Freyssinet stabilises foundations, consolidates and strengthens masonry structures, while minimising operations that might harm the authenticity of the historic elements. Precise monitoring and a diagnosis are required to identify the areas to treat and define their criticality.

  • Masonry bridges
  • Stone buildings
  • Heritage structures
  • Stone-built retaining walls

Main challenges

Stone buildings can change shape, fracture and develop cracks as a result of bearing settlement, shell buckling, arch thrust forces or a simple loss of cohesion in the masonry of pointing between stonework. There are also problems of insufficient strength of structures under the modified loads. Whatever the cause of the problem, it usually manifests itself in decompression, or even the masonry placed under tensile load or excessive shear.

The success of good waterproofing is an essential factor in the durability of masonry structures. The effects of water are harmful for several reasons, in particular by the penetration into the joints with disintegration of the mortar then the dislocation of the masonry and the action of the freeze-thaw cycles with deterioration of the stonework, desquamation or surface disruption (cyclic action of atmospheric agents, etc.), appearance of blackish spots, invasion by vegetation, local disappearance or stripping of joints and sometimes appearance of significant damage.

The ageing of stones used in masonry can accentuate their original defects, including lamination, inclusions, original cracks and porosity.

Arched masonry structures are sensitive to settlement and deformation. It is therefore necessary to pay attention to the deformation of the arch, either linked to the settlements of the bearings, or during the work (deformation of the ring beam, settlement on decentring) or during the life of the structure (effects of operating loads, temperature and delayed deformations). Too much flexibility would also risk causing problems to the masonry.

The increase in the forces supported by the bridges requires an evaluation and strengthening project. In particular:

  • Increase in permanent load by reprofiling the carriageway
  • Increase in traffic overload. This increase is added to an additional aggressiveness linked to vibrations and dynamic effects.

Increase in the rolling width by eliminating footpaths and consequently, vehicles travelling too close to the spandrels create a greater horizontal thrust, therefore risk of major damage.

The absence of a minimum of maintenance can generate, in the medium term, a gradual deterioration of the masonry structure. This can involve, for example, the growth of harmful vegetation on the structure because this maintains a permanent humidity of the masonry, but also because the proliferation of roots is likely to displace stones and to gradually disrupt masonry.

Masonry structures

A complete range of services

Protective measures

Freyssinet supports its clients right from the strengthening project preparation phase and designs made-to-measure solutions in conjunction with the architect and/or design firms in charge of the renovation.

Assistance with diagnosis

Before proceeding with a repair and/or strengthening, carrying out a precise survey is essential to determine the cause(s) of the damage, delimit the areas to be treated and define their criticality. Specific solutions are required as each structure is unique. Each time, an in-depth analysis of the problems is carried out in order to propose suitable strengthening or repair solutions.

Engineering analysis of the structure

The existing state of the structure and the nature of the loads are essential data for the design and calculation of masonry structures.

Freyssinet is available to assist contractors and design firms in the analysis and calculation of the structure.

Assistance in defining the consolidation strategy

Freyssinet has developed a range of specific products to strengthen and repair masonry structures. These products are based on technical specifications established by Freyssinet’s technical department. These specifications are validated regularly by an inspection agency.

Execution of strengthening work

Repairing a structure requires careful planning and safe execution, in order to manage risks, meet deadlines and ensure the safety of users and operators. Freyssinet’s strength lies in its strict adherence to a quality charter at every stage of its work and in its dedicated repair teams, from the analysis of existing problems to their repair. This approach guarantees our clients the effectiveness and durability of the solutions adopted.

Our range of solutions

Underpinning

The objective of micropile underpinning is to take up the structural forces on the deep soil layers through inclusion in the form of lateral friction, mobilised along the shaft, with a high bearing capacity and less risk of settlement. This technique is widely used for the repair of existing foundations, and for the reinforcement of the foundations of existing structures, as the drilling equipment for micropiles is small and lightweight and allows working inside the existing structure.
  • Load transfer
  • Accessibility in difficult areas

Foreva Stone Tie rod

This solution improves the mechanical behaviour of the masonry, which then behaves as a reinforced element with a stress zone consisting of a compressed stone upper part and a tensioned reinforcement in the lower part. Wherever possible, the internal reinforcing bars are positioned to follow the tensile stress lines. They are sealed in their slots with a resin or grout which, after curing or setting, transfers the loads between the masonry and the reinforcing bar along its length. The tie rods are then loaded when the structure changes shape. For arches, tie bars are used for major longitudinal fractures in the body of the arch, or fractures or delamination of the headwalls (panels, spandrels) of the arch.
  • Discreet solution
  • Guaranteed durability
  • Seaming of cracks
    in a uniform manner

Foreva Stone TFC

Structural stone elements can be strengthened by bonding a carbon fibre composite reinforcement element. The Foreva® Pierre TFC solution uses strips of carbon fibre fabric in a Foreva® Epx TFC epoxy resin, which bonds them to the masonry. The Foreva® WFC 100M carbon fibre braid anchoring process can be used to additionally seal the composite reinforcement element into the masonry. The strength of stone sections reinforced with bonded composite is substantiated as stated in Freyssinet's technical specifications. Carbon fibre fabric reinforced composites are an ideal means of strengthening elements with deformed surfaces and subjected to tensile or bending loads.
  • Lightweight and discreet solution
  • Durability
  • Quick installation

Foreva Stone Inertia Sup

Resin concrete upstands can be used to increase the stress area of the girders and to enhance rigidity. The Foreva® Stone Inertia Sup solution uses a compression flange strengthened with Foreva® Epx B963 resin concrete, attached to the element being strengthened by glass fibre rods. The strength of stone sections strengthened with a mounted compression flange is substantiated as set out in Freyssinet's technical specifications.
  • Better load distribution on the original structure
  • Increasing moment of inertia
  • Ideal for listed ceilings

Foreva Stone Active tie rods

Pre-stressed tie rods can be used to compress masonry. As the loads introduced into the structure are moderate, a single reinforcing bar is usually sufficient. They can be internal or external to the elements they strengthen. The Foreva® Pierre Tirant Actif solution normally uses a very low-relaxation prestressing strand that is factory sheathed to provide effective corrosion protection. They have the advantage of resisting any attempt at displacement at the very moment it tends to occur.
  • Guaranteed loading
  • Excellent durability
  • Discreet solution

Dry shotcrete

Dry shotcreting is a technique for strengthening the concrete under the initial arch, usually to a thickness of between 8 and 20 cm. It is highly recommended, as it ensures good adhesion to the substrate. High strengths can be easily achieved with this process, which allows low water/binder ratios to be obtained.
  • Adhesion monolithism
  • Extrados strengthening for structures in service
  • Increasing moment of inertia

Moving and sliding of heavy loads

Heavy handling and sliding techniques enable historic structures to be moved while keeping them in perfect condition.
  • Town planning integration
  • PIntegration of urban constraints

Underpinning

The objective of micropile underpinning is to take up the structural forces on the deep soil layers through inclusion in the form of lateral friction, mobilised along the shaft, with a high bearing capacity and less risk of settlement. This technique is widely used for the repair of existing foundations, and for the reinforcement of the foundations of existing structures, as the drilling equipment for micropiles is small and lightweight and allows working inside the existing structure.
  • Load transfer
  • Accessibility in difficult areas

Foreva Stone Tie rod

This solution improves the mechanical behaviour of the masonry, which then behaves as a reinforced element with a stress zone consisting of a compressed stone upper part and a tensioned reinforcement in the lower part. Wherever possible, the internal reinforcing bars are positioned to follow the tensile stress lines. They are sealed in their slots with a resin or grout which, after curing or setting, transfers the loads between the masonry and the reinforcing bar along its length. The tie rods are then loaded when the structure changes shape. For arches, tie bars are used for major longitudinal fractures in the body of the arch, or fractures or delamination of the headwalls (panels, spandrels) of the arch.
  • Discreet solution
  • Guaranteed durability
  • Seaming of cracks
    in a uniform manner

Foreva Stone TFC

Structural stone elements can be strengthened by bonding a carbon fibre composite reinforcement element. The Foreva® Pierre TFC solution uses strips of carbon fibre fabric in a Foreva® Epx TFC epoxy resin, which bonds them to the masonry. The Foreva® WFC 100M carbon fibre braid anchoring process can be used to additionally seal the composite reinforcement element into the masonry. The strength of stone sections reinforced with bonded composite is substantiated as stated in Freyssinet's technical specifications. Carbon fibre fabric reinforced composites are an ideal means of strengthening elements with deformed surfaces and subjected to tensile or bending loads.
  • Lightweight and discreet solution
  • Durability
  • Quick installation

Foreva Stone Inertia Sup

Resin concrete upstands can be used to increase the stress area of the girders and to enhance rigidity. The Foreva® Stone Inertia Sup solution uses a compression flange strengthened with Foreva® Epx B963 resin concrete, attached to the element being strengthened by glass fibre rods. The strength of stone sections strengthened with a mounted compression flange is substantiated as set out in Freyssinet's technical specifications.
  • Better load distribution on the original structure
  • Increasing moment of inertia
  • Ideal for listed ceilings

Foreva Stone Active tie rods

Pre-stressed tie rods can be used to compress masonry. As the loads introduced into the structure are moderate, a single reinforcing bar is usually sufficient. They can be internal or external to the elements they strengthen. The Foreva® Pierre Tirant Actif solution normally uses a very low-relaxation prestressing strand that is factory sheathed to provide effective corrosion protection. They have the advantage of resisting any attempt at displacement at the very moment it tends to occur.
  • Guaranteed loading
  • Excellent durability
  • Discreet solution

Dry shotcrete

Dry shotcreting is a technique for strengthening the concrete under the initial arch, usually to a thickness of between 8 and 20 cm. It is highly recommended, as it ensures good adhesion to the substrate. High strengths can be easily achieved with this process, which allows low water/binder ratios to be obtained.
  • Adhesion monolithism
  • Extrados strengthening for structures in service
  • Increasing moment of inertia

Moving and sliding of heavy loads

Heavy handling and sliding techniques enable historic structures to be moved while keeping them in perfect condition.
  • Town planning integration
  • PIntegration of urban constraints

Download our brochure

Documentation
Documentation

Discover our references

Repair
France

Elbeuf church

Part of the old plaster vaults of a Norman church was reinforced using resin concrete and carbon fiber fabrics bonded on both sides of the vault by carbon braids.
Discover more
Repair
Madagascar

Sahasinaka masonry structure strengthening

Featuring a combined concrete and masonry structure, the Sahasinaka viaduct was built in 1934. As one of the pier foundations showed signs of subsidence, structural strengthening of the bridge was conducted by Freyssinet.
Discover more

Learn more about our other solutions

Repair

Heritage structures
Repair

Structural strengthening
Repair

Seismic retrofitting
Repair

Structural integrity management
Repair

Heritage structures
Repair

Structural strengthening
Repair

Seismic retrofitting
Repair

Structural integrity management

You have a project?

Our local experts will help you achieve your project thanks to our large range of solutions.
Find your local contact

You have a project?

Our local experts will help you achieve your project thanks to our large range of solutions.
Find your local contact