Vibration Reduction Of Train-track-bridge Structure Using Ruberized Concrete Slab Track

Rubberized concrete contains scrap rubber as a replacement to natural aggregate,serving as a possible solution to deal with waste tires.Impact loads from trains in operation induce vibration on bridge structure and its surroundings,which causes track-bridge deterioration and negative environmental effects.To investigate the potential of using rubberized concrete as track slab on subway elevated bridge,the finite element analysis and train-bridge coupling theory are used.First,mechanical properties of ordinary concrete track slab and rubberized concrete track slab with15% and 25% rubber content are derived for establishing ANSYS Workbench model.These models are analyzed and compared by considering the parameters of subway train type,train speed,train traffic direction and rubber content.Transient structural analysis is performed in all study cases to obtain its dynamic response.The dynamic results are analyzed in frequency domain by using Fast Fourier transform,and the effect of vibration reduction is compared.The bridge-track structure subjected to moving train loads through a bridge span of 32 m is analyzed and the vibration responses of the bridge-track structure are obtained in both time and frequency domains.The results show that: the peak acceleration of the bridge with rubberized concrete track slab in all cases are lower than that of ordinary concrete track slab,which implies rubberized concrete track slab has better vibration attenuation capacity when compared to ordinary track slab.In addition,the rubberized concrete track slab has better vibration reduction with speed of 120 km/h and type C subway train.The reduction of bridge acceleration could be attributable to its damping capacity of rubberized concrete which helps to absorb a significant portion of the energy.The Dynamic analysis model of wheel-sprung-mass-bridge system is established to analyze the vibration reduction effect of rubberized concrete track slab on the running safety and comfort of the train.By comparing the offload factor,vertical acceleration and vibration level of car body during the train running through the bridge with different kinds of track slabs,it shows 25% RBC track slab has reduced vibration level by 9.94 d B and vertical acceleration by 26.67%.Similarly,the vibration reduction effect on train type C,is more clear than type A and type B.For train speed,higher the running speed,the better effect of vibration reduction on car body vibration.In general,the rubberized concrete track has a positive effect on the running safety and comfort on the train.