Earthen claddings in lightweight timber framed buildings: An experimental study on the influence of fir boards sheathing and GFRP jacketing

The aim of this research was to investigate the mechanical performance of an earthen massive cladding, recently used for external/internal layers in Platform Frame technology, through an extensive experimental campaign. The masonry is built with extruded unbaked earth blocks and characterized by dovetail horizontally staggered bed joints. The wall is secured to the structural timber studs through 45 degree-angled fir boards sheathing panels, fixed with steel connectors, and finished with an external plaster with an embedded Glass Fibre Reinforced Polymer (GFRP) mesh, wrapping the whole masonry. The influence of the fir board panels and GFRP jacketing on the mechanical behavior of the earth blocks masonry is investigated and compared with the results obtained for the unreinforced configuration (bare wallettes) in (Stazi et al., 2020). The experimental program consisted of compression, diagonal compression and combined shear-compression tests on 18 wallettes. Digital Image Correlation technique was also adopted to investigate the full field strain maps. The results showed that under compression all the samples (with and without reinforcements) behave as a series of independent slender columns, without significant differences among reinforcement type. Both diagonal compression and shear with compression tests revealed the optimal behavior of GFRP plaster reinforcement that increases the strength values and thanks to an effective confinement effect, limits the out-of-plane bending and determines a monolithic response of the wall.