PSI - Issue 44

Giorgio Giacomin et al. / Procedia Structural Integrity 44 (2023) 610–617

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Giorgio Giacomin et al. / Structural Integrity Procedia 00 (2022) 000–000

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means of floor strips using the SRG System (Steel Reinforced Grout) technology made of ultra-high-strength UHTSS galvanised steel fabrics applied with hydraulic lime-based structural mortars. In particular, a system consisting of a 30 cm thick, single-layer, high-strength UHTSS STEEL NET G 135 galvanised steel band, applied with LIMECRETE M15 hydraulic lime-based structural mortar and UHTSS SFIX G10 galvanised steel bows connectors with a pitch of approximately 50 cm, installed with RESIN 90 epoxy resin, was used. The phases envisaged for carrying out the intervention are as follows: 1. removal of the existing plaster and consolidation of the damaged areas with LIMECRETE hydraulic-based mortars. Provide for the rounding of the edges over which the fabric will pass with a minimum radius r = 2.5 cm; 2. laying the SFIX G10 steel arch connectors with RESIN 90 epoxy resin; 3. creation of the levelling lanes with LIMECRETE M15 type hydraulic lime mortar for laying the fabric, after wetting the substrate; 4. application of the ultra-high-strength UHTSS galvanised steel unidirectional fabric STEEL NET G 135 in the mortar while still fresh. Minimum longitudinal overlap 20 cm; 5. unfolding the SFIX G10 bows connectors for anchoring the reinforcement and impregnating with resin type RESIN 90 on the reinforcement; 6. cover the fabric with the final layer of mortar such as LIMECRETE M15. Minimum total thickness of the two layers of about 20 - 25 mm; 7. possible finishing operations. 10. FRP System On the masonry walls and the brick masonry pillar relating to the second deck, the reinforcement system adopted involved the use of carbon fibre fabrics applied in situ with two-component epoxy adhesives, CFRP (Carbon Fiber Reinforced Polymer) system. In particular, for the anti-seismic structural reinforcement of the internal wall faces, shown in red in Fig. 12, strips of C-SHEET 240/300 unidirectional carbon fabric in Class 210C and 30 cm in height were applied with RESIN 75 epoxy resin for the entire height of the walls, with the dual purpose of reinforcing the wall panels against both out-of plane and in-plane pressure-deflection phenomena. In addition, the masonry was also reinforced in shear by using St. Andrew's crosses made of two-directional strips of CTB 240/300 carbon fibre fabric in Class 210C and 20 cm high impregnated with RESIN 75 epoxy adhesive. Finally, AFIX 10 aramid fibre staple connectors of Φ 10 mm diameter were installed at the intersections of the fabrics. The following are the application steps of the reinforcement system: 1. Treatment of the existing substrate with cleaning and eventual consolidation of the same using LIMECRETE lime based mortars; 2. application of a levelling layer in mortar, typically LIMECRETE M15 hydraulic lime. 3. application of carbon fibre fabric strips according to FRP cycle: • impregnation of the surface with solvent-based epoxy primer RESIN PRIMER; • application of epoxy adhesive RESIN 75; • laying of unidirectional vertical and horizontal carbon fabric type C-SHEET 240/300/20 with a height of 20 cm (3.a), FRP 210C class, and bidirectional St. Andrew's cross fabric type CTB 240/360 with a height of 20 cm (3.b), FRP 350/2800C class • final impregnation of the fabric with RESIN 75 adhesive. Minimum overlap: longitudinal 15-20 cm, transverse 2 cm. 4. installation at the intersections of the fabrics, of AFIX 10 aramid fibre staple connectors: • drilling the 14 - 16 mm diameter hole before laying the fabric; • grouting of the through-hole connector with RESIN 75 after cleaning the hole; • after spreading the fabric, flaking the staple onto the fabric, for at least 15 cm, and impregnating with RESIN 75. 5. possible finishing with civil plaster, after quartz dusting on resin while still fresh.