Stiffness of bolted timber connection

The stiffness equation for connections using fasteners in Eurocode 5 is specified as a function of wood density and fastener diameter only. In this research, an analysis of available data sets on various configurations of tested bolted timber connections has been undertaken in order to predict the initial stiffness of each connection. From the analysis, it is indicated that the stiffness equation specified in Eurocode 5 for bolted timber connections does not adequately predict the initial stiffness. There is a need to incorporate other connection parameters such as geometry into the equation to improve accuracy. Furthermore, in this research, numerical models have been developed to study the stiffness of bolted timber connections loaded parallel-to-grain. From these models, numerical predictions of the stiffness values have been made for various densities, diameters, end distances, row and bolt spacings and thicknesses of the timber members. An analysis of the results has shown that the stiffness of bolted timber connections is strongly dependent on the wood density, fastener diameter, bolt spacing, end distance and thickness of timber member where the greater the density, diameter, bolt spacing, end distance and thickness of timber member, the higher the stiffness value of the bolted timber connection. A relationship for the determination of bolted connection stiffness as a function of the steel - wood - steel connection configuration is presented. The results obtained in the experimental tests are compared with those obtained from the design models. Based on that analysis the accuracy of the predictions is discussed.