Research On High Strength Joint Performance Of Post And Beam Of Larch Glulam With Template Metal Connector

Joint Technology of template metal connectorrefers to wooden members are connected together by using stamping or welded template metal connectors bydesigedspecific formandbolt and steel pin. The joint of template metal connector cansupportthe vertical and horizontalload,resistance moment. Through reasonabledesign, theload-carrying capacity, stiffness, ductility and energy dissipation of template metal connector joint canreach a higher level in timber structure, and meetthe requirements of safety and reliabilityof structure.After analyzing and ascertaining the determining method of embedding strength for dahurian larch and the bending yield strength of fastener used in template metal connector joint, three kinds of the template metal connector--U7F10,U3Z12,U3F12--are designed considering the fastener diameter, number, position and other influences.Installing the template metal connector of post and beam to full-scale test obtained yield load and maximum load of the joint and other strength index,and evaluated the initial stiffness?ductilityand energy dissipationof jonit for post and beam connecting by this template metal connector.Analyzing formulas which decide the yield load of post and beam joint using template metal connector,and the design values of post and beam jonitconnecting bytemplate metal connector were checked separately,whichprovides a reliable theoretical basis for the application of template metal connector in modern timber structure.The main results of this research are summarized as follows:1.5% offset method as a method to determine the embedding strength of wood is reasonable,because the effect of diameter of fastener on the embedding strength of wood was taken into account.Embedding strength of dahurian larch has a difference between calculated results of theoretical formulae from NDS and test results based on ASTM(D5764-97a),which ranged from-2.02% to10.44%.2.Bending yield load,bending yieldmoment and bending yieldstrength of bolt and steel pin determining by 5% offset method is greater than the results determining by the tangent method in test which loaded in three point.The average of bending yieldstrength of bolt determined by 5% offset method is bigger thanby the tangent method 6.11 percent.3.Under cyclic loading, the stiffness of three typestemplate metal connector joints in this studyoverall downwardtrend;These three types of template metal connectorjoints have better ductilityand energy dissipation.4.Using the minimum value of yield load and 2/3 loadas allowable load of template metal connector joints,when the post and beam member grade separately are TCT30 and TCT27,and cross section sizes are 120mm×240mm and 120mm×120mm,singlejoint for template metal connectorof U3Z12, U3F12 and U7F10 short-time allowable load are respectively 41.72 k N?39.94 k N and 32.76 k N.5.The jonit strength of three types template metal connector designed in this study which have a plate is far higher than the jonit strength whichtemplate metal connector not have a plate;And the short-time allowable loadof joint for U7F10,U3Z12,U3F12 are higher than the design value calculating based on force analysis and Technical Specification of Glulam Timber Structure of China,it's reveal that the structure of U7F10,U3Z12,U3F12 is reasonable and this type joint of post and beam has higher safety.