Research On The Influence Of The Vertical Connection On The Seismic Performance Of Modular Stacked Steel Structures

Modular buildings has the advantage of green,low-carbon,environmental protection,rapid fieid installation,high precision and quality.However,the connection of modular stacked steel structure is the key and weak point in its seismic resistance,well the research is still rare.This paper is to explore the influence of vertical connection on the seismic performance of modular stacked steel structure.The main research work and results are as follows:?1?Modular stacked steel structures with two kinds of vertical connection modes:hinged and rigid were modeled and analysis were conducted,including stiffness,modal and response spectrum analysis of two vertical connection methods:hinged and rigid-connected modular stacked steel structure to find out that under the action of earthquake,modular stacked steel structure due to the existence of the vertical connecting layer,the column shear force,layer stiffness and interlayer displacement are different from the traditional structure.The results show that:The connection gap made the modular stacked steel structure become a vertical irregular structure and change the mode of vertical shear distribution;the dramatic increase of the shear force of the connection gap and the bending-dominated-deformation led to two different failure modes:shear strength failure of the connection gap and bending deformation failure of module box.The results showed that,the shear failure could occur prior to the bending failure under certain conditions.?2?The pushover analysis method was used to further analyze the two types of structures.First,the proper loading methods were studied by comparing the shear forces from the 1st mode method and the response spectrum analysis;then,the structure was assigned shear plastic hinges and bending plastic hinges,respectively,to study the failure thresholds,the characteristics of forces and deformations,and failure mechanisms of the two types of restraints;the difference of rigid and hinged connection was also studied;The results show that:The difference of displacement responses caused by the two loading modes was not obvious,which indicated that,the shear distribution had little influence on the displacement;deformation was mainly bending deformation,and so could not reflect the shear force of the connection gap;while the 1^st mode method calculates the loading force using the deformation,and underestimated the shear force of the connecting layer,so it was not suitable for the modular stacked steel structure.Whethe the connection is rigid or hinged had little influence on the overall seismic performance of the structure,because the two trends were the same,while the values were slightly different.Especially when only shear plastic hinges existed,the responses of rigid joint and hinged joint were exactly the same.?3?Change the size of the connection gap and the stiffness of the connection and perform the parameter analysis of the vertical connection,to further study the sensitivity of the seismic performance of the modular stacked steel structure to the vertical connection,and conduct a deep pushover analysis of the typical structure;The results show that:The story shear force and column shear force of the vertical connection layer decreased with the increase of the vertical connection gap,and increased with the increase of the connection stiffness.However,small gaps and large rigidities of the connection helped to improve the bearing capacity of the connection.?4?Nonlinear dynamic time history analysis method was performed to analyze the seismic performance of the above typical structure,and the results were compared,verified,and compentated with the pushover analysis results.The results show that:The results of nonlinear dynamic time history analysis were consistent with those of the pushover analysis.