| The multiple use functions of the comprehensive transportation hub determine its complex structure.The roof usually adopts a spatial steel structure,and the lower main structure generally adopts a multi-layer reinforced concrete frame structure.This paper takes a typical large-span space hub as the research object,analyzes its seismic response characteristics,and applies the horizontal-vertical layered isolation technology proposed by the research group to the hub structure,that is,the lower frame structure of the hub is set with horizontal isolation,and the roof is isolated.Vertical isolation is installed at the support of the cover structure,and the shock absorption effect of the layered isolation hub structure and its pipeline system is analyzed.The main research contents and conclusions are as follows:(1)Research on the seismic response characteristics of typical large-span space hub structures.The finite element model of the overall structure of the hub and the roof structure are established,and the seismic response and the acceleration response of the hub structure are analyzed respectively.The results show that the substructure has an amplifying effect on the seismic response of the roof.Under the action of a rare earthquake of 7 degrees,the peak relative displacement of the roof nodes increases by32.5%～422.1%,and the peak stress of the key members increases by 25.0%～91.8%;The vertical acceleration amplification effect of the structure is weaker than that in the horizontal direction,and the vertical acceleration response of the roof nodes increases suddenly,indicating that the roof is a vertical earthquake-sensitive structure.(2)Analysis of the shock absorption effect of the main structure of the horizontalvertical layered seismic isolation hub.The base horizontal isolation,threedimensional isolation and horizontal-vertical layered isolation pivot structure finite element models of the lower frame structure were established respectively,and their shock absorption effects were compared and analyzed.The results show that under the action of a rare earthquake of 7 degrees,the layered isolation can improve the vertical acceleration damping rate of the roof structure by 27% compared with the horizontal isolation;the layered isolation is more conducive to reducing the roof truss than the three-dimensional isolation.The lower chord stress and the horizontal isolation are beneficial to reduce the web stress;the rocking response of the threedimensional isolation device causes the interstory displacement of the structure above the isolation layer to be larger than that of the layer isolation;the shock absorption effect increases with the earthquake intensity The increase indicates that the horizontal-vertical layered isolation system is suitable for large-span space hubs built in high-intensity areas.(3)Optimization of the horizontal isolation position of the horizontal-vertical layered isolation pivot structure.The seismic response of the structure when the horizontal seismic isolation layer is set at the base of the lower frame structure of the hub or at different positions between layers is compared and analyzed.When the column bottom of the waiting hall is used,the shock absorption effect is reduced.When the track design allows,it is recommended to set the horizontal shock isolation at the column bottom of the track layer.(4)Analysis of the shock absorption effect of the pipeline system of the horizontalvertical layered seismic isolation pivot structure.The seismic response and shock absorption effect of horizontal isolation,three-dimensional isolation and horizontalvertical layered seismic isolation hub pipeline system are compared and analyzed.Seismic isolation is increased by 15.4% and 15.6% respectively.Compared with three-dimensional isolation,the layered seismic isolation can increase the vertical displacement damping rate of the pipeline by 13.5%,effectively reducing the risk of earthquake damage to the pipeline system due to excessive relative displacement. |
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