| In recent years,prefabricated steel buildings have become one of the most popular structural forms and have been widely used in engineering around the world.It is worth noting that the stress mechanism of the beam-column connections formed by different connection methods is also very different.The stress mode of the beam-column connections can affect the seismic performance of the whole structure.In the Hyogoken-Nanbu earthquake in 1995,it was the first time that the beam end fracture events were confirmed at the beam-column connection of steel frame structure in Japan.Steel buildings suffered significant damage,even collapses,which broke the traditional impression that steel frame structures have excellent seismic performance.Therefore,experts and scholars have been devoted to the research of steel beam-column connections with excellent seismic performance.The reasonable design of beam-column connections is of great significance to ensure the overall stability of the structures in earthquakes.The beam-column connections with a different connecting method in the splicing area were investigated in this paper.Besides,this paper mainly studied the influence of different bolt holes on the seismic performance of the connections.To be specific,the cantilever beams and frame beams by butt welding,while the lower flange adopts bolt connection between cantilever beams and frame beams.Firstly,by changing the length,width,thickness of the lower flange splice plates,and the number of bolt holes,four groups of beam-column connections with circular bolt holes were obtained.Subsequently,the finite element model of the connections was established,and the hysteretic curves of the frame beam end,the hysteretic curves of the splicing area,the skeleton curves,and the proportion of energy dissipation in the splicing area were obtained by processing the simulation data,to study the seismic performance of the connections.Secondly,based on the principle of slip energy dissipation,the bolt hole forms were changed from the circular holes to the slotted holes.To investigate the energy dissipation performance of the beam-column connections with the slotted holes in the web plates and splice plates,eight groups of specimens were designed.By changing the size of the slotted holes and the arrangement in the web plates,the finite element modeling was also carried out to analyze the specimens’ energy dissipation performance.The research contents are divided into the following two parts:(1)To investigate the seismic performance of the beam-column connection with a different connecting method in the splicing area,four groups of specimens were designed.These specimens adopted the circular holes in the web plates and the lower flange plates.The specimens’ main testing parameters are the length and width of the lower flange splice plates,the thickness of the lower flange splice plates,and the number of bolts.In addition,all specimens were designed to apply low cycle loading by ABAQUS.Due to the use of different connection methods of the beam-column connections between the upper and lower flange of the splicing area,all specimens showed high energy dissipation ability and good seismic performance.The deformation of the splicing area is the main factor of the energy dissipation of the specimen,including the extrusion deformation of the bolt and the buckling deformation of the splicing plates.The cross-sectional area of the splicing plate mainly affects the ultimate bending capacity of the beam-column connections.Reducing the cross-section area will slightly reduce the ultimate bending capacity.In addition,the change of the thickness of the lower flange plate is more significant than the width for the influence of resisting bending capacity.(2)Based on the principle of slip energy dissipation,the bolt holes of web plates and lower flange splice plates were changed from circular holes to slotted holes.In order to study the influence of the arrangement and size of slotted holes on the energy dissipation performance of the beam-column connections with welded upper flange and bolted lower flange,eight groups of specimens were designed.Specifically,the specimens’ main testing parameters are the size of slotted holes and the arrangement of slotted holes in the web plate.Similarly,all specimens were applied low cycle loading by ABAQUS.Subsequently,the influence of slotted holes’ size and the arrangement of slotted holes in the web plate on the energy dissipation performance was analyzed further to evaluate the beam-column connections’ seismic performance.Compared with the hysteretic curves of the beam-column connections with slotted holes and that with conventional circular holes,it can be seen that the rotation ability of the connections with slotted holes is better than that of the connections with circular holes.Besides,the hysteretic curves of the connection with slotted holes show obvious slip energy dissipation characteristics.The connection can dissipate energy effectively through slip.At the same time,the appearance of the slip segment significantly improves the ductility of the connection,indicating that the connection has high energy dissipation performance.Compared with the specimens with circular holes in the lower flange plates,the splicing area’s energy consumption ratio with slotted holes in the lower flange plates is significantly increased.This phenomenon further proves that the energy dissipation of the connection with slotted holes can be achieved through the slip of the splicing area,the deformation of the splicing plates,and the extrusion between the bolt shanks and the hole walls. |
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