Numerical Simulation Study On Damping Effect Of Vibration-isolating Slot On Bridge

As an economical and efficient method of isolation and reduction,vibration-isolating slot can reduce the damage caused by blasting vibration.However,the damping effect is affected by the parameters of vibration-isolating slot.How to optimize the parameters of the vibration-isolating slot is very important for the blasting design and construction.In this paper,the finite element software ANSYS/LS-DYNA was used for numerical simulation.The relationship between the damping rate and the parameters of vibration-isolating slot was obtained by changing the vibration-isolating slot parameters.The dynamic response of bridge caused by the blasting seismic wave passing through vibration-isolating slot were compared with the dynamic response without passing through vibration-isolating slot.The effect of vibration-isolating slot on the isolation and reduction of the bridge was analyzed.The following researches were made:Firstly,this paper discussed the research results of the vibration-isolating slot at home and abroad,and analyzed the characteristics of the blasting seismic wave and the damping mechanism.Secondly,the modeling process of ANSYS/LS-DYNA was studied,and the algorithm of structure element was determined.The propagation of blasting seismic wave in rock was simulated under the condition that there is no vibration-isolating slot.It can be concluded that the attenuation law of blasting seismic wave accords with Sadov's Vibration Formula.Thirdly,by changing the material parameters and geometric parameters of vibration-isolating slot,the influence of the parameters on the damping effect was analyzed.And the parameters of vibration-isolating slot were optimized.The following researches can be obtained by numerical simulation: Increasing the length and depth of the damping ditch,as well as,reducing the distance of explosion and damping ditch can improve damping rate,and the change of vibration-isolating slot's width has little influence on the damping effect,water filled in vibration-isolating slot can reduce the damping rate.Finally,the dynamic response of a simply supported girder bridge caused by blasting seismic wave was calculated under the two conditions which include setting the optimal parameters of the vibration-isolating slot and no vibration-isolating slot.It can be concluded that the velocity,acceleration and stress peak of the bridge measuring points are obviously reduced after setting the vibration-isolating slot.The damping effect of the vibration-isolating slot is obvious.