| In the era of pursuing human settlement environment,environmental-friendly,recyclable and ecological of timber structures has received increasing attention.The large-span timber structure has expands the application of timber structure in the field of modern timber structure with its aesthetic appearance,unique wood atmosphere and technical excellence,it is highly valued for the quickly development and become an important member in the current timber structure field.The reticulated timber shell joint as the hub of structural force transmission,while bearing the connection,it also plays a crucial role in the structural bearing capacity and overall stability.The existing research on the reticulated timber shell joint has many problems such as bulky connection mechanism and excessive rigidity.However,most of the wood components in the actual reticulated shell are less stressed and mainly affected by the axial compression.For the traditional joint,it’s not easy to avoid the waste of rigidity,in addition,the overall aesthetics has also been affected.Therefore,the design method and mechanical performance need to be further studied,which of the new large-span prefabricated joints in reticulated timber shell with relatively small internal forces.This research has theoretical significance and application value for the design and construction of modern long-span wooden structures.In this thesis,a new prefabricated dowel-type connecting mechanism in reticulated timber shell is proposed.According to the design parameters of the reticulated glulam shell in existing research and the specifications to design the wood components and the forms of the metal connector,and determine the rationality of the connection mechanism by the numerical simulation method;then the axial mechanical performance of the connection is studied by a test method.The main work and conclusions are as follows:(1)The material properties test of Douglas fir glulam and steel was completed.The glulam characteristic parameters of the glulam include moisture content、density,、longitudinal compressive strength、longitudinal tensile strength、longitudinal shear strength 、 flexural strength 、 tangential compressive strength 、 radial compressive strength、longitudinal compressive elastic modulus.The tangential and radial elastic modulus of wood is obtained by the stress-strain curve.(2)The proposed reticulated timber shell joint is suitable for large-span reticulated timber shell with axial force as the main internal force,which can be used in non-dome joints,and the force transferred explicitly and effectively.The preliminary check results with finite element analysis show that the designed joint have well overall mechanical performance and can meet the bearing capacity requirements.(3)In this thesis,the axial mechanical performance test was completed for the analysis of failure mode and load-displacement curves and discussing the influence of the steel plate thickness on the bearing capacity.The results show that the new prefabricated dowel-type connections in reticulated timber shell have well bearing capacity,and even after cracking on the wood components,they can still bear the load;the steel connector in the joints mainly bear the connection and force transmission.The steel plate thickness has little influence on the mechanical performance of the joint,and the joint with small deviations in processing and installation with smaller plate thickness,during the loading process,has more stable mechanical performance,the better bearing capacity,and the smaller failure degree of the joint.(4)The continuous wood components are constrained by the steel connector and the discontinuous wood components,lateral displacement occurs with the steel connector as the axis and the additional bending moment is produced due to the vertical displacement that caused by the local buckling of the steel connector,so that the free length parts of the continuous wood components has longitudinal splitting failure by the torque. |
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