Pregledni rad
https://doi.org/10.17018/portal.2025.1
Activities of the Conservation Service in Implementing Protective Measures for the Zagreb Cathedral after the 2020 Earthquakes
Maja Gorianc Čumbrek
; Grad Zagreb, Gradski zavod za zaštitu spomenika kulture i prirode Odjel za provedbu državnih programa zaštite nepokretne kulturne baštine
Andrijana Tadić
; Grad Zagreb, Gradski zavod za zaštitu spomenika kulture i prirode Odjel za pokretnu i nematerijalnu kulturnu baštinu
Sažetak
The paper discusses the damage to the cathedral of the Assumption of the Blessed Virgin Mary and Saints Stephen and Ladislaus caused by the Zagreb earthquake on 22 March 2020, and the Petrinja earthquake on 29 December 2020. It also highlights the actions and activities of the conservation service in implementing protective measures after the earthquakes when dealing with the cathedral’s architecture and inventory. Initial assessments were conducted shortly after the earthquakes, revealing significant damage to the top of the north bell tower. Conservators of the City Institute for Cultural and Natural Heritage Conservation documented the damage using a form based on a Decision on the implementation of the inventory of damage to immovable cultural assets caused by the earthquake in Zagreb issued by the Minister of Culture and Media, Nina Obuljen Koržinek, on 10 April 2020. During the earthquake, the upper section of the south bell tower, about 10 metres high, collapsed, and similar damage was observed on the north bell tower at the same height. Numerous decorative stone elements fell from the façade, and cracks were detected between stone blocks on the exterior walls. The sanctuary’s stained-glass windows suffered significant damage. The ribbed vaults in the cathedral were heavily affected, particularly in the apse and west bays. Due to the damage, the cathedral has been closed to the public ever since.
After the City Institute decided on which protective measures were necessary that outlined procedures from a conservation perspective, the damaged top of the north bell tower was removed. This complex operation, conducted by an interdisciplinary team, was completed on 17 April 2020. Subsequent steps included installing external and internal scaffolding to support the vaults, drafting project specifications, and selecting designers for the restoration project. This was part of the grant programme for the implementation of protective measures for cultural heritage damaged in the earthquake on 22 March 2020, and funded by the EU Solidarity Fund. The selected consortium included the Faculty of Civil Engineering at the University of Zagreb and companies Toding, Studio Arhing, and Foretić & sinovi.
During the first inspection on 6 April 2020, it was observed that the movable inventory had not suffered significant damage apart from contamination from falling plaster. No major damage was initially evident on altars or other furnishings, so forms for listing damage to movable cultural property were not filled out. However, urgent protective measures required a more detailed expert inspection to determine further steps and the potential need for temporary evacuation of certain parts of the inventory. Minor damage, such as that to the angel statue on the pulpit, was identified later.
Following inspections by the Croatian Conservation Institute, the most vulnerable parts of the inventory were urgently evacuated from the sanctuary and organ prospect to the chapel of Blessed Augustin Kažotić in the cathedral’s north tower.
During emergency protective measures, an exceptional archaeological find was made: four fragments of a redmarble tombstone of former Zagreb Bishop Luka Baratin, who served from 1500 to 1510.
Given the cathedral’s architectural and construction characteristics (a monumental structure with 108-metre towers and ribbed vaults), its inherited structural deficiencies, and the unknowns about its condition during the earthquake due to the complexity of the project task within the deadlines, it was decided to prioritize designing and executing emergency repairs on the most severely damaged structural elements. While the Preliminary Study was prepared in order to assess the condition of the structure, extensive research was conducted to determine the exact composition and condition of the structure, along with properties of the underlying soil and foundations to assess the mechanical resistance and stability of the building as precisely as possible.
The preliminary structural study identified critical structural parts with respect to horizontal seismic forces: the tops of the bell towers above 73 metres, the bell tower between 36.75 and 55.85 metres, ribbed vaults in the nave with significant cracks, especially in the apse, inadequate existing braces and an insufficient number of them. The City Institute provided guidelines for further development of the project, and the need was confirmed for a conservation report, which was entrusted to the Croatian Conservation Institute.
In December 2021, a detailed inspection of the entire movable inventory in the cathedral complex was carried out, which resulted in the development of detailed guidelines by the City Institute on the further handling of these valuable items.
On 25 March 2022, the City Institute issued a preventive protection order for the inventory.
By mid-2022, seven emergency projects had been developed, including the Structural Assessment Study, Master Project and Detailed Design with cost estimates for emergency procedures, such as the removal of the damaged top parts of the bell towers, renovation of the bell towers between the first and second galleries, buttress repairs, ribbed-vault reinforcements, removal of damaged stone elements from the façade, dismantling the stained-glass windows in the sanctuary, and roof repairs. Projects for the construction of scaffolding were also developed. The text provides a description of interventions covered by the projects, and the special protection conditions that the City Institute established for individual interventions.
Emergency projects began in August 2022, with scaffolding installed throughout the interior, façade and towers. Renovation and dismantling of individual parts of the cathedral began in early 2023 with the selection of a contractor with continuous conservation oversight by the City Institute.
After obtaining prior approval, protective measures for movable inventory, including dismantling, relocation and temporary storage of part of the inventory, and in situ protection of the remaining movable inventory, began in November 2022. The above-mentioned work was carried out by the company IG visokogradnja with restoration instructions from the Croatian Conservation Institute and the conservation supervision of the City Institute. After the inventory was packaged, it was transported to the storage of the Croatian Conservation Institute in Ludbreg on 8 November 2022. Items remaining on-site, such as altars, choir stalls, bishop’s chair, railings, candelabra, and other fixtures, were encased in wooden protective coverings during construction.
Throughout November, all parts of the inventory that were to remain in situ were enclosed in wooden coverings and remained in the cathedral during all construction work.
In an expert opinion in September 2022, the City Institute confirmed the need to protect the cathedral organ in situ by encasing it in wooden protective coverings. The protection of the cathedral organ was carried out in March 2023 in accordance with guidelines from organologists, conservators and restorers, and work on the restoration of the cathedral vaults could begin.
At the time of writing, a significant portion of the work has been carried out in accordance with the approved project documentation, including the necessary elaboration of execution details after detailed inspections of the structure from scaffolding. Damaged stone elements, which posed a risk of falling, have been dismantled, stained glass windows from the sanctuary removed and stored, buttresses injected, vaults repaired and reinforced using an FRCM system, and new braces installed in all the bays.
Following the installation of scaffolding on the bell towers, complex work was undertaken to dismantle the stone elements of the top sections above the 85-m level, for which a steel conical structure was first installed inside the octagonal pyramidal lattice of the top section of the bell tower. All stone elements were documented and marked after dismantling. Continuous monitoring revealed damage to parts of the bell tower above the 73-m level, requiring the removal of elements at significantly greater heights than initially planned.
In the coming period, the development of a comprehensive structural restoration project and the continuation of work are expected.
Ključne riječi
City of Zagreb; City Institute for Cultural and Natural Heritage Conservation; immovable cultural property; movable cultural property; cathedral; earthquake; damage assessment; emergency protection measures
Hrčak ID:
341846
URI
Datum izdavanja:
15.12.2025.
Posjeta: 465 *