Study On Seismic Behavior Of Railway Gravity Piers With High Strength Steel Bars

Compared with ordinary steel bar,high-strength steel bar has the characteristics of high strength,energy saving,environmental protection and good seismic performance.However,domestic high-strength steel bars are mostly used in civil buildings and highway bridges,but less in railway bridges.At present,there are few studies on the seismic performance of railway gravity piers with high-strength steel bars,and the effects of different configurations of high-strength steel bars on the seismic performance of railway piers and the failure mechanism still need to be studied.In this paper,the difference of seismic performance of high-strength reinforced railway piers under different reinforcement modes is analyzed by means of quasi-static test and numerical simulation,and the seismic performance of piers is evaluated based on Pushover method.The main research work is as follows:(1)Consulting a large number of related literatures,the current research status of seismic performance of high-strength reinforced piers and less reinforced concrete piers at home and abroad is summarized,the effects of different parameters on the seismic performance index of less reinforced concrete piers are summarized,and the model test methods and numerical analysis methods of different railway piers are compared.(2)Based on the prototype of railway gravity concrete piers,four scale models with different reinforcement ratios and equipped with high-strength steel bars and ordinary steel bars are designed,and the pseudo-static test method is used to study the failure mechanism of railway gravity piers with high-strength steel bars.The results show that the spalling area of the concrete at the bottom of the model pier with high strength steel bar is larger,the phenomenon that the longitudinal bar is broken is more obvious,and the failure characteristic gradually develops to plastic failure.(3)Based on the quasi-static test,the effects of different configurations of high-strength steel bars on the hysteretic curve,skeleton curve,stiffness,energy dissipation capacity and residual deformation of bridge piers are studied.The results show that the hysteretic area,ultimate bearing capacity,energy dissipation capacity and ultimate displacement of the highstrength steel bar model replaced by equal area are obviously improved,and the displacement ductility is slightly reduced.(4)Based on the finite element software Open Sees,the gravity pier model of highstrength steel bar railway is established.The rationality of the model is verified by comparing the numerical simulation results with the test results,and the effects of equal area replacement and equal strength replacement of high-strength steel bars with different reinforcement on the seismic performance of railway piers are analyzed.The results show that the equal strength replacement of high-strength steel bar can reduce the damage of bridge piers under earthquake.(5)Based on the finite element model,the capacity spectrum curve of railway prototype pier and the demand spectrum curve under different seismic intensity are established by Pushover analysis method,and the seismic performance of railway gravity pier with different configuration of high strength steel bar is evaluated.The results show that the seismic design of railway piers with equal strength reinforcement can make the piers meet the requirements of seismic code without increasing the amount of steel bar.