Experiments And Analysis Of The Mechanical Behavior Of Beam-column Joints With Glued-in Rods In Timber Structures

The connections of joints are the key areas in design and research of timber structures due to the non-weldable nature of the timber.The ordinary bolted connections have the disadvantage of low initial stiffness and high amount of steel used.The advances of timber engineering in the field of tall buildings raised a need for high performance of capacity and stiffness of connections.Glued-in rods joints of Glued Laminated Timber is a new technology for timber structures.By putting steel rods into the timber members with environmental-friendly adhesive,the joints can provide a favorable bearing capacity and stiffness.The joints also have a strength of aesthestics and performance of fire proof.In this paper,by using Q235 threaded bolt,18 glued-in joints with 3 kinds of diameters of rods have been designed and manufactured by the method of being glued from the side hole.The effectiveness of this method has been proven.12 of the joints were tested under monotonic load to obtain their moment-rotation curves and analysis the mechanical behavior from 3 levels of heights of loading points.Quasi-static cyclic tests were conducted on the remaining 6 joints,Hysteretic curves and skeleton curves of the joints were obtained.The paper studied the bearing capacity and phenomena of the joints under several conditions,also the hysteretic behavior,energy disspation and ductility characteristics.A finite element model of the joints was developed by using the ABAQUS software,the result of finite element analyzing had compared with the experiments.Parameters analysis have been conducted on the impact on the bearing capacity and the rotation stiffness of the joints from the heights of loading points,yield strength of the rods and anchorage length of the glued-in rods.Some representive formula of guled-in rod have been caculated and compared to determine the anchorage length of ductile failure.The caculated bearing capacity of the joints based on the moment equilibrium and the inequality of the stiffness between tensioned and pressed glued-in rods;A simpler calculation model was derived from assumption of a fixed rotation center of the joints;Considering the effect of combined load on the mechanical behavior of the joints by using the method of yield criterion and Eurocode 5 to evaluate the influence on the moment bearing capacity by shear force.Also using the GB 50005-2017 to caculate the bearing capacity of the joints due to the similarity of bearing capacity characteristics to the nail connection.The research has also based on the same assumption of a fixed rotation center to calculate the rotation stiffness of the joints.This study provides reference for design and engineering applications of the beam-colum joints with glued-in rods.