The importance of cognitive investigations and surveys in Restoration work: the Project of the Church of San Pietro ad Montes, province of Caserta

Cognitive investigations and surveys are essential tools in restoration work, as they provide a detailed understanding of the state of conservation of a building or structure. Cognitive surveys, through the analysis of materials, construction techniques and any modifications undergone over time, provide vital information for planning interventions that respect the building’s authenticity and history.

The importance of surveys, however, lies in several aspects:

1. Thorough knowledge of the current state: Surveys allow the collection of accurate data regarding the physical characteristics of structures, including size, shape, materials, and condition of preservation. This knowledge is crucial for proper assessment of the state of preservation and for identifying any damage or degradation.

2. Intervention planning: Accurate surveys provide a basis for planning interventions for restoration, renovation, or structural improvement. They allow problems to be identified and targeted solutions to be proposed that respect the integrity of the structure and its history.

3. Preservation of cultural heritage: In historic buildings or buildings of cultural significance, surveying becomes an essential tool for documenting the original layout and preserving a detailed record of the changes that have been made over time. This helps to maintain the authenticity of structures while complying with preservation regulations.

4. Risk prevention: Structural surveys, which also include load, deformation, and stress analyses, are critical in identifying potential risk situations. A good understanding of the structure helps prevent subsidence or other issues that could compromise safety.

5. Enhancement of existing resources: Gathering information through surveys also allows for the enhancement and reuse of existing buildings and structures. In-depth knowledge enables the design of interventions that not only improve safety but also the aesthetics and functionality of the building, reducing the consumption of new resources and promoting sustainability.

Surveys and investigations provide the necessary basis for respectful and safe intervention, allowing the building to be returned to the community in its full splendor, while preserving its historical integrity.

The Benedictine Abbey of San Pietro ad Montes is located in Caserta, in the hamlet of Piedimonte di Casolla, on the slopes of Mount Virgo.

The Abbey has a rectangular plan and is divided into three naves separated by twelve columns. Adjacent to the abbey is a mighty bell tower, in ruins, with a square plan. The subject building was declared a national monument in 1895.

The analysis of the state of affairs and the design of the interventions concerned only the Abbey and did not include the neighboring portions that make up the complex.

Brief historical notes

The Abbey “Monasterio Sancti Petri”, located at the foot of the Caserta Mountains, is first mentioned in 1139 in a donation by Nicola Frainella, abbot of San’Amasio di Aprino, lord of Caserta. Subsequently, it was mentioned in various documents, including privileges granted by the Counts of Caserta and papal privileges, up to and including the papal tithes of 1308-1310. The Benedictine community inhabited the abbey until 1435, when it was granted in “commenda” to Tommaso Latro, a member of a noble Caserta family. After several periods of decline, it was entrusted to the fathers of the Congregation of Christian Doctrine in 1730 and later recognized as a royal patronage in 1795. In 1866, the convent was suppressed and became part of the state property. After damage caused by World War II, the building was restored and used by the Oblate Sisters of the Sacred Heart until 1990. Over the years, the abbey suffered various damages, including the collapse of a vertical septum due to bombing, and received numerous restoration works, including re-roofing and structural consolidation. The most recent restoration work, which began in the 1990s, included consolidation of the structures and damage restoration, with detailed documentation of the state of deterioration and the interventions carried out

Description of the state of affairs

The church has three naves, separated by twelve granite and porphyry columns with Ionic, Corinthian, and composite capitals probably from Roman buildings, supporting round arches. Both columns and capitals are likely from Roman buildings. The naves end without a transept and with blind apses, once frescoed, set against the limestone rock.

The facade, in gray and yellow tuff, is hidden by a courtyard erected in the 18th century, with a flight of steps and a five-bay portico.

The internal structure follows the early Christian scheme, but without a transept, with seven arches on each side connecting the nave to the side aisles, and three semicircular apses, the central one larger.

Structurally, the building consists of masonry made of regular tuff blocks and columns, topped by composite Ionic and Corinthian capitals, made of granite and porphyry. As for the roofing, this is composed of exposed wooden trusses, planking and a covering finishing system; along the perimeter of the nave and the two side aisles, at the eaves level, there is a reinforced concrete curb with a height of about 30cm.

Laser Scanner Survey

A laser scanner survey for masonry structures is an advanced technique used to acquire high-precision three-dimensional data. This type of survey was used to conduct the survey of the Benedictine Abbey of San Pietro ad Montes.

The process employs a 3-D laser scanner, which is an instrument that emits a series of laser pulses toward the surface to be surveyed, recording the return times of each pulse to construct a point cloud representative of the surface geometry. Once acquired, the data are transferred into processing software to create the 3-D model. After processing, we move on to the graphical restitution stage, where the point cloud is transformed into a three-dimensional model. This model can be used for visual representation to create sections, floor plans or three-dimensional views of the building.

Cognitive investigations – the endoscopic investigations

In the field of restoration, endoscopic investigations are among the most important because of their ability to explore inaccessible and difficult-to-see areas without damaging the structure. Using non-invasive techniques, such as endoscopy, it is in fact possible to examine inside walls, floors, attics or foundations, gathering valuable information on the state of materials, the presence of cavities, moisture or internal damage. This type of investigation provides a direct and detailed view of structural conditions, without the need for excavation or demolition, thus reducing the risks of damaging the building and respecting its integrity. Endoscopic investigations are particularly effective for detecting hidden issues, such as the deterioration of concrete or wooden structures, the presence of mold or fungal infections, and for monitoring the quality of repairs or materials used in previous interventions, thus obtaining crucial data for designing targeted and safe restoration interventions.

In the case of the Benedictine Abbey of San Pietro ad Montes, endoscopic investigations were carried out in the holes of the micro-carvings using an ANYKIT NTS 300 Endoscope.

The endoscopies made it possible to detect inside the masonry intensely fractured limestone blocks and presence of voids and cavities.

Proposal for static restoration and seismic consolidation work

The intervention’s project was designed consistently with the Theories, Principles and Charters of Restoration, adopting as a general reference the criteria proper to conservative restoration, pursuing the dual purpose of restoring the original unity to the monumental building and improving its response to the earthquake, adopting minimal, appropriate, compatible, reversible, distinguishable and cost-benefit conscious interventions.

From the analysis of the actual state of the Abbey, thanks to the survey and cognitive investigations conducted, rehabilitation and restoration interventions were planned and grouped into three macro areas:

I. Structural and consolidation works;

II. Functional/architectural interventions;

III. Restoration works.

Structural consolidation works

From the structural and consolidation point of view, the main works planned were:

– the intervention of chaining the arcades of the portico;

– the intervention of scuci e cuci of the masonry;

– the consolidation of subfoundation of the colonnades;

– the hooping intervention of the columns;

– the consolidation intervention of the arches.

Functional/architectural interventions

In order to increase the durability of the materials and the periodicity of routine maintenance of the complex, the following restoration, refurbishment and/or re-functionalization works have been planned:

– Maintenance work on the roof by remaking the waterproofing system and protective treatment of the wooden surfaces;

– Reconstruction of the vaulted surfaces of the porch;

– Re-plastering of the exterior and interior non-frescoed facades;

– Maintenance work on the porch roof by redoing the waterproofing system;

– Cleaning of rock-floored surfaces by low-pressure pressure washer and anti-mold treatment;

– Cleaning of terracotta paved surfaces by low-pressure pressure washer and subsequent polishing;

– Renovation of outdoor channels by laying suitable waterproofing surfaces and cleaning adjacent green areas.

Restoration

Regarding the restoration works of the frescoes, considering the diagnostic results, work is carried out in accordance with the usual restoration techniques, namely surface veiling, consolidation of plaster of frescoes and pictorial decorations, consolidation of the pictorial film of frescoes and pictorial decorations, cleaning of frescoes and pictorial decorations, removal of unsuitable plastering, grouting of frescoes and pictorial decorations, pictorial integration, and final protection of frescoes.

 

STANDARDS AND BIBLIOGRAPHY

[1] M. Infrastrutture Trasporti 17/01/2018 (G.U. 20/02/2018 n. 42 – Suppl. Ord. n. 8)“Aggiornamento delle Norme tecniche per le Costruzioni”.

[2] Circolare 21 gennaio 2019, n. 7 C.S.LL.PP. (G.U. Serie Generale n. 35 del 11/02/2019 – Suppl. Ord. n. 5) Istruzioni per l’applicazione dell’«Aggiornamento delle “Norme tecniche per le costruzioni”» di cui al decreto ministeriale 17 gennaio 2018.

[3] Linee Guida per la valutazione e riduzione del rischio sismico del patrimonio culturale allineate alle nuove Norme tecniche per le costruzioni.