Unique Aspects of Scaffolding Design for the Urgent Seismic Retrofitting of Zagreb Cathedral
Abstract
:1. Introduction
1.1. A Brief History of the Zagreb Cathedral
1.2. The Condition of the Cathedral after the 2020 Earthquakes
2. Urgent Seismic Retrofitting Design Concept
3. Scaffolding Structures
3.1. General
3.2. Internal Scaffolding
3.3. External Scaffolding
3.4. Tower Scaffolding
3.4.1. State of the Old Tower Scaffolding
3.4.2. The New Tower Scaffolding
- Phase I included the construction of the platform P1 at a height of +36.8 m to +42.0 m, which supports the new modular scaffolding, and the erection of the scaffolding to support the elevator from ground level (±0.0 m) to +39.2 m, together with an elevator and its substructure.
- Phase II comprised the erection of the new scaffolding from platform P1 (+42.0 m) to the current height of the towers (+96.2 m). During successive assembly, the scaffolding is horizontally braced to the towers up to a height +66.2 m.
- Phase III follows the reconstruction and strengthening of the cathedral towers. The scaffolding continues from the existing Phase II structure from +96.2 m to the top of the newly strengthened tower at +106.2 m, with horizontal braces being added to the towers every three levels from +74.2 m.
4. Conclusions
- By stabilising damaged parts of the cathedral and preventing further collapse, the scaffolding played a critical role in preserving the cathedral’s historical and cultural integrity.
- The scaffolding enabled detailed structural assessments and inspections, allowing engineers and restorers to identify and address specific areas of concern more effectively.
- Modular scaffolding allowed for faster and more efficient assembly and disassembly, crucial given the urgency of the restoration and retrofitting work. Despite lower geometric adaptability, precise planning using point cloud models allowed modular scaffolding to fit complex geometries. This approach is replicable in other projects requiring rapid deployment and high safety standards.
- Unique anchoring methods for attaching scaffolding to thick stone towers walls can be easily adapted and applied to similar restoration projects.
- For such complex structures, nonlinear analysis was crucial in predicting the real behaviour of the scaffolding and ensuring its stability and effectiveness. This analysis helped in understanding of real behaviour, that is, how the scaffolding would respond under various loads and stresses, particularly during wind actions.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
- Šimunić, I.; Šimunić-Buršić, M. Vault of the Sacristy of Zagreb Cathedral. Prost. Znan. Časopis Za Arhit. I Urban. 2015, 23, 344–353. (In Croatian) [Google Scholar]
- Foretić, D. Thirty Years of Renovation of Zagreb Cathedral. Klesar. I Graditelj. 2019, 29, 34–53. [Google Scholar]
- Šavor Novak, M.; Uroš, M.; Atalić, J.; Herak, M.; Demšić, M.; Baniček, M.; Lazarević, D.; Bijelić, N.; Crnogorac, M.; Todorić, M. Zagreb earthquake of 22 March 2020—Preliminary report on seismologic aspects and damage to buildings. Građevinar 2020, 72, 843–867. [Google Scholar]
- NN 75/2020: Tehnički Propis o Izmjeni i Dopunama Tehničkog Propisa za Građevinske Konstrukcije; Government of Croatia: Zagreb, Croatia, 2022; (In Croatian). Available online: https://narodne-novine.nn.hr/clanci/sluzbeni/2020_07_75_1448.html (accessed on 31 May 2024).
- Skejić, D.; Lukačević, I.; Ćurković, I.; Čudina, I. Application of steel in refurbishment of earthquake-prone buildings. Građevinar 2020, 72, 955–966. [Google Scholar]
- Zagrebačka Katedrala: Izvješće o Oštećenjima, Obavljenim Radovima i Planovima Obnove Zagrebačke Katedrale. (In Croatian). Available online: https://katedrala.hr/hr/izvjesce-o-ostecenjima-obavljenim-radovima-i-planovima-obnove-zagrebacke-katedrale/749 (accessed on 31 May 2024).
- Lazarević, D.; Gidak, P.; Šamec, E.; Jaguljnjak Lazarević, A.; Fresl, K. Seismic Analysis of Zagreb Cathedral—Current State. Struct. Anal. Hist. Constr. SAHC 2023, 1, 918–928. [Google Scholar]
- Šamec, E.; Gidak, P.; Jaguljnjak Lazarević, A.; Oreb, J. On the Selection of Distinct Element Method for Numerical Analysis of Zagreb Cathedral. In Proceedings of the 10th ICCSM International Congress of Croatian Society of Mechanics, Pula, Croatia, 28–30 September 2022. [Google Scholar]
- Gidak, P.; Šamec, E.; Fresl, K.; Lazarević, D. Geometry Generation and Modelling of Non-Standard Cross Vaults. In Proceedings of the IASS 2022 Symposium Affiliated with APCS 2022 Conference, Beijing, China, 19–22 September 2022. [Google Scholar]
- Romero-Sánchez, E.; Requena García de la Cruz, M.V.; Morales-Esteban, A. Seismic Assessment of Historic Complex Towers. The Case Study of the Giralda Tower. COMPDYN 2023. In Proceedings of the 9th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Athens, Greece, 12–14 June 2023; Papadrakakis, M., Fragiadakis, M., Eds.; pp. 5191–5201. [Google Scholar]
- Bayraktar, A.; Hökelekli, E.; Şermet, F.; Mosallam, A.S. A FRCM technique for strengthening of masonry domes against near-fault pulse-like vertical excitations. Eng. Fail. Anal. 2024, 163, 108478. [Google Scholar] [CrossRef]
- Requena García de la Cruz, M.V.; Romero-Sánchez, E.; Morales-Esteban, A.; Fernández-Pérez, N. A Model for the Structural and Seismic Assessment of the Mosque-Cathedral of Cordoba. COMPDYN 2023. In Proceedings of the 9th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Athens, Greece, 12–14 June 2023; Papadrakakis, M., Fragiadakis, M., Eds.; pp. 5179–5190. [Google Scholar]
- 3DEC 7.0 Documentation. Available online: http://docs.itascacg.com/3dec700/common/docproject/source/manual/program_guide/models/models.html (accessed on 3 October 2022).
- Cathedral of the Assumption of Mary. Geotechnical Study; Grasa projekt d.o.o.: Zagreb, Croatia, 2021. (In Croatian) [Google Scholar]
- Cathedral of the Assumption of Mary. Geophysical Survey Report; Geotehnički studio d.o.o.: Zagreb, Croatia, 2022. (In Croatian) [Google Scholar]
- Cathedral of the Assumption of Mary. Engineering Geological Investigation Report; Geotehnički studio d.o.o.: Zagreb, Croatia, 2022. (In Croatian) [Google Scholar]
- Cathedral of the Assumption of Mary. Seismological Investigation Report for the Location of the Cathedral of the Assumption of Mary, Archdiocese of Zagreb (Description of Seismicity and Earthquake Hazard Assessment at the Location of the Cathedral of the Assumption of Mary, Archdiocese of Zagreb); University of Zagreb, Faculty of Science, Department of Geophysics: Zagreb, Croatia, 2022. (In Croatian) [Google Scholar]
- Herak, M.; Herak, D.; Orlić, N. Properties of the Zagreb 22 March 2020 earthquake sequence—Analyses of the full year of after-shock recording. Geofizika 2021, 38, 1–26. [Google Scholar]
- Herak, M.; Herak, D.; Živčić, M. Which one of the three latest large earthquakes in Zagreb was the strongest–the 1905, 1906 or 2020 one. Geofizika 2021, 38, 1–33. [Google Scholar]
- EN 1998-1:2004+AC:2009; Eurocode 8: Design of Structures for Earthquake Resistance—Part 1: General Rules, Seismic Actions and Rules for Buildings. European Committee for Standardization (CEN): Brussels, Belgium, 2011.
- HRN EN 1998-1:2011/NA:2011/A1:2021; Eurocode 8: Design of Structures for Earthquake Resistance—Part 1: General Rules, Seismic Actions and Rules for Buildings—National Annex. Croatian Standards Institute: Zagreb, Croatia, 2021.
- EN 1998-3:2005+AC:2010; Eurocode 8: Design of Structures for Earthquake Resistance—Part 3: Assessment and Retrofitting of Buildings. European Committee for Standardization (CEN): Brussels, Belgium, 2011.
- kat.S130-18\17, AJ:112-223/02/2021; Cathedral of the Assumption of Mary, Preliminary Study on the Assessment of the Existing State of the Structure of the Cathedral. University of Zagreb, Faculty of Civil Engineering, Department of Engineering Mechanics: Zagreb, Croatia, 2022. (In Croatian)
- Nemetschek Scia. Scia Engineer; Nemetschek Group: Munich, Germany, 2020; Version 20.1. [Google Scholar]
- EN 12811-1:2003; Temporary Works Equipment—Part 1: Scaffolds-Performance Requirements and General Design. European Committee for Standardization (CEN): Brussels, Belgium, 2003.
- Allgemeine Bauaufsichtliche Zulassung Z-8.22-939, Ausgabe 10.2018, Deutsches Institut für Bautechnik—DIBt (In German). Available online: https://www.dibt.de/de/service/zulassungsdownload/detail/z-822-939 (accessed on 10 July 2024).
- EN 1991-1-4:2005+AC:2010+A1:2010; Eurocode 1: Action on Structures—Part 1-4: General Actions–Wind Actions. European Committee for Standardization (CEN): Brussels, Belgium, 2010.
- kat.S130-18\6, MK-DS-07/21; Cathedral of the Assumption of Mary, Urgent Main Design of Load-Bearing Steel Scaffolding on the West Side of the Cathedral. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2021. (In Croatian)
- EN 1991-1-3:2003+A1:2015; Eurocode 1: Action on Structures—Part 1-3: General Actions-Snow Load. European Committee for Standardization (CEN): Brussels, Belgium, 2015.
- prEN 1991-1-9:202x; Eurocode 1: Action on structures—Part 1-9 Atmospheric Icing-Final Draft. European Committee for Standardization CEN/TC 250/SC1: Brussels, Belgium, 2020.
- kat.S130-18\15, MK-DS-01/22; Cathedral of the Assumption of Mary, Urgent Main Design of Load-Bearing Steel Scaffolding for Internal Support and Securing the Damaged Structure of the Cathedral. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2022. (In Croatian)
- kat.S130-18\15, MK-DS-02/22; Cathedral of the Assumption of Mary, Urgent Detailed Design of Load-Bearing Steel Scaffolding for Internal Support and Securing the Damaged Structure of the Cathedral. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2022. (In Croatian)
- EN 12812:2008; Falsework–Performance Requirements and General Design. European Committee for Standardization (CEN): Brussels, Belgium, 2008.
- kat.S130-18\19, MK-DS-04/22; Cathedral of the Assumption of Mary, Urgent Main Design of Load-Bearing Steel Scaffolding for External Support of Structural and Non-Structural Parts of the Cathedral and Scaffolding for Urgent Renovation Works. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2022. (In Croatian)
- kat.S130-18\19, MK-DS-05/22; Cathedral of the Assumption of Mary, Urgent Detailed Design of Load-Bearing Steel Scaffolding for External Support of Structural and Non-Structural Parts of the Cathedral and Scaffolding for Urgent Renovation Works. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2022. (In Croatian)
- kat.S130-18\5, MK-DS-03/21; Cathedral of the Assumption of Mary, Urgent Main Design for the Rehabilitation/Removal of the Existing Steel Scaffolding and the South Tower Platform. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2021. (In Croatian)
- kat.S130-18\5, MK-DS-05/21; Cathedral of the Assumption of Mary, Urgent Detailed Design for the Rehabilitation/Removal of the Existing Steel Scaffolding and the South Tower Platform. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2021. (In Croatian)
- EN 14399-1:2015; High Strength Structural Bolting Assemblies for Preloading—Part 1: General Requirements. European Committee for Standardization (CEN): Brussels, Belgium, 2015.
- kat.S130-18\6, MK-DS-08/21; Cathedral of the Assumption of Mary, Urgent Detailed Design of Load-Bearing Steel Scaffolding on the West Side of the Cathedral. University of Zagreb, Faculty of Civil Engineering, Department of Structures, Chair for Metal Structures: Zagreb, Croatia, 2022.
Parameter | Scaffolding Type | |
---|---|---|
Tubular Scaffolding | Modular Scaffolding | |
Geometric adaptability | High, they can be customised to almost any shape and size of object | Lower, predefined configurations |
Assembly time | Can be lengthy | Faster assembly |
Cost | Variable, depends on the project | Higher initial cost, but may be more cost-effective for reuse |
Standardisation | Low, each scaffolding is unique | High, standardised members |
Storage | Requires more space due to the irregular components | Requires less space due to the uniformity of the members |
Safety | Potentially less safety through inconsistent assembly | Higher safety standards through better integration of components |
Durability | Variable, usually only primer coating applied | High, all members are hot-dip galvanized |
Load-carrying capacity | Lower in most cases | Greater, eccentricities in the nodes are smaller |
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Skejić, D.; Čudina, I.; Valčić, A.; Lazarević, D. Unique Aspects of Scaffolding Design for the Urgent Seismic Retrofitting of Zagreb Cathedral. Buildings 2024, 14, 2167. https://doi.org/10.3390/buildings14072167
Skejić D, Čudina I, Valčić A, Lazarević D. Unique Aspects of Scaffolding Design for the Urgent Seismic Retrofitting of Zagreb Cathedral. Buildings. 2024; 14(7):2167. https://doi.org/10.3390/buildings14072167
Chicago/Turabian StyleSkejić, Davor, Ivan Čudina, Anđelo Valčić, and Damir Lazarević. 2024. "Unique Aspects of Scaffolding Design for the Urgent Seismic Retrofitting of Zagreb Cathedral" Buildings 14, no. 7: 2167. https://doi.org/10.3390/buildings14072167