An Overview of the Main Types of Damage and the Retrofitting of Reinforced Concrete Bridges

Restoring and strengthening existing bridges is more economically and environmentally feasible, as cement production in new RC bridges significantly contributes to CO 2 emissions. Additionally, the production of composite carbon materials for strengthening RC structures does not require a large amount of energy, unlike the production of steel for reinforcement, which requires a significant amount of electricity and, accordingly, causes a significant amount of CO 2 emissions. This is why this article presents a comprehensive review of the damage, calculations, and strengthening of RC bridge structures. It examines the main types of damage, including mechanical impacts, material fatigue, corrosion processes, seismic actions, and thermal loads. The mechanisms of their formation, correlations with environmental factors, and operational conditions are detailed. Examples of damage from real engineering objects are provided to assess the scale of the problem. Approaches to the calculation of RC bridge structures are analyzed, particularly methods for modeling the stress–strain state, considering crack formation and material degradation. Key studies by Ukrainian and foreign researchers are highlighted, identifying areas for further methodological improvement. Special attention is given to traditional and modern strengthening methods, including the use of steel elements, composites, and carbon strips. A comparative analysis of the effectiveness of different strengthening approaches is conducted. The conclusion emphasizes the need for further development of existing diagnostic, calculation, and strengthening methods. The integration of innovative materials and technologies is particularly relevant for enhancing the durability of bridges under modern operational loads.