This thesis examines approaches and strategies for the classification, risk management, and safety assessment of the Italian infrastructure system. To this end, on the one hand, the New Italian Guidelines (LLGG) issued by the Ministry of Infrastructure and Transport (MIT) in 2020 were analysed, and on the other hand, a case study concerning a reinforced concrete (RC) bridge from the 1950s scheduled for demolition was examined. The research is grounded in continuous comparison and reference to real-world case studies, both at a territorial scale and at the level of individual assets. For the former, reference was made to a stock of approximately 650 structures involved in a national pilot study coordinated by the ReLUIS Consortium, aimed at monitoring the initial phase of implementation of the LLGG by motorway operators and certain local authorities. In the first part of the study, the LLGG text was analysed to highlight critical issues and propose modifications, with a focus on structural-foundation and seismic risks. Particular attention was given to Level 0 of the multi-level process introduced by the LLGG, through an analysis of data collected in the ReLUIS pilot project forms. This analysis revealed both systemic issues and others linked to the “discretion” of the operators. A proposal for a standardized nomenclature and a specific descriptive manual was developed to mitigate these issues. The proposed improvements yielded promising results when applied to the collected data. The analysis then focused on the parameters most influencing the Risk Class (“Classe di Attenzione” in the guidelines - CdA), identified through an in-depth study of the logical processes underlying the LLGG. These parameters include the level of defectiveness and traffic-related metrics. The study revealed that some of these parameters are difficult to determine precisely and are therefore conservatively estimated by the operator. This tends to "homogenize" the structures by assigning them to higher levels of CdA. To support this, traffic data available in the literature were analysed and compared to corresponding values assigned to structures in the ReLUIS study. A preliminary application of these findings was conducted for the case study. Further analysis of the LLGG focused on the verification levels. In particular, for Level 3, both procedural considerations and proposed modifications to the verification report were developed, incorporating effects related to self-weight and material degradation. All these aspects were also verified and implemented in the case study presented in the second part of the thesis. This concerns the bridge over the Fratta River in Valli Mocenighe (Province of Padua), a typical RC bridge from the 1950s representative of a widely used structural typology in Italy. The study, conducted in collaboration with the Province of Padua and the University of Bologna, included an initial detailed assessment of the structure, the development of a controlled demolition plan to extract four beams for laboratory testing, and a numerical-experimental analysis to design the four-point bending test setup to be conducted at the CIRI laboratory of the University of Bologna. The test setup design was supported by phase-based numerical analyses. A preliminary phase used analytical models and considerations on reinforcement layouts to determine the optimal configuration of loading forces to avoid shear failure. The subsequent phase, through nonlinear static analysis on a finite element model of the beam, allowed for validation of the test setup and evaluation of the maximum expected forces, displacements, and rotations during testing. In both phases, Monte Carlo simulations were conducted to assess the impact of uncertainties in material mechanical properties on the beam response.
Questa tesi prende in esame approcci e strategie per la classificazione, gestione del rischio e valutazione di sicurezza del sistema infrastrutturale italiano. A tal fine, da un lato si sono analizzate le Linee Guida (LLGG) emanate dal MIT nel 2020 e, dall'altro, si è esaminato un caso studio riguardante un ponte in c.a. risalente agli anni ‘50 destinato alla demolizione. La ricerca si basa su un confronto e riferimento continuo con casi studio reali, sia su scala territoriale, che su singoli casi studio. Per la prima si è fatto riferimento ad uno stock di circa 650 opere oggetto di sperimentazione nazionale, a cui si è partecipato sotto il coordinamento del Consorzio ReLUIS, al fine di monitorare la prima fase di applicazione delle LLGG da parte di gestori autostradali ed enti locali. Nella prima parte si è analizzato il testo delle LLGG evidenziando alcune criticità ed elaborando alcune proposte di modifica concentrandosi sui rischi strutturale-fondazionale e sismico. Si è approfondito in particolare il Livello 0 del processo multilivello introdotto dalle LLGG, analizzando i dati raccolti nelle schede relative alle opere in sperimentazione ReLUIS. Da questa analisi emergono sia criticità sistemiche che altre legate alla “discrezionalità” dell’operatore. Si è quindi elaborata una proposta di nomenclatura condivisa, con uno specifico manuale descrittivo, al fine di ridurre tali problematiche. Ottimi risultati sono stati osservati dall’analisi dei dati raccolti a seguito dell’applicazione delle proposte. L’analisi si è poi focalizzata sui parametri che più influenzano la Classe di Attenzione (CdA) individuati mediante studio approfondito dei processi logici che stanno alla base delle LLGG. Tra questi vi sono il livello di difettosità e i parametri di traffico. Dallo studio svolto è emerso che alcuni di questi risultano difficili da conoscere e vengono quindi assunti in modo cautelativo dal gestore. Questo tende ad “omogenizzare” le opere livellandole nei livelli più alti di CdA. A supporto si sono svolte analisi sulle misurazioni di traffico disponibili in letteratura confrontandole con i corrispondenti valori espressi per le opere in sperimentazione ReLUIS. Una prima applicazione di tali risultati è stata condotta per il caso studio. Proseguendo l’analisi delle LLGG la tesi approfondisce i livelli di verifica. In particolare, per il Livello 3, si sono fatte considerazioni procedurali e proposte di modifica al rapporto di verifica integrandolo con gli effetti legati al peso proprio e il degrado. Tutti questi aspetti sono stati verificati e implementati anche nel caso studio presentato nella seconda parte della tesi. Si tratta del ponte sul fiume Fratta a Valli Mocenighe (PD), un ponte in c.a. ordinario risalente agli anni '50, rappresentativo di una tipologia strutturale molto diffusa in Italia. Lo studio, in collaborazione con la Provincia di PD e l'Università di Bologna, ha previsto un approfondimento iniziale sull’opera, lo sviluppo di un piano per la demolizione controllata per estrarre quattro travi da testare in laboratorio e un'analisi numerico-sperimentale per progettare il setup delle prove di flessione a quattro punti che saranno effettuate presso il laboratorio CIRI dell’UniBO. La progettazione del setup di prova è avvenuta con il supporto di analisi numeriche articolate per fasi. Una preliminare ha consentito, mediante modelli analitici e considerazioni sul layout delle armature, di valutare la configurazione ottimale delle forze da applicare per evitare rotture a taglio. La fase successiva, mediante analisi statiche non lineari sul modello ad elementi finiti della trave, ha permesso di validare il setup di prova e valutare l’entità massima di forze, spostamenti e rotazioni in gioco durante la prova. In entrambe le fasi si sono svolte analisi Monte Carlo per valutare il ruolo delle incertezze delle proprietà meccaniche dei materiali sulla risposta delle travi.
La Fragilità del Sistema Infrastrutturale Italiano: Approcci e Strategie per la Classificazione, Gestione del Rischio e Valutazione di Sicurezza dei Ponti Esistenti / Bottin, Gianluca. - (2025 May 06).
La Fragilità del Sistema Infrastrutturale Italiano: Approcci e Strategie per la Classificazione, Gestione del Rischio e Valutazione di Sicurezza dei Ponti Esistenti
BOTTIN, GIANLUCA
2025-05-06
Abstract
This thesis examines approaches and strategies for the classification, risk management, and safety assessment of the Italian infrastructure system. To this end, on the one hand, the New Italian Guidelines (LLGG) issued by the Ministry of Infrastructure and Transport (MIT) in 2020 were analysed, and on the other hand, a case study concerning a reinforced concrete (RC) bridge from the 1950s scheduled for demolition was examined. The research is grounded in continuous comparison and reference to real-world case studies, both at a territorial scale and at the level of individual assets. For the former, reference was made to a stock of approximately 650 structures involved in a national pilot study coordinated by the ReLUIS Consortium, aimed at monitoring the initial phase of implementation of the LLGG by motorway operators and certain local authorities. In the first part of the study, the LLGG text was analysed to highlight critical issues and propose modifications, with a focus on structural-foundation and seismic risks. Particular attention was given to Level 0 of the multi-level process introduced by the LLGG, through an analysis of data collected in the ReLUIS pilot project forms. This analysis revealed both systemic issues and others linked to the “discretion” of the operators. A proposal for a standardized nomenclature and a specific descriptive manual was developed to mitigate these issues. The proposed improvements yielded promising results when applied to the collected data. The analysis then focused on the parameters most influencing the Risk Class (“Classe di Attenzione” in the guidelines - CdA), identified through an in-depth study of the logical processes underlying the LLGG. These parameters include the level of defectiveness and traffic-related metrics. The study revealed that some of these parameters are difficult to determine precisely and are therefore conservatively estimated by the operator. This tends to "homogenize" the structures by assigning them to higher levels of CdA. To support this, traffic data available in the literature were analysed and compared to corresponding values assigned to structures in the ReLUIS study. A preliminary application of these findings was conducted for the case study. Further analysis of the LLGG focused on the verification levels. In particular, for Level 3, both procedural considerations and proposed modifications to the verification report were developed, incorporating effects related to self-weight and material degradation. All these aspects were also verified and implemented in the case study presented in the second part of the thesis. This concerns the bridge over the Fratta River in Valli Mocenighe (Province of Padua), a typical RC bridge from the 1950s representative of a widely used structural typology in Italy. The study, conducted in collaboration with the Province of Padua and the University of Bologna, included an initial detailed assessment of the structure, the development of a controlled demolition plan to extract four beams for laboratory testing, and a numerical-experimental analysis to design the four-point bending test setup to be conducted at the CIRI laboratory of the University of Bologna. The test setup design was supported by phase-based numerical analyses. A preliminary phase used analytical models and considerations on reinforcement layouts to determine the optimal configuration of loading forces to avoid shear failure. The subsequent phase, through nonlinear static analysis on a finite element model of the beam, allowed for validation of the test setup and evaluation of the maximum expected forces, displacements, and rotations during testing. In both phases, Monte Carlo simulations were conducted to assess the impact of uncertainties in material mechanical properties on the beam response.File | Dimensione | Formato | |
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3-2025-04-24-Bottin Gianluca-Tesi PhD-Elaborato Finale_archivio.pdf
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Descrizione: La Fragilità del Sistema Infrastrutturale Italiano: Approcci e Strategie per la Classificazione, Gestione del Rischio e Valutazione di Sicurezza dei Ponti Esistenti
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