Concrete structures and infrastructure facilities represent strategic components for the welfare of communities and the development of society. The effects of aging and deterioration processes, as reported by several recent catastrophic events strongly affect the performance of concrete structures and infrastructure facilities. The thesis deals with the structural response at the ultimate limit state of reinforced concrete (RC) and prestressed concrete (PC) beams under the effects of corrosion and uncertainties. Within this context, the long-standing challenge of understanding the shear response of concrete beams, investigated for over a century, is contributed by conducting a thorough review and comparison of the methods proposed in literature and code provisions for the ultimate strength assessment of RC/PC beams. In particular, the predictive capabilities and limitations of several methodologies are investigated through a large database of experimental results collected from literature for RC/PC beams tested under shear. Moreover, the results of experimental campaigns available in the literature associated with RC beams under corrosion are adopted to investigate the ability of the existing methods to accommodate reinforcing steel corrosion effects. Uncertainties associated with material mechanical properties and the exposure scenario are accounted for based on probabilistic methods and implemented by means of numerical Monte Carlo simulation to assess the life-cycle structural capacity of RC beams subjected to chloride-induced corrosion. The effectiveness of the shear strength assessment methods is also investigated through a wide experimental campaign developed within the BRIDGE|50 research project that aims to analyze the residual performance of a 50-year-old dismantled PC bridge in Italy (bridge50.org). The results highlight the importance of accounting for the effects of deterioration and uncertainties in the life-cycle assessment of RC structures associated with a transition in the hierarchy of flexural-shear failure mechanism.
Le strutture e infrastrutture in calcestruzzo rappresentano una componente strategica per il benessere delle comunità e lo sviluppo della società. Gli effetti dei processi di invecchiamento e degrado, come evidenziato da diversi recenti eventi catastrofici, influenzano fortemente le prestazioni delle strutture e infrastrutture in calcestruzzo. La tesi riguarda la risposta strutturale allo stato limite ultimo di travi in calcestruzzo armato (CA) e calcestruzzo armato precompresso (CAP) considerando gli effetti della corrosione e delle incertezze. In questo contesto, si vuole dare un contributo alla sfida posta dalla comprensione della risposta a taglio delle travi in calcestruzzo, oggetto di studio per oltre un secolo, attraverso una approfondita revisione bibliografica e un confronto dei metodi proposti in letteratura e delle prescrizioni normative per la valutazione della resistenza ultima di travi in CA/CAP. In particolare, le capacità predittive e i limiti delle diverse metodologie sono stati analizzati attraverso un ampio database di risultati sperimentali raccolti in letteratura per travi in CA/CAP provate sperimentalmente a taglio. Inoltre, sono stati adottati i risultati di campagne sperimentali disponibili in letteratura associate a travi in CA sottoposte a corrosione per studiare la capacità dei metodi esistenti di considerare gli effetti della corrosione dell'acciaio ordinario. Le incertezze associate alle proprietà meccaniche dei materiali e allo scenario di esposizione sono state considerate sulla base di metodi probabilistici e implementate mediante simulazioni Monte Carlo per valutare la capacità strutturale a ciclo di vita di travi in CA sottoposte a corrosione indotta da cloruri. L'efficacia dei metodi di valutazione della resistenza al taglio viene inoltre indagata attraverso un'ampia campagna sperimentale sviluppata nell'ambito del progetto di ricerca BRIDGE|50, che mira ad analizzare le prestazioni residue di un ponte in CAP smantellato dopo una vita utile di circa 50 anni (bridge50.org). I risultati evidenziano l'importanza di considerare gli effetti del degrado e delle incertezze nella valutazione a ciclo di vita delle strutture in CA associati ad una transizione nella gerarchia dei meccanismi di rottura a flessione e taglio.
Validation of shear strength prediction models of corrosion-damaged concrete beams
Agrawal, Anjali
2022/2023
Abstract
Concrete structures and infrastructure facilities represent strategic components for the welfare of communities and the development of society. The effects of aging and deterioration processes, as reported by several recent catastrophic events strongly affect the performance of concrete structures and infrastructure facilities. The thesis deals with the structural response at the ultimate limit state of reinforced concrete (RC) and prestressed concrete (PC) beams under the effects of corrosion and uncertainties. Within this context, the long-standing challenge of understanding the shear response of concrete beams, investigated for over a century, is contributed by conducting a thorough review and comparison of the methods proposed in literature and code provisions for the ultimate strength assessment of RC/PC beams. In particular, the predictive capabilities and limitations of several methodologies are investigated through a large database of experimental results collected from literature for RC/PC beams tested under shear. Moreover, the results of experimental campaigns available in the literature associated with RC beams under corrosion are adopted to investigate the ability of the existing methods to accommodate reinforcing steel corrosion effects. Uncertainties associated with material mechanical properties and the exposure scenario are accounted for based on probabilistic methods and implemented by means of numerical Monte Carlo simulation to assess the life-cycle structural capacity of RC beams subjected to chloride-induced corrosion. The effectiveness of the shear strength assessment methods is also investigated through a wide experimental campaign developed within the BRIDGE|50 research project that aims to analyze the residual performance of a 50-year-old dismantled PC bridge in Italy (bridge50.org). The results highlight the importance of accounting for the effects of deterioration and uncertainties in the life-cycle assessment of RC structures associated with a transition in the hierarchy of flexural-shear failure mechanism.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/219622