Seismic Analysis And Suggestions Of Single Pillar And Long Cantilever Elevated Station

With the development of rail transit in our country, an increasing number of urban rail transit lines are under construction or to be built. Single pillar and long cantilever elevated railway station is widely used because of its advantages, such as better structural integrity, less land occupancy rate, and higher space utilization. But as a new type of station-bridge structure system, the present study is still not mature enough.Taking Ba Gong Li Station of Chongqing rail transit line 3 as engineering background,this paper have researched the following several aspects of seismic performance of this structural system:Firstly, a simplified whole structure model is established by SAP2000 and ETABS software to study the seismic loading characteristics of single pillar and long cantilever elevated railway station. It is found that the second-order modal of the structure corresponds with torsional vibration; Bending moment of Column at the end of structure was highly sensitive to the transverse direction seismic accidental eccentricity, increased more than 50%; There is a large torque on long cantilever under the earthquake along the bridge; A formula is given according to a simplified mechanical model to calculate the torque.Secondly, according to the mechanical features of the structural system, the applicability of the seismic codes used in the seismic design is analyzed. The study shows that:(1) Compared with the codes for seismic design of building and highway bridges,Code for Seismic Design of Railway Engineering has some limitations in such aspects as design concept, analysis method etc.;(2) Due to the effect of accidental eccentricity, it cannot adopt single pier mechanics model to calculate the bending moment of end pier of structure;(3) It recommended that engineer should check the torque according to the Guidelines for Seismic Design of Highway Bridges section 5.5;(4) It recommended that relevant departments compose a better targeted seismic code for the structure system, and organize experts to do specific examination of aseismatic design to ensure the seismic safety of the structure.Finally, aimed at the problems of structure in the anti-seismic aspect, the paperproposes plans for improvement, and then verifies the effectiveness of the improved,the study shows that:(1) The structural system of single pillar and long cantilever elevated railway station with escalator at the both ends of the structure can effectively increase the lateral and torsional stiffness,improve the yield mechanism of structure under the high-lever earthquake and enhance the seismic performance of the structure;(2) Reducing stiffness of the longitudinal edge beam of the structure can effectively reduce the torque of long cantilever under the seismic. And a control principle of long cantilever section size and reinforcement is proposed;(3) A measure that changing the collection type between longitudinal edge beam and long cantilever from rigid connection into hinged joint is proposed, which can completely release the bending moment of the long cantilever beam.