This paper deals with the conception and characterization of an innovative connection for cross-laminated timber (CLT) panels. The connection is designed to provide an adequate level of dissipative capacity to CLT structures also when realized with large horizontal panels and therefore prone to fragile shear sliding failure. The connector, named X-bracket, has been theorized and designed by means of numerical parametric analyses. Furthermore, its cyclic behavior has been verified with experimental tests and compared to that of traditional connectors. Numerical simulations of cyclic tests of different CLT walls anchored to the foundation with X-brackets were also performed to assess their improved seismic performances. Finally, the analysis of the response of a 6 m × 3 m squat wall demonstrates that the developed connection provides good ductility and dissipation capacities also to shear walls realized with a single CLT panel.

Three innovative massive wooden shear-wall systems (Cross-Laminated-Glued Wall, Cross-Laminated-Stapled Wall, Layered Wall with dovetail inserts) were tested and their structural behaviour under seismic action was assessed with numerical simulations. The wall specimens differ mainly in the method used to assemble the layers of timber boards composing them. Quasi-static cyclic loading tests were carried out and then reproduced with a non-linear numerical model calibrated on the test results to estimate the most appropriate behaviour factor for each system. Non-linear dynamic simulations of 15 artificially generated seismic shocks showed that these systems have good dissipative capacity when correctly designed and that they can be assigned to the medium ductility class of Eurocode 8. This work also shows the influence of deformations in wooden panels and base connectors on the behaviour factor and dissipative capacity of the system.

The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB) sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerical model was calibrated on experimental results and the dynamic non-linear behavior of a case-study building was assessed. Numerical results were then used to estimate the proper behavior factor value, according to European seismic codes. Obtained results demonstrate that this innovative system is suitable for the use in seismic-prone areas thanks to the high ductility and dissipative capacity achieved by the bracing system. This favorable behavior is mainly due to the fasteners and materials used and to the correct application of the capacity design approach.

Experts are aware that the critical and until now unsolved problem of timber wall buildings lies in proper anchoring of the structure to foundations. Geometric inaccuracies and discrepancies between the concrete surface and the timber structure often lead to incorrect alignment of walls, which is normally solved with provisional and inaccurate solutions, in contrast with prefabrication. However, the most important issue is the compromised durability of timber due to rising dampness and fungicide attack, which are a result of inaccurate waterproofing as moisture is absorbed and trapped at the wall base. Difficulties in restoring such damages arise together with maintenance costs of the structures. This work provides an overview on the crucial problems that affect the anchoring of timber structures to foundations. Disadvantages of traditional techniques are presented and critically discussed. An innovative aluminium bottom rail designed for Cross-Laminated Timber, light-frame and Blockhaus technologies is presented, evidencing main structural properties and capacities in assuring timber durability and long-lasting fixing. This aluminium beam is made of an extruded profile with shape and size optimized for load-bearing capacity and lateral stability. Special grooves at both sides are designed to obtain fast and efficient fixing of shear-resisting plates and hold-downs. Main results from latest experimental campaign are given to characterize the system in terms of load-bearing capacity and case-study applications in newly-realized timber buildings are presented. Finally, a proposal for possible restoring intervention to replace the damaged timber at the base of the wall is hypothesized.