Comprehensive assessment and management of deteriorating reinforced concrete bridges: advancing experimental exploration and enhancing evaluation methodologies for key components and the structural system

The global infrastructural heritage is currently facing an escalating risk due to the deterioration of bridge structures and the increased demographic and economic growth, which result in higher vehicular traffic demand on these structures. This scenario is largely a procedures and in-depth studies on deterioration phenomena causing structural weakening, such as the corrosion of steel reinforcement bars in concrete structures, identified as the primary cause of deterioration and risk. Nowadays, the topic of the assessment of corroded concrete structures is indeed pivotal in the field of civil engineering, and numerous studies have been conducted in recent decades. However, analyzing the literature, gaps have been identified regarding the assessment of the structural behavior of some critical components of concrete bridges. The structural behavior of Gerber half-joints, bridge deck connection components, remains poorly understood due to the lack of experimental evidence that considers, in particular, deterioration. Therefore, producing experimental results on the nonlinear behavior of these components in relation to different design and deterioration scenarios would enable the production of scientific evidence useful for the development of both analytical and numerical assessment methodologies and would also facilitate the development of targeted reinforcement strategies based on specific deterioration scenarios. Numerous studies have explored the effects of strand corrosion relative to beams and, particularly, corroded prestressed concrete beams. However, the real and continuous loading and deterioration conditions that these structures undergo in the real world often differ from the experimentally adopted testing methodologies. It is, therefore, crucial to analyze how new testing methodologies that better resemble these real conditions affect the characteristics of corrosion deterioration and, consequently, how these impact the structural behavior. Regarding assessment methodologies, both analytical and numerical, a wide range of methods proposed in the literature can be found. However, these still struggle to find application and diffusion in the engineering practice. On one hand, there is a recognized need to establish agreed and easy-to-apply methodologies. On the other hand, there remains the necessity to describe the complexity of such a phenomenon by embracing a broad spectrum of corrosion-related parameters to adequately describe their consequences. A factor that cannot be overlooked in the modern management of bridge structures is the growing evolution of inspection and structural monitoring technologies, which enable extensive data collection. Parallel to this technological progress, there have been significant advancements in data analysis methodologies. Not surprisingly, in the management of engineering systems characterized by uncertainties, algorithmic decision-making has proven to be a particularly effective resource. These processes use probabilistic methods to simulate the life cycle of deteriorating systems, thus providing a dynamic and adaptable virtual environment capable of integrating with data and on-field observations. Despite these advances, there remains a significant gap in the development of such environments in the field of the life-cycle seismic safety of bridges. This thesis work aims to deepen research in the field of existing reinforced concrete bridges by deepening the understanding of the structural behavior of their critical components. This exploration is carried out through experimental, analytical, and numerical methodologies, thus providing multifaceted insights for the structural assessment. Furthermore, the comprehensive management of bridge structures is deepened by developing and proposing a probabilistic, dynamic, and adaptable approach that holistically describes the seismic structural safety of bridges throughout their life cycle. The results of this research aim to mark a significant advancement in the management of existing concrete bridge structures, aiming to optimize their safety and sustainability. The thesis thus lays the foundations for a comprehensive dialogue, rooted in experimental evidence, to propose practical suggestions for engineering applications and to outline future research in the field.