HISTORICAL METAL ROOFS AND BRIDGES
The main scope of the research is to develop a methodology for the assessment of the vulnerability and the use of reversible mixed technologies, with regard to historical and monumental metallic constructions. In particular, the main subject of the research is represented by the large span roofing structures and by ancient bridge, and retrofitting intervention with FRP. In order to acquire a full knowledge on the construction criteria and techniques of historic metal constructions, the first part of the programme involves a broad literature and bibliographic review. In case of the historic metal railway bridges, the case studies was selected in order to the strong collaboration established between the research unit and the Italian rail operator Ferrovie dello Stato, thus the case study selected is represented by the railway truss bridge on Gesso river, near Foggia. In case of large span roofing, the research is focused on the study of the Umberto I Gallery in Naples, which represents one of the tallest XIX century roofing structures made of iron and glass in Europe. Starting from a systematic analysis of archival and bibliographic sources, necessary to define the design criteria of the time, the research program has been articulated through a wide experimental activity, in order to characterize both the mechanical properties of historical material and the structural behavior of riveted connections. At this end, several tests for the identification of the ancient material on specimens sampled from the Dome and axial tests on specimens of different typology of riveted connections have been carried out. The investigations were carried out at the Laboratories of the Structural Engineering Department and Department of Constructions and Mathematical Methods in Architecture of the University of Naples “Federico II”. In order to analyze the structural vulnerability and the seismic capacity of the Dome and the bridge, three-dimensional finite element models have been implemented, by means of it both static and time history over accelerograms analyses have been carried out. These analyses have highlighted the structural deficiencies of the structures. In order to guarantee the structural integrity of the constructions, the research is ongoing in a strengthening solution using FRP. Although less attention has been dedicated to the use of FRP for the reinforcement of metallic elements, there are many advantages in favour of apply of this kind of retrofitting technique. Respect to traditional techniques, in fact, the use of FRP provides a remarkable increase of strength but not additional weight and mass. Moreover, the low weight of composite materials implies a consistent reduction of costs related to transportation, assembly and handling, the latter a very important aspect in the case of the Dome. In addition, FRPs are not affected by corrosion phenomena, and the bonding with epoxy resins consents to easily replace the material without injuring the support, with the complete respect of the historical and architectonical characteristics of the structures.
- “Vulnerabilità e tecniche di consolidamento reversibili per le strutture storiche in carpenteria metallica” Research Project of National Interest (PRIN): “Salvaguardia e riabilitazione strutturale di edifici storici mediante tecniche miste reversibili “, 2005-2007.
- “Metodologie di analisi per la previsione della risposta strutturale di manufatti architettonici in carpenteria metallica”, Research Project CNR: “Metodi e modelli predittivi del comportamento strutturale di manufatti in presenza e in assenza di danno”, 2002-2005.