vertical displacement response in the vertical bridge is 14%lower than that before Under the action of load,the vertical displacement response of the mid span section of the composite strengthened bridge is reduced by 30%,the peak value of the lateral displacement response is reduced by 58%,and the peak value of the stress response is reduced by 21%.The combination of bonded steel and external prestressing improves the seismic performance of the bridge.Compared with the simple use of two reinforcement methods,the response to the earthquake is lower,and the seismic capacity of the bridge is improved more,which can make up for the shortcomings of the two reinforcement methods.