Experimental Research On Flexural Load Bearing Capacity Of Cross-Grain Reinforced Glued Laminated Wood Column-Steel Beam Node

In recent years,China has been vigorously promoting green energy-saving buildings,and promoting the application of wood structure and mixed wood structure buildings has become an important part of ecological urban construction.Therefore,it becomes more important to conduct relevant experimental research on wood-steel hybrid structures.In this thesis,a glued wood column-profile steel beam hybrid frame structure is proposed,which gives better play to the advantages of both materials.Wood has high compressive strength and large compressive plastic deformation capacity,which is suitable for columns mainly under pressure;steel has high strength,high stiffness and convenient node connection,H-beam has greater bending capacity than glued wood beam,and the node has much greater bending capacity than steel infill plate bolt connection node.The glued timber column-steel section hybrid frame structure can be applied to large span structure,and the lateral stiffness is large,which has greater application value in actual engineering,and it is necessary to carry out research on glued timber column-steel beam hybrid structure.The nodal connection of the beam-column-frame structure is extremely important,which is the key to ensuring the load transfer and overall strength of the structure.The cross-grain bearing capacity of wood is low,and the nodes of wood columns and steel beams are prone to local cross-grain compression damage and structural safety,so this paper will enhance the cross-grain reinforcement of glued wood columns to improve the nodal local compression bearing capacity and nodal bending bearing capacity.This thesis adopts the research methods of experimental research,theoretical analysis and finite element simulation analysis to study the force performance of cross-grain reinforced glued laminated wood column-steel beam nodes,and the main research contents and results are as follows:(1)The local compression test of 16 specimens of glued laminated wood column was completed,and the strength and deformation and other stress characteristics of the footprint glued laminated wood column with cross-grain local uniform compression and cross-grain reinforced local uniform compression were investigated,respectively.The research shows that the local compression deformation of the cross grain of the footprint glued laminated wood column shows a more obvious elastic stage and plastic stage;the bearing capacity of the cross grain of the footprint glued laminated wood is basically the same in the tangential and radial directions,indicating that the mechanical properties of the cross grain in the tangential and radial directions can be approximately isotropic;the cross grain reinforcement has a significant effect on improving the local compression bearing capacity and stiffness of the cross grain.(2)Eleven nodes of glued laminated wood column-steel beam were tested for bending load capacity,and the nodes were monotonically loaded with the cross-grain reinforcement of the full-scale glued laminated wood column and the flexible and rigid end plates of the steel beam,respectively,to study the moment-torsion angle relationship of the nodes and other stress properties.The study shows that the load-bearing capacity and stiffness of the nodes after cross-grain reinforcement of the glued laminated wood are greatly improved,and the improvement is positively related to the diameter and amount of reinforcement,and the influence of the amount of reinforcement is greater than that of the diameter of reinforcement;the initial rotational stiffness of the nodes of the glued laminated wood column-steel beam without cross-grain reinforcement can reach 1895kN·m·rad-1,and the rotational stiffness of the nodes after reinforcement is improved by 75%;the deformation performance of the nodes of the glued laminated wood column-steel beam without cross-grain reinforcement is good.The deformation performance of the glued laminated wood column-steel beam node is good,and the damage modes without and with reinforcement are both ductile damage.(3)Based on the experimental study,the calculation method of the flexural bearing capacity of the glued wood column beam node was proposed,and the theoretically calculated value of the flexural bearing capacity of the node is in good agreement with the measured value.(4)ABAQUS finite element software was used to simulate the bearing capacity of the glued wood column-steel beam node under monotonic loading,and the influence of parameters such as reinforcement diameter and reinforcement quantity on the node bearing capacity was investigated.The finite element simulation results are close to the experimental results.The parametric analysis shows that increasing the reinforcement diameter has little effect on the mechanical properties of the node,and the initial stiffness,yield moment and bending capacity of the node are mainly controlled by the reinforcement quantity,and it is suggested that the reinforcement diameter should not be less than 10 mm.