Seismic behavior and retrofitting of joints in traditional timber roof structures

The seismic quality of traditional timber structures, as those supporting roofs in old buildings, mostly depends on the condition of their connections. A research program has investigated the behavior of old timber joints and examined retrofitting criteria. The main parameters affecting the mechanical behavior of the connection have been singled out and their effects quantified by means of experimentation and numerical analysis. A synthetic model of the cyclic behavior has been formulated, implemented in a finite element format, and used in the analysis of timber structures in seismic conditions. The model has been verified with full-scale experimentation on a roof truss. Different reinforcing methods have been compared on the basis of experimental observation and calculated structural response. The study has shown that a satisfactory post-elastic response, comparable to that of new structures, may be reached for suitably retrofitted structures.