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This paper investigates the feasibility of employing timber pegged joints in modern seismic-resistant structures or for retrofitting existing structures. The behavior of timber pegged connections has been investigated for about twenty years, but seismic design aspects are not treated in existing standards. In the framework of the force-based design approach, this paper analyzes and defines seismic design aspects and rules for timber pegged connections that are easy-to-use in engineering practice. A large database (more than 350 test results) has been elaborated and the data processed with the purpose of (1) analyzing the effectiveness of the European Yield Model for evaluating the maximum strength of the connection, accounting for the particular embedding behavior due to the presence of timber peg; (2) assessing and defining the capacity design rules to design the dissipative regions (i.e., overstrength factor); and (3) defining the available ductility of the connection with identification of ductility class intervals. The obtained results proved that timber pegged joints have a good potential to be used in seismic-resistant structures. In fact, data processing identified a suitable value for the overstrength factor (useful to project the joint with the capacity design) similar to that used for steel-dowelled connections, and defined a likelihood range of ductility classes. Finally, it is highlighted that the European Yield Model can be a practical tool to calculate connection strength, provided that some modifications are included to consider peg behavior.

The effectiveness of an all-timber solution, based on the uses of timber pegs, to reinforce stop-splayed scarf joints with transverse key has been investigated in this paper. An experimental program on unreinforced and timber pegged reinforced scarf joints subjected to tensile loadings has been carried out. Two timber pegs made with ash, and having a diameter equal to 20 mm, have been used as fasteners to reinforce the scarf joints. The experimental outcomes have been analysed and critically discussed, focusing on the role of timber pegs in reinforcing scarf joints. Three fundamental aspects have been investigated: load-bearing capacity, ductility and influence of slenderness ratio (between thickness of members and diameter of the peg) due to the introduction of timber pegs. Test results showed that timber pegs provide adequate robustness to the connections because they modified both force-displacement constitutive behavior (increasing load-bearing capacity, stiffness and ductility) and failure mechanisms from brittle to ductile. It has been also proved that greatest slenderness ratios are effective in enhancing the ductility of the connections; thus, at the same thickness of members, pegs with reduced diameters could be preferred in reinforcing scarf joints. From testing, important findings on the qualitative behavior of scarf joints reinforced by timber pegs are emerged, but the reduced number of specimens did not allow conclusive considerations and future investigations will be necessary to support the obtained results.

In this paper the results of a finite element analysis on connections with timber pegs are presented. The main aim of numerical investigation was to assess the reliability of implemented model based on Hashin criterion for material constitutive law in predicting the behaviour of selected connections. The material model was calibrated against the results of experimental tests on prismatic and peg specimens. On the basis of obtained parameters, a numerical model of connections was implemented taking into account contact interactions between the pegs and the plates. Finally, to validate the developed finite element model a comparison of experimental and numerical results is presented.