Development Of The Bridge Expansion Device With Multidirectional Beam And Plate Joint And Research On The Mechanical Properties

The bridge expansion device is responsible for coordinating the longitudinal displacement of the bridge caused by temperature,concrete shrinkage and creep,live load and so on.The failure of displacement system causes the bridge head to jump and damage the wheels and even traffic vehicles.This paper is aiming at the problems existing in comb plate expansion joint which are difficult to meet the vertical displacement,the installation slotted depth is large,the noise is large,and so on,through finite element numerical simulation,indoor test,field engineering application research,etc.A new type of multi-directional displacement beam-plate chain-type telescopic device is developed.The work and conclusions of the paper are as follows:Firstly,research and development is carried out of multi-directional displacement beam-plate chain-type telescopic device.On the basis of analyzing the defects of existing bridge telescopic devices and combining with the working principle of expansion joints,an innovative composite structure of "tooth plate type cross seam beam" is put forward.Compared with the conventional ones,the structural form of "beam" can realize the displacement of three dimensions in real sense,and meet the requirements of six degrees of freedom of the bridge.The slotted depth are reduced,and with the rubber bearing at the bottom of the beam,the vibration performance and noise reduction ability of the telescopic device are improved.Secondly,the structure optimization is performed of the multi-directional displacement beam-plate chain-type telescopic device.Through the finite element simulation,the connection between the side beam and the span beam is compared and analyzed.The maximum error is only 0.606mm under various modifications of the telescopic device without rotation system,and the type of the elastic element is optimized.The arch elastic element with more reasonable force is selected.The size and structure of the elastic element are optimized by the combination of indoor test and finite element simulation,and the service life is longer.The elastic element of 12mm thickness that matches the force of the whole telescopic device.Thirdly,study is conducted on the mechanical properties of multi-directional beam-plate chain-type telescopic device.The static and dynamic performance of the telescopic device is studied by finite element simulation.The strength and stiffness of the beam,side beam and elastic element are studied.The maximum deflection of the side beam is 1/7500 of the support spacing.The dynamic characteristics and dynamic response of the telescopic device are studied,and the fatigue life of the telescopic device is studied by combining the main materials and its S-N curve.The results show that it is mainly affected by elastic elements.Lastly,study is accomplished on the working performance of the multi-directional displacement beam-plate chain-type telescopic device.The experimental study on the working performance of the telescopic device is carried out,and the field measurement is carried out by relying on the project.The results of test and engineering application show that the working performance of the telescopic device can meet the requirements of multi-direction displacement and noise.