The Experimental Study On Mechanical Properties And Reinforcement Of Joint With Sparrow Tenon In Ancient Building Wood Structure

China’s ancient architecture,dominated by wooden structures,is an important witness to history and civilization,and it is unique in the world architecture system.The ancient architecture has a long history and a complex structure.After centuries of years,it has survived and proved its excellent seismic performance.However,many existing ancient structures with wooden structures have caused structural damage of various degrees due to natural disasters and years of erosion,and even face the danger of collapse.The connection between large wooden structures of ancient buildings in China is mainly based on concrete connections,and then auxiliary mechanical components such as querque are used to make the nodes have better anti-seismic energy consumption effects.This article follows the principle of "old and old,as the old"maintenance and reinforcement of ancient architecture,applying modern techniques to study the mechanical properties and the damping mechanism of wooden structures and joints,mastering their laws,and finding a scientific and environmentally friendly reinforcement method.Through the low-cycle reciprocating load tests on the four timber frame models with nodes,the hysteresis curves and skeleton curves between the failure modes,bending moments,and corners,the stiffness degradation of the joints,and ductility were obtained.Coefficients,and fitting out the equations that reflect the general law of bending moment angle relationship.The tests showed that the main failure mode of the concrete transmission node was the damage of the pullout,and the bending damage occurs at the root of the concrete.The wood grain at the root of the concrete was torn by the wood fiber of the tensile surface,and the plastic deformation of the concrete head and the cornice occurs;The back curve shapes were all anti-Z-shaped,with a clear pinch effect.The stiffness and energy dissipation performance of the joints gradually decrease as the plastic deformation increases and the pull-out slip increases.The ABAQUS software was used to simulate the finite element simulation of the joints of the test hull.The finite element model deformation map,the stress distribution cloud diagram,the skeleton curve between the bending moment and the stiffness degradation curve were obtained.Comparing the test results with the finite element analysis results,the feasibility of the simulation model and the accuracy of the pseudo static test results are verified.Based on the analysis of the mechanical tests and simulations of the joints,four wood frames with damaged queer concrete were reinforced with carbon fiber cloth.The pseudo-static test is used to obtain the relationship between the hysteresis curve of the bending moment,the skeleton curve of the bending moment,the stiffness degradation curve,the ductility coefficient,and the bending moment angle after reinforcement.Through comparative analysis of the test results before and after reinforcement,it is concluded that the carbon fiber cloth has a good reinforcement effect on the joints.