From Realtà Mapei International n° 74 - 09/05/2019

Sanctuary of the Madonna dell’Ambro, Montefortino (Italy)

Following the earthquake in 2016, the Sanctuary underwent delicate restoration and seismic upgrading work before being handed back to visitors and worshippers on the 21st of December last year.

Mapei took part in the work by supplying products and the support of a team of engineers and technicians with experience in the field of structural strengthening.

Solutions with FRP, FRCM and CRM technology were employed for the interventions, selecting materials designed specifically for structural strengthening work and also by adopting solutions suitable for treating frescoes and decorative antique surfaces.

Location icon Montefortino

A CENTURIES-OLD STORY

Situated in the Monti Sibillini National Park, the Sanctuary of the Madonna dell’Ambro is the most ancient place of worship dedicated to the Madonna in the Marche Region (Central Italy). At the beginning of the 11th century a small church, the Church of Santa Maria in Amaro, was built in the place where the Madonna had made an appearance and was entrusted to Benedictine monks from the nearby Santi Vincenzo and Anastasio monastery. At the beginning of the 17th century, under the jurisdiction of the diocese of Fermo, it was decided to construct a larger church. The work was designed by the architect Ventura Venturi from the Santa Casa di Loreto, who was commissioned to design a church that incorporated the original Church of Santa Maria in Amaro and 6 lateral chapels alongside the aisle of the church.

 

THE EARTHQUAKE THAT CHANGED EVERYTHING

Following the earthquake that struck the area on the 24th of August, 2016, the structure was badly damaged with serious cracks that compromised its general stability.

Montefortino City Council made the Sanctuary safe by implementing a project by Luigino Dezi, a professor in Construction Technology at the Polytechnic University of Marche, and the engineer Massimo Conti.

 

THE CONSERVATIVE RESTORATION AND SEISMIC UPGRADING PROJECT

The work on the structure included consolidation of the brick vaulted ceiling over the aisle; the insertion of 510 steel chains with 36 mm diameter around the main arches; the construction of a system of kerbs and tie-rods along the top of the roof, partly in breccia rock on the 1.5 m thick walls to avoid creating too much transversal stiffness, and partly in reinforced masonry; the positioning of steel bars in the openings of the upper altar wall and of an embedded tie-rod to counteract out-of-plane loads; consolidation of the lateral chapels and the walls of the upper tombs; stitching of the dividing walls in the chapels; positioning of a band of carbon fibre to prevent the apse from collapsing; the insertion of dywidag anchor bars to prevent the tympanum of the main facade collapsing; the insertion of chains around the belfry and in the filler material used to stitch various cracks.

 

 

PARTNERS IN THE RECONSTRUCTION AND THE PROJECT

The sponsor of the initiative, the Cassa di Risparmio di Fermo bank, asked for Mapei’s collaboration to carry out the work and Mapei, as Technical Partner for the project, supplied experts from the company’s Technical Services Department and various cutting-edge product systems.

Consolidation of the vaulted ceiling was carried out in two  phases.

Firstly, the damaged areas were repaired with a product chosen for its compatibility with the existing mortar’s mechanical properties and level of porosity, its resistance to physical and chemical aggression (freeze-thaw cycles) acting on the ceiling and its compatibility with the frescoed surfaces. A product suitable for repairing frescoed surfaces was chosen so that, during its application, the substrate would not need to be wetted and, while it was setting, it would not give off free lime that would have caused the formation of efflorescence and potentially damage the decorated surface.

The ceiling was then consolidated by applying on the outer face a composite system with an inorganic matrix. All the products used contained no cement, as specified by the local Heritage Board. For the upper part of the apse, a composite system with an organic matrix was proposed, which consisted of carbon fibre fabric and epoxy resin to guarantee a constraint on mechanisms out-of-plane of the macro-element.

 

 

VAULTS, WALLS AND APSE: THE SOLUTIONS FROM MAPEI

COMPOSITE MESH AND CEMENT-FREE MORTARS AND BINDERS FOR THE ANCIENT MASONRY AND TO SAFEGUARD THE FRESCOES

To consolidate the outer face of the existing vaulted roofs PLANITOP HDM RESTAURO was used, a product made of an inorganic matrix of natural hydraulic lime and Eco-Pozzolan. This product, which was applied in an even layer using a flat, metal trowel, allows to smooth and level off masonry surfaces such as stone, brickwork and tuff.

When applied in combination with MAPEGRID B 250 alkali-resistant basalt fibre mesh, as in this case, it is used to strengthen the structure of masonry buildings.

To ensure the strengthening of the side walls, MAPEWRAP B FIOCCO high-strength basalt fibre cords were prepared and then bonded in place with MAPEFIX EP 470 SEISMIC pure epoxy resin-based chemical anchor for structural loads.

MAPE-ANTIQUE F21 salt-resistant, 100% cement-free hydraulic binder made from lime and Eco-Pozzolan was poured into the frescoed vaulted ceilings.

To strengthen the masonry, it was rendered with MAPE-ANTIQUE STRUTTURALE NHL high-performance mortar made of hydraulic lime and Eco-Pozzolan, reinforced with MAPENET EM40 alkali-resistant glass fibre mesh and L-shaped MAPENET EM CONNECTOR fasteners made from alkali-resistant glass fibre and thermosetting vinylester-epoxy resin.



FRP SYSTEM TO FORM STRENGTHENING BANDS AROUND THE APSE

In the apse area a number of bands were applied using a typical FRP SYSTEM, which included the application of MAPEWRAP C UNI-AX 600 unidirectional, high modulus, high-strength carbon fibre fabric, MAPEWRAP PRIMER 1 epoxy primer, MAPEWRAP 11 epoxy grout to level off surfaces and for bonding, MAPEWRAP 31 medium viscosity epoxy adhesive to impregnate and bond the fabric and MAPEWRAPP C FIOCCO high-strength carbon fibre cord to form structural ties.

The FRP bands were then protected by covering them with a layer of MAPE-ANTIQUE ECOLASTIC cement-free, lime and Eco-Pozzolan-based, waterproof elastic coating, which is used to protect construction features and elements, including those of historical and artistic interest.

 

Project data sheet

Yard masonry vaults
Location Montefortino, Italy
Subcategory CHURCH
Application supply of products for masonry restoration and strengthening
Start and finish date 2018
Application Type Masonry restoration, Structural reinforcement
Client CASSA DI RISPARMIO DI FERMO
Contractor company AR ALESSANDRINI Nello srl
Installer companies AR ALESSANDRINI Nello srl
Architects Ing. Diego Damen - Arch. Giulia Alessandrini
Designers (for works) Ing. Diego Damen - Arch. Giulia Alessandrini
MAPEI Coordination ZAFFARONI - DE CARLI - CARBOTTI - CONSORTI - PETTI
Other Consulente progettazione strutturale Prof. Ing. Luigino Dezi

Products mentioned in the article

MAPEWRAP C UNI-AX SYSTEM
MAPEWRAP C UNI-AX SYSTEM
STRUCTURAL STRENGTHENING SYSTEM CONSISTING OF HIGH-STRENGTH HIGH-MODULUS UNIDIRECTIONAL CARBON FIBRE FABRIC AND EPOXY RESINS TO IMPREGNATE...
PLANITOP HDM RESTAURO
PLANITOP HDM RESTAURO
Two-component, pre-blended, high-ductility, fibre-reinforced, hydraulic lime (NHL) and ECO-POZZOLAN-based light-coloured mortar,...
MAPEGRID B250
MAPEGRID B250
Alkali-resistant, primed basalt-fibre mesh for structural “reinforced” strengthening of stone masonry, brick, tuff and concrete surfaces....
MAPEWRAP B FIOCCO
MAPEWRAP B FIOCCO
Unidirectional high strength basalt fibre cord to be impregnated with MAPEWRAP 21 (two-component super-fluid epoxy resin) to make...
MAPEFIX EP 470 SEISMIC
MAPEFIX EP 470 SEISMIC
Pure epoxy resin-based chemical anchor for structural loads. Certified for threaded bar, construction bars, and C2 seismic loads. TECHNICAL...
MAPE-ANTIQUE F21
MAPE-ANTIQUE F21
Super-fluid, salt-resistant, hydraulic binder with fillers made from lime and ECO-POZZOLAN applied by injection for consolidating masonry...
MAPE-ANTIQUE STRUTTURALE NHL
MAPE-ANTIQUE STRUTTURALE NHL
High-performance breathable mortar for render and masonry work made from natural hydraulic lime and ECO-POZZOLAN, particularly suitable for...
MAPENET EM40
MAPENET EM40
Pre-impregnated alkali-resistant A.R. glass fibre mesh (FRP) used to make “reinforced” structural render on concrete and masonry...
MAPEWRAP PRIMER 1
MAPEWRAP PRIMER 1
Two-component epoxy primer specifically formulated for the MAPEWRAP system. TECHNICAL DATA: Mixing ratio: comp. A : comp. B = 3 : 1....
MAPEWRAP 31
MAPEWRAP 31
Two-component, medium-viscosity epoxy adhesive for impregnating MAPEWRAP using the “dry system”. TECHNICAL DATA: Mixing ratio: comp. A :...
MAPEWRAP 11
MAPEWRAP 11
Two-component, normal-setting, thixotropic epoxy grout for evening out concrete surfaces and for structural bonding. TECHNICAL DATA: Mixing...
MAPEWRAP C FIOCCO
MAPEWRAP C FIOCCO
High-strength carbon fibre cord to be impregnated with MAPEWRAP 21 (two-component, super-fluid epoxy resin) to make “structural...
MAPE-ANTIQUE ECOLASTIC
MAPE-ANTIQUE ECOLASTIC
Two-component, elastic, salt-resistant, cement-free, lime and Eco-pozzolan based coating for waterproofing and protecting construction...
Realtà Mapei Tags: #support #repair #strengthening

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