Research On Dynamic Characteristics Of The Continuous Concrete Curved Box Girder Bridge Under Vehicle Loads

In recent years, a large number of bridges and other infrastructure produced with the rap-id development of China’s transport services. The curved Bridge can be well adapted to thevariety of routes limit and meet people’s requirements of its beautiful apperarance. Due to theunique design of the curved bridge, its structural characteristics were different from thegeneral linear beam. At the same time, the design, the construction and the maintenance of thecurved bridge become very difficulty. Therefore, its particularly important to study thestructure and mechanical characteristics of the curved beam bridge. The Research of theoutside vehicle loads has become the most important research projects of such bridge. In viewof this, the paper will study the dynamic characteristics of the curved girder bridge which hasthe box-section changes under the vehicle load.The main work and results were as follows:(1) Established the models of the three-span continuous curved box girder bridge with t-he Solid65solid elements and Beam189beam elements of the finite element analysis softwareANSYS. Use the modal analysis to calculate the models, get its first six modes and frequencyand compared this results with the actual measured data. It shows that both of this twoelements can good simulation the real bridges,and the beam element will save more modelingand computing times.(2) Based on the assumption of rigid body dynamics and kinematics of the vehicle, detai-ling describes the derivation of dynamic equations. Based on the actual vehicle, detailing des-cribes how to simplified the model to two degrees of freedom model, then derivation the vibr-ation equation of the simplified models to obtain the formulation of the natural frequency ofthe Undamped free vibration vehicle model and verify it with Dong Feng truck EQ1168G1.(3) Because of the roughness of the actual deck, the vehicle which travel in the deck maygenerated vertical vibration affect and eventually applied to the deck though its wheels.In thisarticle, the actual bridge will be approximate to a sine curve, then take this curve function intovibration equation and obtain the calculation formula of vehicle dynamic load on the deck w-hich caused by the roughness of the deck. Study the impact on the dynamic load of the deckwere caused by the vehicle in different amplitude, different wavelength, and different drivingspeed, and get some conclusions, which may reduces the difficulty of doing a similar problemof axle coupling.(4) Study the changes of the internal force and displacement response of the curved brid-ge as the radius of curvature, the vehicle eccentricity and the vehicle speed changes under the previous calculation formula of the vehicle dynamic load. Then get some useful conclusions,provide a reference for further exploration axle coupled dynamic problems.