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This paper aims at investigating the matrix-to-textile stress transfer in a fabric reinforced cementitious matrix FRCM system, not bonded to any substrate, under shear loads. To this end, direct shear tests are performed on a basalt FRCM specimen introduced into an innovative properly designed four-hinge frame loaded by a universal testing machine. The role of the single components in the global shear behavior of the FRCM is experimentally analyzed. Digital image correlation (DIC) is adopted for evaluating both the displacement and strain fields as well as for detecting the damage. Furthermore, the shear response of the tested FRCM material is reproduced via an effective numerical approach that considers the nonlinear behavior of the mortar and the possible micro-mechanisms that arise between the textile and the matrix, introducing suitable interfaces joining the FRCM constituent layers, i.e. textile and mortar layers. Experimental outcomes highlighted the non-negligible influence of the matrix in the shear response of the composite, both in strength and stiffness. The proven DIC technique demonstrated to be suitable also for this novel test type, since it allows to obtain shear strains, location and amplitude of cracks with satisfying accuracy, such as to make direct shear tests results a benchmark to be used for numerical simulations. Numerical analyses are performed in order to verify the efficiency of the proposed model in reproducing the mechanical behavior of FRCM composites under shear loads and in describing the damage patterns during the loading process.

Seismic events recently occurred in Europe highlighted the vulnerability of unreinforced masonry structures, representing the majority of the built heritage, to earthquake-induced loads. In particular, the in-plane capacity of shear walls under seismic loadings appeared sensibly modest, both in terms of strength and ultimate displacement, and their failure mode sudden and brittle. Textile Reinforced Mortar (TRM) composites proved to be a proper strengthening solution for the seismic upgrade of such walls. With the aim of gaining a deeper knowledge on the behavior of historical walls retrofitted with TRM and subjected to compression-and-shear, this paper summarizes the results of an experimental campaign characterized by quasi-static cyclic shear-compression tests. The specimens under study reproduced the rubble stone masonry typical of vernacular structures of the UNESCO historical district of Lyon (France). Specifically, the work concerns a full scale masonry wall tested under loading until the development of diagonal cracks and than repaired by a composite constituted by a basalt textile embedded in a lime mortar matrix applied onto the external surfaces as a plaster. The use of a lime mortar plaster to reinforce the structural element permits the development of a solution compatible with the historical substrate. Experimental outcomes revealed how Basalt TRMs succeeded in improving the response of damaged vernacular wall, both in terms of strength and displacement capacity.

The monitoring of the structural integrity of road and transport infrastructures, and in particular of bridges and viaducts, has now become a priority issue, emphasized by the progressive decay of the characteristics of building materials, and deterioration of the works, which can cause damage and collapses with dramatic consequences. Following recent bridge collapses, including the "Polcevera Bridge"in Genoa, Italy, the Ministry of Infrastructures and Sustainable Mobility (MIMS) issued in 2020 specific Guidelines on the classification and risk management, safety assessment and monitoring of existing bridges. In this context, the creation of information catalogues for the mapping of structures and the implementation of innovative procedures for monitoring, appear to be a crucial step for public bodies and managing bodies end of assessing the state of the civil structures such as bridges and identifying the priorities maintenance actions. To date, monitoring operations of bridges are typically conducted through visual inspections, coring and punctual measurements carried out by specialized operators and, more rarely, through the use of Non-Destructive Technologies (NDT). On the other hand, in recent years, satellite radar remote sensing techniques have always been applied much more effectively at monitoring infrastructures, civil works, bridges and viaducts. Among the modern techniques, Multi-Temporal Satellite Radar Interferometry (MT-InSAR) is currently established as a reliable tool for control and monitoring of deformation phenomena of the soil and large-scale infrastructures, capable of returning information with millimetre accuracy. Moreover, the knowledge about structural materials, structural elements and defect state of the bridge collected by onsite inspection, is crucial to verify the stability to actual traffic and dynamic loads, not expected in the design phases. This work reports a methodology useful for evaluating the viaducts and bridges stability at the network-scale level, proposing a multi-level monitoring protocol from the integration of information from different sources and technologies, including ground-based, structural and remote sensing information. The activities are carried out as a part of the "MLAZIO"project, approved and supported by the Lazio Region. The first phase of this project involves the creation of a vector database for bridges mapping and localization, and the development of an informatic catalogue for the management of works, also including a view of the geo-eGovernment of the infrastructures. Such a system is developed on a platform interoperable in a Geographical Information System (GIS), already prepared for the expected integrations in the later stages of the project, which includes on-site inspections, NDTs ground-based and satellite remote sensing investigations. This project aims to create a reliable and effective methodology for the risk assessment and management of existent bridges. This study paves the way for optimizing the planning procedures of the interventions of ordinary and extraordinary maintenance activities by developing a prototype for the development of a Bridge Management System (BMS) at a regional level, increasing the resilience of the investigated infrastructures and bridges.

Masonry walls are particularly vulnerable against out-of-plane seismic actions. Steel tie-bars and crowing beams in reinforced masonry can prevent their overturning, but collapse may take place also by bending, leaf separation or disaggregation. Textile Reinforced Mortar (TRM) composites, comprising high strength fabrics and inorganic matrices, can be effectively applied to improve the seismic capacity of masonry load-bearing walls and infill panels. Nevertheless, a deeper knowledge on the dynamic response and ultimate capacity of retrofitted walls still needs to be gained before TRM systems can be confidently used in engineering practice. This work describes a shake table test carried out on two full-scale wall specimens, one made of regular tuff blocks and one of two leaves of rubble stones, subjected to seismic out-of-plane vertical bending. The walls were tested unreinforced, repaired and strengthened with TRMs and tested again. A unidirectional textile of ultra high tensile strength steel was used on the tuff wall, whereas a bidirectional basalt mesh was applied over the entire surface of the stone wall, with the addition of transversal steel connectors. The responses of the specimens before and after retrofitting are compared to show the improvement in terms of acceleration and displacement capacity entailed by TRM retrofitting and the modification of, deflection profiles, failure modes, damage development and dynamic properties. Test outcomes prove the effectiveness of TRM composites for the protection of existing masonry structures, including architectural heritage, in earthquake prone areas and provide information on the reliability of analytical predictions for seismic assessment.

Recent earthquakes have dramatically shown the seismic vulnerability of existing masonry structures and highlighted the urgent need of developing suitable strengthening solutions. In order to gain an improved understanding of the seismic response of masonry constructions and of the most appropriate technologies for their retrofitting, a shake table test was performed on a full-scale U-shaped tuff masonry structure, provided with an asymmetric plan with openings and with an inclined roof. The specimen was tested unreinforced and then repaired and retrofitted with composite reinforced mortar (CRM), comprised of a glass fibre reinforced polymer mesh applied with a lime mortar. Natural accelerograms were applied with increasing scale factor to collapse. Results provided information on the dynamic behaviour of masonry structures strengthened with CRM and on the enhancement of seismic performance provided by the retrofitting work.

The out-of-plane vulnerability of masonry walls plays a crucial role in the seismic response of existing structures. Depending upon mechanical properties and section morphology, collapse may occur by the onset of a mechanism or, as historic constructions often exhibit, leaf separation, disaggregation or sliding. In these latter cases, structural analyses based on rigid-body mechanics, may overestimate the seismic capacity. The distinct element method (DEM), which represents masonry as an assembly of discrete blocks and nonlinear interfaces, could instead be used. Nevertheless, it is more complex and requires more input parameters, so it is still barely applied in engineering practice. In this paper, the seismic out-of-plane response of masonry walls was modelled with DEM. A shake table test on a two-leaf rubble stone masonry wall and a single-leaf wall in tuff blocks was simulated through nonlinear dynamic analyses. The mechanical properties of joints were calibrated on the basis of dynamic identification under low intensity white noise input, leading to a good prediction of the seismic response. Then, they were further tuned based on surveyed crack pattern for an improved matching between experimental results and numerical postdictions. Finally, the results provided by limit analysis were discussed in the light of DEM simulations.

Mortar-based composites have proved effective for the external strengthening of existing structures and have already been widely applied in the field. To date, however, their long-term performances have not been sufficiently investigated, even if they are of the utmost importance for mitigating the risks and the costs associated to damage and repair/substitution. This is crucial for the sustainability of the building stock and of the rehabilitation measures developed for its lasting safeguarding. This paper collects the studies performed on the durability of Steel Reinforced Grout (SRG) systems, comprising ultra-high tensile strength steel textiles and inorganic matrices. Brass and zinc coated steel cords have been tested after accelerated artificial aging in saltwater solutions, salt mist, acid solutions and freeze-thaw cycles. Laboratory investigations include tensile and bond tests. Available results are discussed to make the point on current state-of-knowledge, contribute to the improvement of artificial aging protocols and test procedures, and promote future research and standardization activities.

Fabric reinforced cementitious matrix (FRCM) composites are widely used for retrofitting existing structures, especially in earthquake prone areas. After nearly two decades of scientific studies, experimental evidence proves their effectiveness for enhancing the ultimate strength and displacement capacity of masonry walls. There remains a need to develop design guidelines for use in rehabilitation practice. This paper proposes a method for the design of the shear strengthening of masonry walls with FRCM, and provides the calibration of the partial coefficients for the calculation of the ultimate limit state. The design relationships are validated on the basis of an experimental database that includes 72 tests and are suitable for engineering purposes. The possibility of applying the same design format to the walls strengthened with composite reinforced mortar (CRM) is investigated, by considering 54 additional tests and comparing to FRCM retrofitted ones. Finally, the enhancement of displacement capacity achieved with FRCM and CRM, which is particularly useful for seismic retrofitting, is estimated, and a design value for the ultimate drift capacity is provided.

Fabric reinforced cementitious matrix (FRCM) composites, made of high strength textiles externally bonded with inorganic matrices, experimentally proved effective to enhance the capacity of masonry walls. With the aim of fostering the transfer of knowledge from scientific research to engineering practice, this paper proposes an approach for the design of the out-of-plane flexural strengthening of masonry walls by FRCM systems. The mechanical properties of the reinforcement are derived by combining the results of tensile tests on textile specimens and FRCM-to-substrate shear bond tests. An expression for the preliminary design of the reinforcement is proposed, according to a limit analysis approach, based on tensile and bond strength of FRCM. Whereas, for structural assessment, strain compatibility is enforced, and the bending moment capacity of the reinforced wall is based on FRCM stiffness, tensile and bond strains, consistently with existing building codes. An estimate of the out-of-plane displacement capacity is also developed, which is particularly useful in seismic assessment. A wide experimental database is used to validate theoretical relationships, tune calibration coefficients and derive safety factors, in accordance with the design-by-testing framework of Eurocode 0 for ultimate limit state design.

Masonry walls are particularly vulnerable against out-of-plane seismic actions. Textile Reinforced Mortar (TRM) composites, made of high strength fabrics embedded inside inorganic matrices, can be efficiently integrated with traditional strengthening techniques to improve their seismic capacity, as demonstrated by a number of experimental investigations. Nevertheless, apart from the ACI 549.4R-13 guidelines, no design instructions addressed to practitioners have been developed so far. This paper proposes an approach for the evaluation of the out-of-plane flexural capacity of masonry walls reinforced by externally bonded TRM systems. The mechanical properties of the reinforcements are derived by combining the results of tensile tests on textile specimens and TRM-to-substrate shear bond tests. The bending strength is evaluated through a cross-sectional analysis based on strain limit states to fulfil compatibility. Analytical predictions are in good agreement with experimental results, indicating that the method is suitable for engineering design purposes.