Study On Mechanical Behavior And Technological Characteristics Of Lightweight Aggregate Concrete Frame Bridge

Frame bridge structure is widely used in modern transportation system to achieve the separation between the railway and highway.It can speed up transportation and improve traffic efficiency.But due to its excessive weight,it increases the difficulty and danger of the construction,and poses a safety hazard to the normal operation of the railway.Considering the advantages of lightweight concrete with high quality,this paper based on the engineering examples and introduced lightweight aggregate concrete into frame bridge.Then the paper compares the stress performance,self-vibration characteristics and seismic dynamic response rule of ordinary concrete and light aggregate concrete frame bridges.In view of the construction characteristics of frame bridge structure,it analyzes the advantages of the process performance of lightweight aggregate concrete structure.The main conclusions are as follows:(1)According to the field jacking test of the frame bridge,it is found that the middle span deformation of the frame bridge structure is the biggest,and the deformation on both sides is smaller.The jacking process has a great influence on the normal operation of the railway.(2)Under the static load,the internal force and deformation of the lightweight aggregate concrete frame bridge are different from the ordinary concrete frame bridge structure,but they can still meet the requirements of the code.(3)The two structures have different modes of vibration and cycle.Because the elastic modulus of the light aggregate concrete is smaller than the ordinary concrete,the structure in modal analysis is greater than the normal concrete structure under the same intensity.(4)Under the seismic load,deformation and acceleration of lightweight frame bridge structure are less than common frame bridge structure,at the same time,stress concentration of the common frame bridge structure is more obvious than the lightweight aggregate bridge structure,and more likely to damage,so the lightweight aggregate frame bridge structure has better seismic performance.(5)Lightweight aggregate concrete structure can reduce the weight of structure,reduce the jacking force required for jacking,it can reduce the jacking friction resistance,shorten the jacking cycle,improve the operation efficiency of the railway and save the project cost.It has better process performance.