| The transportation hub undertakes the functions of personnel flow and goods movement.The most important feature of a modern urban comprehensive transportation hub is transportation integration,which realizes multiple line connections within the transportation hub building.The use of multiple building functions determines the complex structure and large volume of the hub.Because the hub structure requires a large space,a large-span space structure is used as the roof,and the lower main structure needs to use a multi-layer concrete structure due to complex architectural functions,sometimes with an underground structure.The lower main structure of the large-span space hub structure needs to bear the train load,which makes the lower main structure rigid,resulting in an increase in the rigidity ratio of the structure to the foundation,and the interaction between the soil and the structure changes the dynamic characteristics and seismic performance of the structure,so the influence of soil-structure interaction should be considered when studying the seismic performance of hub structures.This thesis selects two typical large-span spatial hub structures to study their seismic performance under consideration of soil-structure interaction.The main research content and results of this thesis are as follows:(1)According to the structure type of the roof,select two typical large-span spatial hub structures,and establish their rigid foundation hypothetical model and a soilstructure interaction model.By simulating the hysteresis test of reinforced concrete columns,verify the applicability of the adopted concrete and steel constitutive model.By comparing the calculation results of the three-dimensional free-field soil finite element model established in this thesis with the ones of the one-dimensional soil analysis program EERA,verify the applicability and correctness of the soil modeling method.(2)Analyze the natural vibration characteristics and the time-history response of the large-span spatial hub structure assumed by the rigid foundation and the one considering the soil-structure interaction under the action of three-dimensional earthquake.Summarize the influence of soil-structure interaction on the seismic response of large-span spatial hinge structures.The results show that: considering the soil-structure interaction,the dynamic characteristics of the hub structure are changed,the natural frequency of the hub structure is reduced,the tubular truss hub structure is reduced by 11.4%,and the double-layer reticulated shell hub structure is reduced by26.4%;The deformation of the roof and lower concrete structures increases,and the deformation of the roof structure increases by about 13.4%～31.6%,and the deformation of the lower concrete structure increases by about 14.7%～35.5%;the stress of key members of the large-span roof structure decreases by about 2.5%～32.5 %,the stress of a few low-stress bars increases.(3)Considering the soil-structure interaction,the response of the large-span spatial hub structure under strong earthquakes is analyzed,and the plastic development law and weak points of the large-span spatial hub structure are summarized.The results show that the plastic area of the roof of the tubular truss hub structure is mainly concentrated in the column bearing area and the mid-span area under the action of Severe earthquakes.The displacement of the joints in the roof,the number of yielding members,and the maximum plastic strain of members increase steadily with the increase of the acceleration amplitude of the bedrock wave.For the reticulated shell hub structure,under the action of Severe earthquakes,the members near the supports and in middle of the roof yielded,and developed to the members near the supports on both sides of the roof to the range of 1/4 span and in the full span of the middle of the roof yielded.With the increase of the acceleration amplitude of the bedrock wave,the displacement of the joints in the roof,the number of yielding members,and the maximum plastic strain of the members increase steadily. |
