Lateral Performance of As-Built and Retrofitted Timber Diaphragm Fastener Connections

The in-plane stiffness of timber diaphragms commonly found in vintage unreinforced masonry (URM) buildings is largely determined by the rigidity of the fastener connections. Currently in the literature, however, there is limited experimental data on the behavior of floorboard-to-joist connections, and consequently the aim of the present study was to supplement that knowledge. The existing data provided the paramount input parameters for the finite element modeling of timber diaphragms, in order to model and validate the results obtained from the experimental testing of full-scale timber diaphragms. The floorboard-to-joist connections were extracted from two vintage URM buildings and were tested using three different test setups to address various realistic loading configurations. In addition, the floorboard-to-joist connections were improved using new nails or new screws. Specimens comprising plywood or fire-rated gypsum-board panels connected to the salvaged floorboards or joists were also tested as a method for improving the overall diaphragm lateral behavior. The experimental study of timber diaphragm fastener connections consisted of 43 samples, of which the results are presented here.