Mechanical performance of dovetail joint related to the global stiffness of timber roof structures

Abstract

This paper focuses on analyzing mechanical behavior of dovetail joints with certain geometries and manufacturing imperfections subjected to different loadings. Parameters such as tension stiffness, strength and rotational stiffness are verified using experimental tests. It was found that steeper angle between mortise-tenon contact areas provides significantly higher stiffness of the joint. Another part of the paper focuses on examining influence of manufacturing precision on mechanical performance of dovetail joints. It is found that small gaps up to 2 mm between mortise-tenon contact areas have negligible impact on dovetail performance while gaps of 5 mm may slightly influence joint’s performance by reducing joint’s tensional stiffness by 30 % and strength by 13 %. Furthermore, numerical models of full scale timber frames are constructed and dovetail joints in these models are assigned parameters resulting from experimental testing. Influence of dovetail’s tensional and rotational stiffness on global behavior of timber trusses is examined and it is concluded that rigid hinges carrying no moment can be used for modeling dovetail joints in full scale timber frames. Finally, it is concluded that precise analysis of dovetail’s parameters does not have to be performed when examining global quasistatic behavior of timber structures as these parameters have low impact on structural behavior of the whole construction. Tensional stiffness of dovetail can be used for estimating maximum allowable displacement of tenon for on-site health monitoring of historical dovetail connections.