The effect of degradation on the structural response of a reinforced concrete arch bridge

In recent years, several bridge collapses have occurred worldwide, resulting in human life and economic direct and non-direct losses. Such events are likely related to the age of bridges, which is approaching their lifespan in most of the cases. Furthermore, older bridges were designed according to outdated standards and built by using outdated materials and technologies, and consequently, require major retrofitting. Since infrastructures play a fundamental role in the road network, stakeholders and governance are committed to improve their performance with urgency. Structural safety assessment is fundamental to properly plan and identify maintenance interventions, also accounting for the effects of degradation phenomena. In fact, steel reinforcement corrosion, concrete cracking, creep and shrinkage severely affect expected lifespan of a structural system exposed to external environment and fatigue loads. In this paper, a review of the degradation models available in the literature is provided, discussing the influence of the main parameters on each degradation phenomenon. Subsequently, a numerical model of a case study Maillart’s bridge located in southern Italy is developed, implementing degradation effects to assess their influence on the structural performance. Since the bridge is located nearby the coast, both carbonation and chloride-induced corrosion of reinforcement were considered, as well as longterm physical effects on concrete mechanical behaviour. The results showed that material degradation may influence both local and global response of the structure and that predicting bridge behaviour evolution over time can be useful for its life cycle management.