Mechanical characteristics of traditional go-dou and stepped dovetail timber connections in Taiwan

Timber joints are one of the major factors that affect the structural behaviour of timber construction. Research on timber joints has attracted more attention recently in Taiwan. Several types of timber joints were investigated during the past two years, however, the go-dou and stepped dovetail connections, which are usually used to connect frames together and provide out-of-plane stiffness to timber frames, have not yet been studied. The purpose of this paper was to investigate the structural behaviour of these types of timber joints. First, 30 full-scale specimens were tested to study the rotational stiffness of the timber joints. Second, prediction models for rotational stiffness and the ultimate moment capacity of these two types of joints were established based upon a statistical approach. Last, stiffness degradation with cyclic loading was discussed. The results of this paper show that stepped dovetail connections have better performance than did go-dou connections in both ultimate moment capacity and stiffness degradation. In addition, for joints with a deep beam, the rotational stiffness of stepped dovetail connections was higher than that of go-dou connections.