Research On The Tension Performance Of Dahurian Larch Joints Connected By Truss Plates

Truss plate is a very important connector in timber construction, which is used widely in light-frame roof and floor trusses, so the determination of truss plate properties is necessary for the application of wood in modern timber construction. Combining the trend of the nationalization of timber construction, use larchwood dimension lumber and imported truss plates to manufacture truss plate connection, and study the tension properties of the connection. By means of strain gauges, the elastic modulus of larchwood dimension lumber is tested, and four standard modes of connections are tested according to GB50005-2003.The results showed that: the design value of ultimate bearing capacity of tooth withdraw and truss plate is determined according to the tests results. The resistance slide capacity is also calculated. The curve of load and displacement is obtained by Foschi equation with Origin7.5 program, and the accuracy and efficiency of this model was validated with practical examples. The performance parameter of connection is obtained by two means-Foschi equation method and tangent method. It is appropriate to use two means-Foschi equation method and tangent method to obtain the performance parameter of connection, because both two results have little error. The conservative calculating method of connection ductility ratio is proposed, and the result is ductility ratio vary with the modes of connection- the modes ofα=0°is obviously higher than the modes ofα=90°. The ductility ratio ofα=0°is greater than 2.0, which is up to par of aseismic structure. Regression analysis showed statistically unsignificant effects of larchwood MOR on parameter values. The effect was not consistent across joint types or parameter values, and the effect showed no observable pattern. A three-dimensional finite-element model of tension-splice joint was developed in Ansys 9.5 with emphasis on modeling the interface between the teeth and wood using contact elements. The finite-element model predicted axial stiffness of the tension-splice joint, and the average of the asolute value of the error in the phase of small deformation (between predicted and experimental results) was less than 5%.