PSI - Issue 44

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

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CAM ® technology creates a closed pre-stressed bracket using ribbon. In this way brittle mechanisms, due to lack of transverse reinforcement in beams, columns and joints, can be avoided. With accurate CAM ® technology design, it is possible to give the structure ductile behaviour and achieve shear-flexure hierarchy also in building retrofitting which is necessary for the correct seismic behaviour of the RC building, Bianco et al. (2017). Once ductile mechanism has been achieved to correct brittle mechanism, it is necessary to use CAM ® technology to give bending capacity to the columns through reinforcement and deformation capacity in order to achieve plastic hinge in beams. In addition, CAM ® technology is the only one that allows shear reinforcement in slab thickness beams and beam-column node confining. Where joints are concerned, experimental evaluation shows that pre-stressed stirrups give better results than brackets (calculated in accordance with NTC2018 requirements), De Risi et al. (2019).

a

b

Fig. 3. (a) CAM® arrangements on RC structure and (b) evaluation test on CAM® joint reinforcement

The CAM ® System has important advantages compared to other available technologies. Firstly, it increases the performance of the structure in the elastic phase (for the pre-tensioning effect) and in the plastic phase, without altering the distribution of mass and stiffness in the structure. High resistance stainless steel is the material used for the ribbons. This means high corrosion resistance and chemical compatibility with surface coating and durability. The dry installation allows quick assembly and compatibility with any working temperature. Secondly, the preparation of the surfaces only needs local demolition of the plaster without further surface treatments. The flexibility of ribbons makes features which are “sewn” onto the building, by-passing floors and architectural or decorative finishes. The Ministry of Cultural Heritage approves of the CAM ® System because it’s reversible and minimally invasive, thus matching the need for conservation and the necessity of strengthening.

Table 1. comparison between common strengthening technologies

technique comparison

Active system

Mass and weight alteration

Surface preparation

Compatibility with system and finishes

Type of installation

Reversibility invasiveness

CAM® System Steel jacketing

yes

no no

low low low high

high low low low

high high low low

low low high high

dry dry wet wet

no no no

Concrete jacketing

yes

FPR

no