Research on the Mechanical Properties of Railway Bridge Strengthened with Quick- composite Reinforcement Methods

Research purposes: The lateral stiffness and load- bearing capacity of existing 32 m simply- supported concrete T- beam railway bridges fail to meet the needs because of train speed raising and development of heavy train.In order to solve these problems,the quick reinforcement methods that use external prestressing tendons and precast concrete diaphragm plate are studied. Dynamic interaction between train and bridge is studied through ANSYS and multi- body dynamics software UM.Research conclusions:( 1) Results of the vehicle- bridge simulation indicate that the main problem of the existing bridge when high- speed train pass through is the lateral amplitude of vibration is too large,lateral reinforcement can effectively improve the lateral stiffness and enhance univalent lateral natural vibration frequency and univalent torsion natural vibration frequency.( 2) The main problem of the existing bridge when heavy train passed through is the poor load- bearing capacity and the excessive vertical deflection. Vertical reinforcement can improve the load- bearing capacity and univalent vertical natural vibration frequency,at the same time it will lead to the beam's lateral vibration frequency becoming smaller. So lateral reinforcement and vertical reinforcement should be done at the same time.( 3) The validity of vehicle- bridge system's resonance principle and the reliability of resonance response of thereinforcement bridge are all confirmed.( 4) After reinforcement the dynamic responses of bridge and train can meet requirements of relevant regulation.( 5) This reinforcement methods can be used for the existing railway concrete simply-supported beam bridge when time is very tense and the railway operation can't be interrupt.