FAQ

FRP systems (Fiber Reinforced Polymer) are composite materials made of high-strength, high-modulus fibers—such as carbon or glass—impregnated with epoxy resins. They are used for the structural strengthening of reinforced concrete and masonry elements to increase flexural, shear, and confinement capacity, without significantly altering the weight or geometry of the structure.

Carbon fiber strengthening is particularly suitable when a significant increase in mechanical performance is required with extremely small thicknesses. It is an ideal solution for localized interventions on beams, columns, and structural joints in good condition, where minimal invasiveness is essential.

FRP systems offer high mechanical strength with very low weight, allow for rapid installation, provide excellent durability, and are not subject to corrosion. Compared to traditional methods, such as reinforced concrete jacketing, they do not significantly increase seismic mass or cause relevant geometric changes.

Yes, FRP systems are regulated by CNR-DT 200, the NTC 2018 (Italian Building Code), and the related application guidelines. They can also be qualified through a Technical Assessment Certificate (CVT) and may be accompanied by additional certifications such as ETA and EPD.

Design is carried out according to CNR-DT 200 guidelines and includes checking flexural and shear contributions, analyzing failure modes, and verifying the effective anchorage length. Particular attention must be paid to preventing debonding of the composite.

Debonding is the detachment of the FRP reinforcement from the substrate to which it is bonded and is one of the main failure mechanisms. It can be prevented through proper surface preparation, correct use of resins, and adequate design of anchorage lengths.

Carbon fiber laminates are stiffer and are used for linear strengthening applications, such as flexural reinforcement of beams. Fabrics, on the other hand, are more flexible and better suited for complex geometries, making them ideal for columns, joints, and irregular surfaces.

The installation of FRP systems involves well-defined steps: surface preparation, primer application, resin spreading, placement of the reinforcement, and its impregnation. Proper execution of the application cycle is essential to ensure system performance.

No, FRP systems require dry substrates, as moisture compromises resin adhesion and can significantly reduce the durability of the intervention.

FRP systems are better suited for localized strengthening of structural elements with sound substrates and high performance requirements, whereas CRM systems are preferable for widespread interventions on deteriorated masonry, where improving cohesion and overall structural behavior is necessary. The choice should always be based on a careful assessment of the substrate condition, structural objectives, and design constraints.

CRM (Composite Reinforced Mortar) is a strengthening system consisting of a composite mesh, connectors, and structural mortar. It behaves like a three-dimensional reinforced coating capable of significantly improving the strength and overall response of masonry.

CRM is particularly suitable for degraded, irregular, or low-strength masonry, such as rubble or multi-leaf (“a sacco”) walls. It is one of the most effective solutions for the seismic upgrading of existing buildings.

CRM systems provide a distributed and composite strengthening effect, improve durability compared to traditional solutions, and ensure better compatibility with existing materials—especially in historic buildings. They also increase structural ductility, enhancing performance under seismic actions.

Yes, CRM increases shear strength, energy dissipation capacity, and the out-of-plane behavior of masonry, helping to reduce the risk of brittle collapse during earthquakes.

The typical thickness of a CRM system ranges from 30 to 40 mm per side, although it may vary depending on the required performance and the certified system used.

Connectors are designed based on their tensile strength, anchorage length, and required density per square meter. They are essential to ensure the three-dimensional behavior of the strengthening system.

The number of connectors typically ranges between 3 and 6 per square meter, depending on masonry characteristics and design specifications.

CRM uses preformed meshes and embedded connectors within structural mortar and is more suitable for widespread interventions, while FRCM employs dry or pre-impregnated meshes with an inorganic matrix and is better suited for localized, less invasive strengthening due to its thinner profile.

The application of a CRM system involves substrate preparation, installation of the mesh and any corner reinforcements, drilling for transverse connectors, and subsequent application of structural mortar, fully embedding the mesh to ensure a composite structural behavior.

The substrate should be adequately saturated but free of standing surface water, to ensure proper adhesion of the mortar.

CRM systems can be applied in winter conditions provided that the temperature does not drop below +5 °C and that appropriate protective measures are taken to prevent freezing and ensure proper curing of the mortar.

CRM is suited for widespread interventions on existing and deteriorated masonry, while FRP systems are preferable for localized strengthening of structural elements in good condition. The choice should always be based on a preliminary assessment of the substrate and the structural objectives.

Reinforced repointing is a strengthening technique for exposed masonry that involves inserting strands and connectors into the mortar joints. It improves mechanical performance without altering the architectural appearance.

Reinforced repointing is particularly suitable for exposed masonry, listed historic buildings, or whenever structural performance needs to be improved without affecting the wall’s architectural appearance. It is ideal for degraded yet still recoverable masonry.

The main advantage lies in integrating the reinforcement within the existing masonry without increasing its thickness or altering its surface appearance. Compared to CRM or FRP systems, it is less invasive and more compatible with historic buildings, while still providing a distributed improvement in performance.

The RETICOLA system uses strands and connectors inserted into the masonry joints to create a distributed three-dimensional grid. This configuration improves shear strength, enhances internal cohesion, and promotes better stress distribution, making the masonry more stable and resistant.

Yes, it increases the masonry’s capacity to withstand horizontal actions and improves system ductility. This reduces the risk of brittle failure mechanisms and contributes to safer performance during seismic events.

RETICOLA is applied on a single face of the masonry wall. RETICOLA TWIN extends the intervention to both faces, improving transverse connection. RETICOLA PLUS combines reinforced repointing on one side with a CRM system on the other, enhancing structural performance while preserving the appearance of the existing façade.

Yes, it is one of the most compatible techniques for conservation work, as it only affects the joints without altering the masonry’s appearance. When executed with lime-based mortars, it ensures breathability and chemical-physical compatibility.

The process involves raking out the mortar joints, thorough cleaning, inserting the strands, and repointing with structural mortar. Proper execution is essential to ensure the effectiveness of the system.

The technique is suitable for stone, brick, or mixed masonry, provided they have a sound texture with elements that are still intact and well-arranged. It is not suitable in cases of complete disintegration of the wall face.

Reinforced repointing is preferable when it is necessary to preserve exposed masonry, while CRM is better suited for more extensive structural interventions requiring a higher performance increase.

Soffit failure is a common phenomenon in hollow clay block (beam-and-block) slabs, consisting of the detachment of the infill blocks or plaster from the underside. It is dangerous because it can occur suddenly, causing falling debris and posing a safety risk.

Anti-soffit-failure systems involve installing a safety mesh anchored to the slab structure. In case of detachment, the mesh retains the materials, preventing them from falling.

No, it is a safety system rather than a structural strengthening solution. It does not increase the load-bearing capacity of the slab but reduces the risk to users in the event of detachment.

It is recommended in the presence of deteriorated slabs, older buildings, or uses with high occupancy—such as schools, offices, and public facilities—in order to reduce risk and ensure adequate safety levels.

Anti-soffit-failure systems can be applied to reinforced concrete, steel, and timber slabs, provided that effective anchorage to the structural elements can be achieved.

The system is designed based on the slab characteristics, selecting the appropriate type of mesh and anchors with sufficient load-bearing capacity for the expected loads. The layout of the fixings is crucial to ensure safety.

Anchors ensure the connection between the mesh and the load-bearing structure of the slab and are the most critical component of the system. They must be properly designed to ensure the mesh can support the weight of detached materials.

The intervention is generally minimally invasive, as it is carried out on the underside of the slab and does not alter the load-bearing structure. It can be completed quickly and often without interrupting the use of the spaces.

Yes, in most cases the installation is carried out without significant demolition, making it particularly suitable for buildings in use.

Anti-soffit-failure systems provide local safety measures and do not replace structural strengthening. If the slab has insufficient load-bearing capacity, structural strengthening is required; if the issue is the risk of detachment, an anti-soffit-failure system is the most effective solution.

Seismic dampers are devices designed to absorb and dissipate the energy generated by earthquakes, reducing the forces transmitted to the structure. Their use improves seismic performance by limiting damage and deformations.

Seismic dampers are activated when the structure undergoes significant displacements, as occurs during an earthquake. Under these conditions, they dissipate energy through hysteretic or elasto-plastic mechanisms, reducing accelerations and internal forces in structural elements.

The use of dampers is particularly advantageous when improving safety without invasive intervention on the existing structure is desired. They are ideal for precast buildings, industrial facilities, or structures in operation where major works are to be avoided.

No, in most cases dampers do not alter the structural scheme or overall stiffness. Instead, they introduce a dynamic behavior that activates only during seismic events, leaving normal performance unchanged.

Dampers reduce seismic demand rather than increasing structural capacity. This approach allows for less invasive, faster, and often more cost-effective interventions compared to traditional strengthening techniques.

Dampers are mainly used in precast concrete buildings, industrial warehouses, logistics facilities, and generally in structures with weak or insufficient connections between elements.

Non-linear dampers activate only after certain deformation thresholds are exceeded and are more effective at dissipating energy during strong seismic events. Linear devices, on the other hand, respond proportionally to displacement and are less selective.

Dissipative devices absorb seismic energy and reduce stresses, while seismic restraints prevent movements or loss of support. Advanced systems combine both functions, ensuring both energy dissipation and secure connections.

SAFE+ devices connect beams, columns, and panels, improving the overall system behavior. During an earthquake, they dissipate energy and prevent disconnection or loss of support—one of the main causes of collapse in precast buildings.

SAFE+ Model A exhibits non-linear dissipative behavior and also functions as a fuse and mechanical restraint, activating progressively as displacement increases. Model B has a non-linear elastic behavior with a more gradual and controlled response, and is selected based on design requirements.

Yes, dampers must comply with UNI EN 15129, which defines the performance requirements for seismic devices. They must also be integrated into design according to NTC 2018.

Yes, one of the main advantages of dampers is their suitability for installation on existing buildings without invasive structural intervention, making them ideal for seismic retrofitting of buildings in use.

These devices are designed to activate only when specific displacement thresholds are exceeded. This means they do not interfere with normal structural movements, such as thermal expansion, but activate effectively during significant seismic events.

Design takes into account the dynamic response of the structure, seismic demand, and device characteristics. It is essential to correctly model the non-linear behavior of dampers and verify connections and anchorage systems.

Dampers are ideal when the goal is to reduce seismic demand and limit intervention invasiveness. Structural strengthening is necessary when the structure’s load-bearing capacity is insufficient. In many cases, the two solutions can be integrated.