Detection and monitoring technologies for underwater concrete structural damage: A review

Concrete with exhibit low cost, high durability, and abundant raw materials are particularly suitable for the construction of underwater structures. However, underwater concrete structures are subjected to the synergistic coupling effects of multiple destructive factors, such as scouring, wet-dry cycling, chloride ion corrosion, and microbial corrosion. This renders them susceptible to developing various forms of structural damage, including cracking, reinforcement corrosion, leakage, scour, and concrete cover spalling. Therefore, timely and effective detection holds significant theoretical and practical significance for ensuring the safety of underwater engineering, reducing operation and maintenance costs, and promoting technological progress in the industry. In recent years, damage detection of underwater concrete structures has gradually developed toward high efficiency, intelligence, and long-term automated monitoring, with image processing, intelligent machines, and sensing devices having gradually emerged as emerging means for the detection of underwater engineering structures. First, this article summarized the common structural damage modes and their underlying causes in underwater concrete structures, and introduced embedded sensor detection methods such as vibrating wire sensors, piezoelectric sensors, and fiber-optic sensors. Meanwhile simultaneously provided a comprehensive review of nondestructive testing techniques, including acoustic waves, electromagnetic waves, stress waves, and image recognition, combined with underwater robot inspection. Then, this article clarified the research status of the temperature tracer method for damage detection of underwater concrete structures, conducted a detailed analysis of the adaptability and improvement technologies of this method, and identified effective methods for improving detection accuracy. Finally, this article summarized the current challenges faced by underwater structural detection technologies and prospected the development trends of detection and monitoring technologies for underwater concrete structures.