Finite Element Study On Mechanical Behavior Of Splints Connections With Teeth In Glulam Reticulated Shells

With the development of green buildings,modern wood structures are gradually rising.Glulam reticulated shells are widely used in large-span projects at home and abroad.There are many types of connections suitable for glulam reticulated shells,among which bolted connections are more convenient to install and more suitable for the development trend of assembled architecture in China.Because glulam is anisotropic material,glulam around bolt holes is prone to crack under load,and the flexural stiffness of connections is low.In order to improve the mechanical behavior of connections in glulam reticulated shells,steel teeth can be added to the splints to solve the problem of low flexural stiffness of connections.Splints connection with teeth could reduce the rotation of glulam beams and plastic deformation of bolt holes by using mechanical biting between steel teeth and glulam beams.Therefore,the mechanical behavior of the splints connection with teeth is quite different from that of ordinary splints connections.At present,the research on the splints connection with teeth is in the initial stage,so it is necessary to carry out in-depth finite element analysis on the mechanical behavior of the splints connection with teeth.In this paper,finite element software ABAQUS is used for numerical simulation.1)The mechanical behavior of the splints connection with teeth under monotonic and hysteretic loads is studied,the effects of defects and bolt diameters on flexural stiffness of the splints connection with teeth are analyzed,and compared with those of the ordinary splints connection under the same parameters.The influence of steel teeth ratio and splint flange thickness on flexural stiffness of the splints connection with teeth is studied.2)In order to study the mechanical behavior of the splints connection with teeth under the combined action of axial force and bending moment,the eccentric load were applied to the finite element model to study the influence of eccentricity,slenderness ratio and defects on the ultimate bearing capacity of the splints connection with teeth,and compared with those of the ordinary splints connection under the same parameters.The influence of steel teeth ratio and splint flange thickness on ultimate bearing capacity of the splints connection with teeth is studied.The formulas for calculating the ultimate bearing capacity of splints connections with teeth under eccentric load are derived.The results show that:(1)Under the action of bending moment,the ordinary splints connection occurscompression failure of bolt holes in glulam beams and the splints connection with teeth occurs tension failure of splints flange.The splints connection with teeth transmits the load through the steel teeth and the bolts.Compared with the ordinary splints connection,the flexural stiffness and seismic performance of the splints connection with teeth are obviously improved,and the flexural stiffness is less affected by the defects and the bolt diameter.(2)Under eccentric load,the shear failure of the glulam beams in ordinary splints connection and splints connection with teeth occurs when the eccentricity is small.With the increase of eccentricity,the failure mode of ordinary splints connection is changed to that compression failure of bolt holes in glulam beams,while that of the splints connection with teeth is changed to that tension failure of splints flange.With the increase of eccentricity and slenderness ratio,the reduction of ultimate bearing capacity of the splints connection with teeth is less than that of the ordinary splints connection.Compared with the ordinary splints connection,the ultimate bearing capacity of the splints connection with teeth is less affected by the defects.(3)The flexural stiffness and ultimate bearing capacity of the splints connection with teeth increase with the increase of steel teeth ratio and thickness of splint flange.It is suggested that the steel teeth ratio should be 0.65%-0.80%.