Research Of Seismic Response And Vibration Reduction Of Space Structures Considering Soil-Structure Interaction

The space structures have been widely applied in important buildings such as airport terminal buildings and gymnasiums.In structural design,the rigid foundation assumption is usually adopted that soil-structure interaction effects are ignored.However,the post-earthquake investigation of the Lushan earthquake in 2013 found that the spatial grid structure,which was generally believed with better seismic performance may also be destroyed by earthquake due to the soft soil-structure interaction effects.Therefore,it is of great significance to analyze the seismic response of spatial grid structure considering the soil-structure interaction.In this paper,the space structures are the research object in this paper,through the viscoelastic artificial boundary to consider the relationship between soil-structure interaction.Firstly,the equivalent node force calculation formula of three-directional ground motions based on three-dimensional viscous-elastic artificial boundary was deduced in this paper.And then based on MATLAB software,the program for calculating equivalent node force that ABAQUS can read directly was given and its effectiveness was verified by an example.The seismic response analysis of square pyramid space grids and single-layer reticulated shell which take into consideration of soil-structure interaction were carried out.Finally,the influence of the equivalent stiffness coefficient and the equivalent damping coefficient on vibration control of viscoelastic structure considering the soil-structure interaction was analyzed.The main conclusions of this paper are:(1)The results showed that each of natural frequencies considering soil-structure interaction is longer with shear wave velocity of soil declined,but there is no obvious change of every mode shape.(2)The soil-structure interaction system for square pyramid space grids that built on the typical soft soil ground under earthquake loading is analyzed.The maximum axial force of members is 2.98~8.70 times that under the assumption of rigid foundation.So that the middle of lower chord and upper chord step into plastic stage in advance and the internal force of around members will be redistributed.(3)The peak acceleration of each node considering soil-structure interaction is bigger than the case of rigid foundation assumption that built on the soft ground.And the node of acceleration amplification coefficient decreases as the peak accelerations increases.In the meantime,the vertical relative displacement of nodes considering soil-structure interaction is 2.20~5.38 times that the case of rigid foundation assumption.(4)The soil-structure interaction system for single-layer reticulated shell that built on the typical soft ground under earthquake loading is analyzed.Reactions at support of single-layer reticulated shell will be 1.03~1.54 times that the case of rigid foundation assumption.Node of horizontal displacement will be 2.00~3.00 times that the case of rigid foundation assumption.But this value becomes 0.16~0.93 times of vertical displacement.Node of horizontal acceleration can be 1.26~1.67 times comparing with rigid foundation assumption.(5)Viscoelastically damped structure can effectively reduce the response of horizontal displacement and acceleration.By selecting the equivalent stiffness coefficient and the equivalent damping coefficient appropriately,it will be a better decreasing amplitude ratio.