Analytical model for the in-plane resistance of masonry walls retrofitted with steel fiber reinforced mortar coating

Recent experimental tests showed the ability of Steel Fiber Reinforced Mortar (SFRM) coating to significantly improve the in-plane resistance of masonry walls and buildings. International and national structural codes, such as the fib Model Code 2010 (MC2010) and the Italian building code (NTC2018), have introduced fiber reinforced cementitious composites as structural materials for designing structural elements. However, the use of these materials as jacketing of masonry buildings is currently not taken into considerations by any design guidelines as potential seismic retrofitting intervention. Besides the limited availability of experimental data, this gap in design recommendations is closely related to the lack of design equations able to provide the shear and flexural resistance of retrofitted masonry elements. The present work aims at filling this gap by proposing code-oriented formulations for calculating the in-plane lateral resistance of walls strengthened by SFRM overlays. The model has been mainly validated by comparison with the numerical results obtained from a comprehensive parametric study presented and described in the paper. Finally, an example is presented to show a practical application of the model.