Structural assessment and conservation of modern built heritage

The temporal proximity of the heritage of the twentieth century, especially the one made of reinforced concrete, has delayed a shared attention to the conservation issues that it manifests. The awareness of the historical, architectural and cultural values of the ‘recent’ architectural heritage, combined with the serious and growing problems of structural safety, today fuels a greater sensitivity to this heritage, making it worthy of protection as a tangible evidence of a particular historical moment, rich in discoveries and experiments on new materials (ICOMOS 20C).

In particular, twentieth-century concrete architectural heritage is closely tied to conceptual design principles focused on the authenticity of material use and construction methods. It is well understood that heritage structures whose significance is closely associated to exposed concrete components require particular attention to ensure durability and aging aspects are carefully accounted for and managed. The conservation process for such heritage assets relies on multidisciplinary expertise and encompasses several phases, with detailed condition assessments playing a pivotal role. Structural analysis and characterisation represent crucial features of this assessment. 

The sructural analysis and health monitoring (SHM) of a valuable structure of the twentieth century cultural heritage, the Flaminio Stadium in Rome, is addressed. The Flaminio is one of the iconic reinforced concrete sport facilities designed and built by Pier Luigi Nervi for the 1960 Olympic Games of Rome. In view of the foreseen SHM activity, the structural analysis of the Flaminio Stadium is firstly reported by presenting either preliminary analyses, aimed at studying the stadium response under different modeling hypotheses, and a three-dimensional Finite Element (FE) model of the entire structure. It turns out that the main grandstand canopy plays a pivotal role in the Flaminio’s structural response to seismic excitation; in addition, its state of conservation raises some concern. Therefore, the structural modeling and dynamic characterization of the canopy is deepened in the paper. Its unusual features, such as geometry, material characteristics and dynamic interplay with the hosting main reinforced concrete frames are thoroughly assessed. To validate the FE results, characterized by a high modal density, and investigate the response of the structure, dynamic tests carried out under operating conditions are presented. The output-only collected data are used to calibrate the initial FE model. The predicted static and dynamic responses of the canopy are eventually exploited to guide the design of a tailored monitoring system. The relevant data management is framed in a heritage building information modeling (HBIM) context. This study draws a viable process for a proactive structural conservation strategy of twentieth-century heritage buildings and infrastructures [3,4].

The historical analysis of the structural features of Carlo Mollino’s Teatro Regio, built in Turin in the early 70s, gives evidence of peculiar technical and expressive solutions worth being studied. In addition to the well-known “special structures,” conceived by Sergio Musmeci, Teatro Regio includes a magnificent example of reinforced concrete doubly curved shell used for the lyric hall’s large-span roof. The roof was designed and built by Felice Bertone, an Italian engineer who devoted his activity to daring reinforced concrete design. In this study, the original theatre configuration is redrawn, modeled, and discussed based on archival documentation. This unique hypar thin shell concrete roof is thoroughly described focusing on its intertwined geometric and static features. Bertone’s roofing parametric modeling is eventually presented including a critical interpretation of its structural behavior carried out through qualitative and quantitative analysis. The Teatro Regio architecture with its innovative forms and structural solutions represents an outstanding example of Modern Heritage Architecture [5].

[1] Zagaroli A., Romeo F., Bernardini D., Fiber-Based Modeling and Analysis of Deteriorated Reinforced Concrete Heritage Structures: The Case Study of “Palazzetto dello Sport” by Pier Luigi Nervi, Lecture Notes in Civil Engineering, 326 LNCE, pp. 257–266, 2023.

[2] Ciambella J., Romeo F., Ranzi G.,  Dynamic characterization of a modern heritage structure: the Palazzetto dello Sport by Pier Luigi Nervi, Proceedings of Eurodyn 2023, July 3-5, TU Delft.

[3] Di Re P., Lofrano E., Ciambella J., Romeo F. , Structural analysis and health monitoring of twentieth-century cultural heritage: The Flaminio Stadium in Rome, Smart Structures and Systems, 27(2), pp. 285–303, 2021.

[4] Diacodimitri A., Giodice M., Romeo F., Balsi M., Developing Critical Knowledge of Twentieth-Century Cultural Heritage via Massive Survey: The Case of the Conservation Plan of the Stadio Flaminio in Rome, Springer Tracts in Civil Engineering, pp. 1291–1317, 2022.

[5[ Romeo F., Carughi U., Margiotta Nervi E., Rossi P.O., Vittorini R., The Stadio Flaminio in Rome by Pier Luigi and Antonio Nervi: an interdisciplinary conservation plan, Technical Report from grant for the conservation of 20th century architecture (Keeping It Modern Report Library), Getty Foundation conservation plans repository, 2020.

[6] Ricordi J., Romeo F., The hyperbolic paraboloid roof of the Teatro Regio in Turin by Felice Bertone, International Journal of Space Structures, 38(4), pp. 284–301, 2023.

[7] Lembo, M., Bologna, A., Romeo, F., Nervi’s Isostatic Lines’ Inspired Floor Slabs. Beyond the Archetypal Gatti Woolen Mill in Rome, Lecture Notes in Civil Engineering, 437, pp. 51–61, 2024.