Finite element modelling of the nonlinear load-slip behaviour of full-scale timber-to-concrete composite T-shaped beams

Timber-to-concrete flooring systems have exponentially increased in the last decades and have attracted many researchers and constructors. They are employed in both new modern constructions and renovations of residential and non-residential buildings with the development of lightweight construction and rehabilitation programs. Nevertheless, this requires a rapid progress in gaining the needed tools and methods to design safely and properly such full-scale composite systems. This article is devoted to the development of new analysis techniques and predictive numerical models dedicated to screwed connections at large scale level. The aim is to investigate the nonlinear structural behavior of full-scale screwed timber-to-concrete beams. The main objective is to identify and validate an appropriate numerical finite element model in the context of full-scale applications with large number of screws, using the so-called verification and validation methodology (V&V). First, the results from different modelling techniques are critically discussed in the context of middle scale timber-to-timber samples assembled with two screws. These preliminary results highlight the limitations of the existing modelling techniques. Finally, an efficient and predictive numerical approach is specifically developed and validated experimentally through a full-scale timber-to-concrete composite T-shaped beam assembled with 46 SFS-screws.