The numerous seismic phenomena that occurred in Italy in recent years have highlighted the need to preserve the national building heritage and have boosted the search for innovative and effective technological solutions for anti-seismic retrofitting of existing buildings. In this context, research into fiber reinforced cementitious matrix (FRCM) composites has recently resulted in guidelines defining their use and features. The objective of the present dissertation is the study of the behavior of some of the various possible solutions of glass-fiber mesh and cementitious matrix or lime which form the composite. To this end, an experimental testing campaign was carried out resulting in the choice of a single type of composite, also through numerical models, to define the necessary parameters for a case study. The case study – specifically chosen in load-bearing masonry as this represents the main solution in the Italian building scenario – was evaluated for its seismic vulnerability through an equivalent frame model, according to the current NTC2018 regulation. The subsequent analysis, with the addition of the reinforcement, made it possible to evaluate the effects of FRCM. The building involved is the maternity ward of the former hospital in Lecco, which was abandoned for years and later given to Politecnico di Milano to be requalified and incorporated into the university campus in Lecco, which will happen within next year. Besides the structural reinforcement project of the ward there is also a proposal for architectural refurbishment, alternative to the one being implemented. The design of the intervention was preceded by the overview of the context in which the lot was inserted, and a cognitive survey of its actual state as to geometry, materials and technology was carried out. The project involves the inclusion of services for the city and the Campus, as well as an intervention that is both non-invasive – as the building is protected by the Superintendence – and recognizable for the architectural solutions adopted. Therefore, an added storey is proposed to be used as exhibition hall, with a reticular roof in fiber-reinforced concrete, whose translucent coating makes it recognizable in the city landscape. This solution aims at referring to the works of Pierluigi Nervi regarding its intended use, including the exhibition of study models of works. The selected technological, plant-engineering and energetic strategies have been subjected to relevant tests in order to guarantee efficiency and regulatory accordance of the building recovery project.
I numerosi fenomeni sismici avvenuti in Italia negli ultimi anni hanno messo in evidenza la necessità di salvaguardare il patrimonio edilizio nazionale e hanno incentivato la ricerca di soluzioni tecnologiche innovative ed efficaci per il rinforzo antisismico delle costruzioni esistenti. In tale contesto si inserisce la ricerca sui compositi fibrorinforzati a matrice inorganica (FRCM) sui quali sono state pubblicate solo di recente delle linee guida che ne definiscano le modalità di impiego e la caratterizzazione. L’obiettivo di questa tesi è lo studio del comportamento di alcune delle numerose soluzioni possibili di rete in fibra di vetro e matrice a base cementizia o di calce che formano il composito. A tale scopo è stata effettuata una campagna di prove sperimentali al termine delle quali è stata scelta una sola tipologia di composito, approfondita attraverso la realizzazione di modelli numerici con i quali sono stati definiti i parametri necessari per l’applicazione ad un caso studio. Di quest’ultimo, scelto appositamente in muratura portante in quanto soluzione predominante nel panorama degli immobili italiani, è stata svolta in fase preliminare la verifica della vulnerabilità sismica della sua struttura attraverso un modello a telaio equivalente, con riferimento alle normative vigenti NTC 2018. La successiva analisi con aggiunta del rinforzo ha permesso di valutare gli effetti del FRCM stesso. L’edificio è l’ex Padiglione maternità appartenente al vecchio complesso ospedaliero di Lecco, abbandonato per anni e successivamente dato in concessione al Politecnico di Milano con l’obbiettivo di rifunzionalizzarlo e inglobarlo nel Polo universitario di Lecco, come avverrà entro il prossimo anno. Al progetto di rinforzo strutturale del padiglione si affianca una proposta di recupero architettonico, alternativa a quella in fase di attuazione. Precede l’ideazione dell’intervento una fase di inquadramento del contesto in cui si inserisce il lotto e un’indagine conoscitiva dello stato di fatto con cui si definiscono la geometria, i materiali con il relativo stato di conservazione e la tecnologia. Il progetto prevede l’inserimento di servizi a disposizione per la città e per il Campus e un intervento che risulti, da un lato, poco invasivo essendo uno stabile sottoposto a tutela dalla Soprintendenza e, dall’altro, riconoscibile per le soluzioni architettoniche adottate. Si propone, quindi, il sopralzo di un piano adibito a sala espositiva con una copertura reticolare in calcestruzzo fibrorinforzato il cui rivestimento traslucido ne enfatizza la visibilità nel panorama cittadino. L’intento di tale soluzione è il richiamo alle opere di Pierluigi Nervi in relazione al carattere delle attività a cui è adibita, fra cui l’esposizione di modelli di studio delle sue opere. Le strategie tecnologiche, impiantistiche ed energetiche selezionate sono state sottoposte alle relative verifiche in modo da garantire l’efficienza e l’adeguatezza a livello normativo del progetto di recupero dell’edificio.
Impiego di compositi FRCM per il retrofitting antisismico di edifici in muratura. Applicazione al progetto di recupero dell'ex padiglione maternità dell'ospedale di Lecco
BESTETTI, FRANCESCO;MATTIOLO, GIORGIO MARCO
2017/2018
Abstract
The numerous seismic phenomena that occurred in Italy in recent years have highlighted the need to preserve the national building heritage and have boosted the search for innovative and effective technological solutions for anti-seismic retrofitting of existing buildings. In this context, research into fiber reinforced cementitious matrix (FRCM) composites has recently resulted in guidelines defining their use and features. The objective of the present dissertation is the study of the behavior of some of the various possible solutions of glass-fiber mesh and cementitious matrix or lime which form the composite. To this end, an experimental testing campaign was carried out resulting in the choice of a single type of composite, also through numerical models, to define the necessary parameters for a case study. The case study – specifically chosen in load-bearing masonry as this represents the main solution in the Italian building scenario – was evaluated for its seismic vulnerability through an equivalent frame model, according to the current NTC2018 regulation. The subsequent analysis, with the addition of the reinforcement, made it possible to evaluate the effects of FRCM. The building involved is the maternity ward of the former hospital in Lecco, which was abandoned for years and later given to Politecnico di Milano to be requalified and incorporated into the university campus in Lecco, which will happen within next year. Besides the structural reinforcement project of the ward there is also a proposal for architectural refurbishment, alternative to the one being implemented. The design of the intervention was preceded by the overview of the context in which the lot was inserted, and a cognitive survey of its actual state as to geometry, materials and technology was carried out. The project involves the inclusion of services for the city and the Campus, as well as an intervention that is both non-invasive – as the building is protected by the Superintendence – and recognizable for the architectural solutions adopted. Therefore, an added storey is proposed to be used as exhibition hall, with a reticular roof in fiber-reinforced concrete, whose translucent coating makes it recognizable in the city landscape. This solution aims at referring to the works of Pierluigi Nervi regarding its intended use, including the exhibition of study models of works. The selected technological, plant-engineering and energetic strategies have been subjected to relevant tests in order to guarantee efficiency and regulatory accordance of the building recovery project.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/143850