| Modern architecture is developing towards the direction of long-span,high-level and assembly.In order to meet the needs of modern construction,the splicing and extension of wood structure is imminent.Therefore,all kinds of wood structure connection forms are constantly proposed and improved,and wood structure connection has been vigorously developed,which has become a hot research field.As one of the most common forms of wood structure connection,glued wood steel plywood bolt connection has developed rapidly with the advantages of high strength,easy processing,convenient splicing and fast assembly.However,in practical engineering application,steel plywood bolted glued wood beams or other glued wood bolted structures are often subjected to dynamic loads such as vehicle and mechanical vibration,which may cause certain looseness between glued wood and steel plywood bolt,and bring risks to the reliability of the connection,thus greatly affecting the steel plywood and bolt glued wood Work together effectively.In order to ensure the reliable connection of glued wood steel plywood bolt connection,and to verify the dynamic performance of the connection under the dynamic load,or the seismic performance under the seismic load,this paper considers the parameter influence of the ratio of glued wood thickness to bolt diameter(thickness diameter ratio),the bolt spacing along the grain,the bolt staggered arrangement,to carry out the hysteresis of glued wood steel plywood bolt connection Performance test.This paper discusses the dynamic performance of glued wood steel plate bolted connections by using the hysteretic test method and the finite element macro model analysis method.(1)According to the structural characteristics of glued wood steel plywood bolt connection,considering the influence of the ratio of glued wood thickness to bolt diameter(thickness diameter ratio),bolt spacing along the grain,bolt staggered arrangement and other parameters,a total of 39 glued wood steel plywood bolt connections in 13 groups of 4 categories were designed and manufactured,and the hysteretic performance test was carried out under the low cycle repeated load.The failure mode and seismic behavior of glued wood steel plate bolted connections under repeated loads are studied.(2)The results show that in the single bolt connection,the failure mode of the joint gradually changes from "bolt rigidity" to "double hinge",while the failure mode of the glued wood gradually changes from the overall bearing failure of the pin groove to the extrusion failure of both ends,and the hysteretic curves of the test pieces basically show full bow and prism.In the multi bolt connection,the main failure modes of bolt and Glulam are "double hinge" failure and compression failure at the end of pin groove.With the increase of bolt parallel space,the bearing failure deformation at both ends of pin groove of Glulam decreases gradually,and the hysteretic curve of the test piece presents full bow shape,the bearing capacity and initial stiffness of the test piece increase gradually,and the pinch effect of the hysteretic curve decreases gradually.When the bolt parallel space increases,the bearing capacity and initial stiffness of the test piece increase gradually,and the pinch effect of the hysteretic curve decreases gradually When the spacing is 200 mm,the increase of ultimate load increases by 10.8%and then tends to be gentle,the increase rate of initial stiffness slows down greatly,and the degradation rate of stiffness is basically the same as that when the bolt is 250 mm,and the design of bolt’s spacing along the line is the best.Compared with bolt parallel arrangement,the stiffness degradation rate of bolt staggered arrangement is faster,the continuity performance of parallel arrangement is better than staggered arrangement,and the seismic performance is better than staggered arrangement.(3)In this paper,ANSYS macro model is used to verify the hysteretic performance of glued wood steel plywood bolt connection.The test results show that the simulated hysteretic curve is highly consistent with the test results,and the change trend of the extracted skeleton curve is basically consistent with the test value.The overall response of the model clearly shows the three stages of bolt deformation:the initial elastic stage and the elastic-plastic stage with gradually degraded stiffness Stage and plastic stage.(4)One dimensional beam element and combin40 spring element are used in the macro model of finite element to simulate the bolted connection.By optimizing combin40 spring element combination,the simulation of multi bolted connection is realized,which can effectively represent the different stages of the cyclic response of multi bolted connection,ingeniously avoid the complex contact problem caused by the large number of connectors,and simplify the modeling method. |
