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Reinforced concrete (RC) bridge piers damaged after a strong earthquake are repaired. The damaged concrete and the steel reinforcement parts are replaced by rebar segments connected to the existing rebar parts by welding connections and by a self-compacting concrete jacket respectively. A modest transverse steel reinforcement, not sufficient to improve the seismic pier capacity, is used to simplifies the concrete cast in modest volumes. After the repair, a carbon fiber reinforced polymer (Carbon FRP) reinforcement is applied to enhance the pier ductility and the shear strength. Three RC circular columns, representative of piers, were repaired and reinforced by the proposed strategy to be tested in lab applying a deformation history due to a strong earthquake. The piers were able to sustain very strong seismic demand and therefore the proposed repair and retrofitting interventions are effective. The strain distribution of the Carbon FRP reinforcement was measured and discussed to increase the very modest database presented in the literature.

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.

Within SERA Horizon 2020 INMASPOL project, the paper reports the first results from seismic tests on shake table for a real scale reinforced concrete (RC) frame building with modified orthoblock brick wall infills. The building received innovative protection using polyurethane resin (PU) flexible joints (PUFJ) at the frame-infill interface together with the use of PUs for bonding glass fiber grids to the weak masonry substrate, to form Fiber Reinforced PU (FRPU) as emergency repair. The tests validated the advanced in-plane and out-of-plane infill performance under suitably designed seismic excitations. The PUFJ protection enabled the quick repair of the infill even after very high inter-storey drifts of the structure. In addition, the applied glass FRPU repair system efficiently protected the damaged orthoblock infills against collapse under out-of-plane excitation while they restored large part of their in-plane stiffness as well. In this paper, the performances of the FRPU applications under simulated seismic excitations are reported.

The effectiveness of Fibre Reinforced Cementitious Mortar (FRCM) as strengthening technique of masonry structures under seismic actions has been widely investigated by means of diagonal compression tests in the last decade. The results showed that the effectiveness of FCRM solution, based on the use of FRP grid embedded in mortar matrix, to increase the masonry walls shear capacity strongly depends on the axial stiffness of mesh reinforcement and on the mechanical properties of the matrix. The paper presents preliminary experimental results of tests carried out on specimens strengthened with a new strengthening solution based on the use of Fibre Reinforced Mortar (FRM) without the use of FRP grid. In particular, the strengthening system consists of an innovative high performance and high ductility mortar made by a mix of fibres spread in lime-based powder. The experimental program aims at investigating the soundness of such technique to increase the shear capacity of different masonry panels. In particular, the system was applied over limestone masonry walls with irregular texture, typical of existing buildings in Central Italy, and old-type clay brick masonry panels with regular texture, typical of existing buildings in the Northern Italy

Fiber Reinforced Polymer (FRP) composites have been widely used in past decades for the seismic upgrading of sub-standard reinforced concrete (RC) members and their effectiveness as a suitable strengthening technique for such kind of structural components has largely been proved. However, some concerns still arise with the effectiveness of such composite materials at high temperature, such as in the case of fire exposure. Furthermore, the use of FRPs requires a min- imum quality for the concrete substrate to avoid undesirable premature failure mechanisms. Usually, the replacement of the poor quality or damaged concrete cover of existing members with a new one is needed before the strengthening intervention. Current research is now moving towards the adoption of inorganic composite materials, such as Fiber Reinforced Cementitious Composite (FRCC), for repairing existing RC buildings and infrastructures as a replacement of the original concrete cover, due to its good durability properties and resistance to high temperature. The present study discusses the possibility of adopting such FRCC jacketing also for the seismic upgrading of existing shear critical RC columns. The experimental performance of RC columns strengthened with FRCC jacket- ing subjected to cyclic lateral loading and different axial load ratios is analyzed herein, and the experimental performance of FRCC and FRP jacketed columns is compared to point out the effectiveness of both retrofit solutions.