Study On Seismic Behavior Of New High-rise Railway Piers

China has a vast territory and complex terrain,especially in the high-intensity mountainous areas such as the southwest and northwest.The high pier bridge has been widely used.Based on the design concept that the main components are damaged after the earthquake and the secondary components can be repaired or replaced,a new type of railway high pier structure was proposed in this paper.The new high pier is mainly composed of four pier columns(main components),the longitudinal and transverse coupling beams(minor components)in pier columns.The elastoplastic analysis of the high pier transverse bridge was carried out by the Incremental Dynamic Analysis(IDA)method,and its seismic performance was studied.The main work done in this paper is as follows:(1)Through the research status at home and abroad,this paper introduces the outstanding problems in the study of traditional high pier structure and seismic performance,and proposes a new type of railway high pier structure,which can be repaired or replaced based on the damage of secondary components after the earthquake.A new type of steel truss coupling beam is used as a secondary component.(2)Based on the Zongmugou Bridge,a new nonlinear finite element model of the high-rise railway bridge was established based on the OpenSees platform.The earthquake damage mechanism of the new high-rise railway pier was revealed and the location where the most unfavorable failure bar of the secondary components was found by IDA method.(3)The influence of the variation of the parameters of the abutment bar of the high pier diagonal cross bracing and the secondary members on the seismic response was studied.The results show that the diagonal transverse bracing has little effect on the internal force of the high pier body;increasing the cross-sectional area of the abdomen bar of the secondary component can significantly reduce the internal force of the pier.(4)By changing the connection mode of the steel truss coupling beam and the high pier column,the yield variation of the steel truss coupling beam and the internal force of the pier column are examined.(5)Explained the action mechanism of the lastic-plastic coupling beams in the new high-rise pier structure.The lastic-plastic coupling beams yield has little effect on the internal force of the pier in the lower part of the pier.The maximum affected area occurs at the position of the pier near the second row of steel truss beams.The plastic elements of the second and third row of steel truss girders can effectively reduced the internal force of the key section of the pier.