MECHANICAL BEHAVIOR OF THREE-DIMENSIONAL NAILING PLATES JOINTS:EXPERIMENT AND NUMERICAL DESIGN

摘要

The aim of this study is to characterize the mechanical behavior of connections timber-to-timber joistnhangers with specific nail fasteners. The methodology proposed by technical design standards is basednon the hypothesis of an elastic and linear joint behavior. However, the local behavior of joint is semi-nrigid characterized by the ductility of wood material in embedment and the non linear behavior of thennail fasteners in bending. Hence, in this study, the combination of a comprehensive experimental setupnand a numerical approach is developed to analyze the evolution of the forces in the joint. Firstly, variousntests are realized on specific nail fasteners, using different glulam species, in accordance with European testnstandards. They concern the withdrawal push-out test, the single plane shear and the yield bending moment.nBesides, the adequacy of the methodology proposed by Eurocode 5 for dowel-type fasteners is discussed.nSecondly, a similar investigation is carried out on a whole timber-to-timber joint, with nailed tridimensionalnmetal plates. Considering the hypothesis of a semi-rigid behavior of the joint, the stiffness of each fastenernis identified in tension and shear slips. Finally, a finite element model is applied and discussed consideringnthe fasteners represented by bi-directional mechanical springs. The stiffness of each spring is considered asnthe slip modulus of each fastener defined by tests. A semi-rigid formulation was adopted and the overallnjoint behavior is apprehended numerically.