Feasibility of Timber Pegged Joints for Seismic Design of Structures

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.