PSI - Issue 44

2

Marianna Leonori et al. / Procedia Structural Integrity 44 (2023) 1022–1029 Author name / Structural Integrity Procedia 00 (2022) 000–000

1023

structural use of stainless-steel ribbon which is pre-stressed at the time of application. The ribbon is installed according to closed-loop configuration and it can also be set in several overlaps.

Fig. 1. EDIL CAM Sistemi ® technology applied to masonry and RC structures

The CAM ® System (using simple basic components like pre-stressed strips, draw pieces and L-plate) is able to “sew” the masonry structure therefore preventing the activation of both global and local collapse mechanisms and create a “box effect” that allows optimal protection against seismic action in masonry buildings. The ribbons across and in the wall create a mechanical transverse tie transforming the behaviour of a double-facing wall into one connected wall. Horizontal CAM ® slings create widespread micro-tie rods. At the intersections of the wall CAM ® mesh allows constraints to be created, avoiding local collapse mechanisms such as the overturning of the whole facade or a portion of it. Another connection needed for optimal seismic behaviour is between the floors and the wall. This means that sliding of the joists from the support must be avoided and floor kerbs must be connected to masonry walls. All these constraints can be created using CAM ® ribbon, Dolce et al. (2001). Therefore, this type of “sewing” allows the masonry structure to be “packaged” giving a beneficial tri-axial compression stress state. Improving local seismic response by CAM ® connection and creating “box behaviour” means including as many elements as possible of the entire building involved in the collapse mechanism in order to obtain “global ductile behaviour”, Spinella et al. (2014). CAM ® mesh also allows masonry strengthening in plane and out of plane with respect to shear and flexural seismic actions - the horizontal ties can be calibrated for shear reinforcement and the vertical ones for bending, Leonori and Vari (2017). Calculations are in accordance with NTC2018 requirements, following the rules of reinforced masonry to evaluate both the increase in resistance and deformation, Leonori and Vari (2019).

Fig. 2. CAM ® mesh avoids global and local collapse in masonry building

In existing reinforced concrete frame structures, premature collapse is strictly connected to pre-emptive brittle failure (shear “local” failure of joints, columns or beams) or to “global” brittle mechanisms (such as soft storey).