The Sanctuary of Vicoforte is dedicated to the Nativity of the Blessed Virgin Mary and is one of the great masterpieces of Piedmontese-baroque architecture. The basilica features the largest elliptical dome in the world and the fifth largest dome after St Peter’s in the Vatican, the Pantheon in Rome, the Cathedral of Santa Maria del Fiore in Florence and Gol Gumbaz in India.
The events leading to its construction date from the late 15th century and started with a votive shrine standing in a wood, now lost, at the foot of the Vicoforte hills. The first stone was laid in 1596 to an original design by Ascanio Vitozzi, an architect from Orvieto active in the Court of Savoy and engaged at the time in giving Turin the appearance of a “capital city”. Vitozzi proposed grandiose and monumental architecture for the Sanctuary. Inspired by the main buildings appearing in Rome in that period, it fully reflected the Mannerist taste of the late-16th and early-17th centuries. Vitozzi died in 1615, when construction had reached the level of the cornice on which the drum, the architectural feature at the base of the top dome, was supposed to rest. After the death of Duke Charles Emmanuel I in 1630, the political and financial backing that had been key to the work’s launch was also lost and work on the Sanctuary was halted for nearly 100 years. Building work was then restarted by Mondovì architect Francesco Gallo. Between 1701 and 1733, he corrected structural flaws in the part already completed by Vitozzi and designed and constructed the drum and great elliptical dome that tops the building. The wooden scaffolding erected for the works on the dome was dismantled with some apprehension on 20 May 1732. In the years that followed, Gallo continued to work on the Sanctuary to complete the interior spaces. Subsequent works executed in the 19th century focused on the facades and bell-towers, each project reflecting the taste and architectural styles of the moment. The four bell-towers were completed in or around 1880 and originally terminated in elaborate baroque spires, demolished for safety reasons in 1906. Around the same time, the pitched roof Francesco Gallo had designed to cover the dome was replaced with the present copper cladding.
The dome of the Sanctuary has a surface area of 6.000 square metres and is decorated with the largest single-themed fresco in the world. Based on the popular “theology in pictures” model, it depicts episodes from the life of the Virgin Mary and her Glorious Assumption. Francesco Gallo decided to leave the inner surface of the dome perfectly smooth to provide a large, continuous area for the painted decoration. This fairly unusual choice gives the painter the added task of imagining an “architectural” decoration around the figurative part of the fresco. In 1741 the famous architect and scenic painter Giuseppe Galli da Bibiena was asked to work on the large frescoed surface. He can be attributed with certain surviving perspective effects but his attempt also fell short of expectations. Mattia Bortoloni from Rovigo and Felice Biella from Milan actually completed the fresco between 1746 and 1748. The result is a light but luminous whole clearly inspired by the work of the Venetian artist Giambattista Tiepolo.
Erected in 1732, the Sanctuary was affected by differential settlements of the foundation since the beginning of its construction, due to the poor quality of the soil at the site. This led to several and significant structural problems to the drumdome system, exhibited by an extended network of cracks along the meridian directions. For this reason, the Italian Ministry of Cultural Heritage financed in 1975 some studies on the structure and the foundations (mainly focused in investigating the nature of the supporting soil), a topographic survey and investigations on the masonry and crack network. These analyses were performed by the company Rodio and the Engineers Bernasconi and Marchini, while Politecnico di Torino determined by experimental tests the physical and mechanical properties of the masonry. In 1985-87 a modern strengthening system consisting of 14 groups of tangential ties was applied, located in ducts drilled in the masonry. The force in the tie-bars may be regulated at any time by jacks and the stress is constantly monitored by load cells. No substantial increases in the crack widths were observed after the installation of the reinforcement system.
From its very origins – linked to what is considered a miraculous event – the Sanctuary was a major centre of worship and a key pilgrim destination, such that in the late 16th century Charles Emmanuel I Duke of Savoy decided that the basilica would house the tombs of the royal family. Only the Duke is buried in the Sanctuary of Vicoforte, however, and his heir chose the Basilica of Superga, designed by Filippo Juvarra, to house the Savoy Mausoleum. A Royal Decree dated 1880 awarded the Sanctuary of Vicoforte national monument status.
In 2015 , partly thanks to the tourist boost induced by Expo2015 in Milan , the Sanctuary’s cultural value has been enhanced and the dome exceptionally opened to the public. The path that allows visitors to reach the base of the roof lantern is unusual and rather adventurous: the 75 meters high climb provides aerial ways, winding staircases, chambers never open to the public and that were formerly reserved to the workforce. The project, called Magnificat2015, was conceived and designed by the social enterprise “Kalatà” , which operates in the field of Cultural Assets and Activities , combining creative insights and organizational skills. This secured climb to the dome has been made possible by direct Kalatà investment (300’000 €) and the Sanctuary of Vicoforte’s cooperation. The estimated number of visitors is 20'000 while 15 under-35s are working as stable employees for the whole event’s duration.
In order to make the tour safe, 250 metres of fall restraint system and anchor devices have been installed in the sanctuary. This safety equipment won’t be dismantled at the end of the project, it will facilitate maintenance works in the medium and long term.
Universidad Politécnica de Madrid – Politecnico di Torino
· Ventura G., Coppola M., Calderini C., Chiorino M.A. (2012). Three-Dimensional Limit Analysis of
the Vicoforte Elliptical Dome. In: INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE.
· Aoki T., Chiorino M. A., Roccati R. (2003). Structural characteristics of the elliptical masonry dome of the sanctuary of Vicoforte. In: PROCEEDINGS OF THE FIRST INTERNATIONAL CONGRESS ON CONSTRUCTION HISTORY, MADRID, 20TH-24TH JANUARY 2003.