Study On Seismic Behavior Of Wood Truss K-Joint Anchorage Connection

In recent years,with the increasing awareness of green development,wood structure buildings have attracted wide attention.As a crucial part of wood structure buildings,the research on wood structure connection nodes has also progressed rapidly.However,at present,there are still many deficiencies in the integrity of wood structure connection nodes,and its innovation and practicability need to be further improved.Therefore,a new type of steel-wood composite anchorage joint is innovatively proposed in this paper,and this joint form is used in the connection of wood truss.Its seismic performance was investigated by combining lowcycle reciprocating test and finite element simulation,so as to provide reference for the improvement and strengthening of the performance of wood structural joints in the future.The main research contents and conclusions of this paper are as follows.(1)The physical and mechanical properties of the wood used in the test were tested.The density,moisture content,radial and chordal compressive strength of the saffron grain,elastic modulus of the striar,and elastic modulus of the radial chord direction of the striking were measured by the material property test of clear wood.Through the experimental study of compressive,tensile,bending and shear strength of wood under different compression ratios,it was found that in the compression ratio range of 0～35%,with the increase of compression ratio,the strength of wood also increases.(2)The pseudo-static tests were carried out on 6 different wood truss K-shaped anchorage joint specimens,and the failure modes of each specimen were obtained.The hysteretic characteristics,ductility,stiffness and strength degradation,energy dissipation capacity and node slip of each specimen were studied and compared.The results show that the failure mode of the joint is mainly manifested as the pulling out failure of wood in the joint area.Compared with other forms of joint joints of timber structure,anchorage joints have better bearing capacity;The ductility coefficient of the joints ranges from 1.36 to 5.19,and the anchorage length has a significant effect on the ductility of the joints;The equivalent viscous damping coefficients of the nodes range from 0.09 to 0.42,and the energy dissipation capacity of the nodes in the late loading period is greatly improved compared with that in the early loading period;The joint has good stiffness and bearing capacity stability.The seismic performance of6 groups of joints is compared and analyzed.The results show that the specimens with wood compression ratio of 40% and anchorage length of 200 mm in the joint area have better seismic performance.(3)ABAQUS finite element software is used to simulate and analyze K-shaped anchorage joints of wood truss,The simulation results were compared with the test results,The error between the two is small,which verifies the rationality of the finite element model.On this basis,the influences of anchorage length,wood compression ratio and steel tube thickness on the mechanical properties of joints are studied.The results show that,within a certain range,with the increase of anchorage length,the bearing capacity of joints also increases to a certain extent,while the ductility of joints increases first and then decreases.When the compression ratio is between 33% and 40%,the radial pressure performance of wood under the transverse bi-directional constraint is not significantly improved.Therefore,the change of wood compression ratio in the joint area has no significant effect on the bearing capacity and ductility of the joint.In the range of 4 ～ 8mm,the influence of steel tube thickness on the bearing capacity and ductility of joints is not obvious.