The Mechanical Performance Of A New Type Assembled Connection Joint In Large-scale Timber Reticulated Shell

With the rapid development of the modern economy,buildings based on the people's living standards have become more and more prominent in green ecological characteristics,and wooden structures have gradually entered into the human vision.With the development of timber manufacturing and processing technology,the structural form of modern wood-framed buildings is no longer limited to traditional structural forms,and has begun to develop in the direction of large-span public buildings and high-rise buildings.In recent years,large-span wooden structures have been widely used in the field of public buildings.Among them,the single-layer reticulated shell structures with relatively light weight and convenient for construction are one of the most representative structural forms in the large-span system of timber structure.As for the most common connection form of reticulated timber shell,joint that uses steel column combined with slotted-in steel or slotted-out steel usually has a strong stiffness and a large weight,which is uneconomical and unfavorable for installation.In addition,due to the excessive exposure of the steel,it affects esthetic feeling and weakens the unique natural atmosphere of wood.Therefore,the research group proposed a new prefabricated type connection in reticulated timber shells,and found problems such as installation deviation in the test.In this thesis,by analyzing the axial compression performance test results and failure phenomena of the new prefabricated type connection in reticulated timber shells,an improved design scheme is proposed,and the bearing capacity is checked by numerical simulation method,then analyzing mechanical properties of the joint through axial compression performance test and bending performance test.The experimental study on the mechanical performance of the joint to clarify the rationality of the improved joint is of practical value for the development of large-span wooden structures in China.The main work and conclusions of this study are as follows:(1)The test results of the improved joint are analyzed,and the improvement measures are proposed whitout reducing the bearing capacity of the joint.The finite element analysis software ABAQUS is used to analyze the improved bearing capacity and the path of the force transmission.The results show that the joint performance is promoted than before.(2)The axial compression test of the improved joints is compared with previous results.From the comparison of the phenomenon and the joint load-displacement curve,the improved joint has good mechanical performance and axial bearing capacity.There are no seriously split and damage of each member.Although the installation error still exists,the problem of additional torque which is generated in experiment has been avoided(3)The bending performance test of the joints is carried out.From the bearing capacity and deformation characteristics,the bending resistance of the joint is better.Since the axial force and bending moment of the reticulated shell member exist,the vertical displacement of the joint is larger without considering the axial force.So the failure of the discontinuous member in the test can be avoided by the axial pressure.(4)It can be seen from the different failure phenomena of each discontinuous member,the installation deviation and the quality of machining timber are important factors affecting the performance of the joint.Therefore,in-depth study on the allowable installation deviation should be carried out in the future.