Description
The application of timber-based strengthening solutions to existing wooden and masonry structures, combines several benefits, such as reversibility, compatibility, lightness, sustainability, affordability, and effectiveness. With specific reference to existing timber floors, the superposition of plywood panels fastened to the sheathing has proved to be an excellent method to enhance the seismic response of such structural components, combining a great improvement of in-plane strength and stiffness, with a considerable increase in their hysteretic energy dissipation.
In order to promote the use of this retrofitting method in practice, this work firstly presents the implementation of calculation tools supporting the design and advanced numerical modelling of timber diaphragms strengthened with plywood panels. The suite of tools allows to first estimate the full nonlinear, cyclic in-plane response of the strengthened diaphragms, starting from the geometrical and material properties of the existing sheathing and the plywood overlay, as well as the mechanical characteristics of the fasteners. In a second step, it is possible to transform such estimated in-plane response into a constitutive law for finite element modelling and perform advanced numerical simulations, by means of a user-supplied subroutine developed for DIANA FEA software. Relevant calculation examples show the accuracy and potential of this integrated approach, which also found application in an ongoing research study on the evaluation of the influence of retrofitted diaphragms’ stiffness on the seismic out-of-plane response of masonry gables, as part of the ERIES-SUPREME project, supported by the Engineering Research Infrastructures for European Synergies (ERIES).
