Experimental Study On Vibration Abutment Of Gravity Pier For New Steel Grid Reinforced Railway

According to the previous seismic data statistical research,bridge earthquake damage is mostly concentrated in the substructure,especially on the pier.Few reinforced concrete gravity piers(??0.5%)are widely used in high-speed railway bridges in China,and the seismic failure is between ductility and brittleness.Reinforcement methods such as concrete,steel plate and carbon fiber cloth can improve the strength but the energy dissipation capacity is relatively insufficient,and the reinforcement cost is high.This paper presents a defensive anti-seismic reinforcement device using reinforced mesh to reinforce railway concrete piers with less reinforcement.Based on the research background,the seismic response of the piers before and after reinforcement under different strength seismic loads is studied by combining the vibration table test with finite element numerical simulation.(1)Reading a large number of relevant literature at home and abroad,summarizing the limitations of using traditional methods to reinforce railway gravity piers,and putting forward a new type of reinforcement device,which can not only improve the strength but also take into account its ductility,and the reinforcement materials are simple and easy to purchase and easy to popularize.(2)It is found that the crack section of reinforced concrete reinforced pier is still at the bottom of the pier under the small and medium-sized earthquake,and the main failure crack is not transferred upward.Under the 8 degree rare earthquake action,the pier bottom crack is completely through,the pier lift off phenomenon.The lift-off phenomenon and crack width of the reinforced pier decrease obviously compared with the unreinforced pier,and the reinforcement effect of three-layer grid reinforcement is generally better than that of two-layer reinforcement.in general All three model piers have bending failure in the plastic hinge distribution area,which indicates that the concrete pier with 0.2% reinforcement ratio has certain ductility,and a small amount of plastic deformation occurs in the plastic hinge area.(3)The seismic response such as acceleration,displacement and strain at the bottom of the pier is studied by testing the vibration table of concrete gravity pier with less reinforcement.The results show that the displacement response of the reinforced pier obviously decreases,the acceleration response increases,and the strain response of the concrete pier bottom decreases.Reinforcement of gravity pier with reinforced mesh can enhance its seismic capacity,and the number of mesh layers has an effect on the seismic response of the pier.The more the number of holes does not affect the strength of the pier,the better the seismic characteristics.(4)Using ABAQUS software,the finite element model of reinforced concrete pier is established.The results are compared with the test data of shaking table.It is found that the variation trend of seismic response such as displacement response,acceleration response and dynamic magnification factor of pier is in good agreement.