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The cast in place floors of existing buildings realized in Italy in the ‘60–70’ years are commonly made by longitudinal beams and hollow clay bricks with a top deck without internal reinforcement. Thus, they are unable to properly guarantee the load distribution function over structural members which is strongly required in case of seismic actions. Furthermore, the deck thickness of such horizontal structures is commonly less than the minimum value given by current codes (≥40 mm) in order to assume the floor as rigid in plan. The effectiveness of an innovative system, based on the use of Fibre-Reinforced Cementitious Composite (FRCC), is investigated in the paper as a strengthening technique of these existing floors. Three point bending tests on two full scale cast in place reinforced concrete (r.c.) floors have been carried out: one specimen was tested in the ‘‘as built’’ configuration; one specimen was strengthened with a new FRCC deck, about 2 cm thickness made by fibre-reinforced, shrinkage-compensated, high-strength, high-ductility, highly-fluid cementitious mortar. The main aspects related to the application procedure of the system, the experimental test setup, as well as the experimental results in terms of crack pattern, strength and deformation of the specimens are herein presented and discussed.

In last decades, several experimental tests were carried out in order to investigate the effectiveness of strengthening systems by using FRP as a confinement technique of masonry columns. Recently, in order to solve problems related to the compatibility of FRPs with masonry members, a new technique based on the use of inorganic matrix rather than resins has been developed (FRCM-Fabric Reinforced Cementitious Matrix). In order to investigate the structural effectiveness of FRCM systems, an experimental program was carried out on full-scale masonry columns by means of uni-axial compression tests. In particular, the effectiveness of FRCM systems based on the use of A.R. glass fibre grid embedded in lime-based mortar with high mechanical properties has been investigated. Test programme, material mechanical properties, and test setup are herein presented along with the preliminary experimental results in terms of load and ductility capacity of a control and strengthened specimen. A preliminary comparison between the performance of FRP and the strengthening systems is also reported.

A study on the dynamic response of one-story building, made by yellow regular Neapolitan blocks and mortar with poor mechanical properties in a traditional texture of existing masonry structures is herein illustrated. The seismic response of the masonry building has been investigated by means of shake-table tests on 1/2-scale model. Seismic inputs of recent earthquakes Italy (e.g. L’Aquila 2009, Amatrice 2016) were used in order to investigate the seismic behavior of the sample. The paper reports the main aspects related to the specimen design procedure, the experimental test setup, experimental outcomes, crack patterns and failure mechanism of the as-built specimen.

Existing masonry buildings often exhibit a brittle behavior during seismic events due to the reduced in-plane shear capacity of piers. Inorganic composite materials are widely used for the seismic upgrading of masonry walls capacity, thanks to the good breathability and compatibility with the substrate. This work presents the results of an experimental program carried out on 17 limestone masonry panels with irregular texture typical of L’Aquila area and tested under diagonal compression. Three panels were used as control specimens; the remaining panels were strengthened with Fiber Reinforced Cement Mortar (FRCM) with anchors and two different lime-based mortars, one cement-free and one with a small cement content ratio, and coupled with two different grids (GFRP grid 40 × 40 mm and BFRP grid 6 × 6 mm). Single-sided and double-sided strengthening configurations were adopted, to investigate the reduction in strengthening effectiveness in the case of single-sided applications. The results showed that the FRCM system allowed a capacity increase by 65% in single-sided configuration and 140% in double-sided configuration. The matrix cement-content did not affect significantly the results. Conversely, the use of the BFRP grid, characterized by a 6 mm spacing, promoted the development of premature delamination problems.

Recent studies, as well as past earthquake experience, demonstrated that slender unreinforced masonry infills are significantly vulnerable with respect to out-of-plane actions. The out-of-plane collapse of infills significantly increases the repairment and refurbishment costs after earthquakes of reinforced concrete buildings and, above all, is highly detrimental for human life safety. For this reason, the interest on the experimental and numerical studies dedicated to the assessment of the effectiveness of out-of-pane repairing, strengthening and reinforcement techniques of masonry infills is growing, especially in recent years. In this work, experimental tests performed at the Department of Structures for Engineering and Architecture of University of Naples Federico II to characterize the out-of-plane response of one-way spanning unreinforced and reinforced masonry infills are presented. Namely, an out-of-plane test is performed on an “as-built” specimen, whose performance is compared with the experimental response of specimens strengthened by applying two different techniques, a fiber reinforced polymer and a fabric reinforced cementitious mortar. In addition, after test, the as-built specimen is repaired by applying the fiber reinforced polymer and tested again. The response of the repaired specimen is presented and discussed.