What is it about?
Undersea tunnels are exposed to seawater, which causes the steel reinforcing bars inside the concrete to corrode and weaken over time. Because much of this internal damage is hidden, it is difficult to predict when the tunnel will degrade and when repairs are needed. This paper introduces a practical framework to evaluate and predict the long-term health of these tunnels. Our method combines two approaches: A statistical model that assesses the overall, visible condition of the tunnel, which we call "global performance". A specific analysis of how quickly saltwater penetrates the concrete to rust the internal steel, which we call "local performance". We applied this framework to a 50-year-old tunnel, successfully predicting its structural health over 100 years and identifying specific areas needing urgent repair.
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Why is it important?
Previous maintenance methods usually relied only on visual inspection data, which misses hidden internal damage, or on complex theoretical models that are not practical for daily management. Our work is unique because it bridges this gap with a "dual-index" framework. By integrating the overall visible condition with a detailed prediction of internal steel corrosion, we provide a much more comprehensive diagnosis of the tunnel's health. This framework gives tunnel operators and engineers a practical tool to make highly targeted, cost-effective maintenance decisions. It helps them determine exactly when and where interventions are needed, rather than waiting for structural failure, ultimately making infrastructure management more efficient.
Perspectives
Developing this framework was highly motivated by the growing challenge of aging marine infrastructure. We often see a gap between complex theoretical failure mechanisms and the practical evaluation methods needed for daily maintenance. It was rewarding to apply our model to an actual 50-year-old undersea tunnel and see it successfully pinpoint the specific joints requiring urgent repair, while confirming the overall structure remains sound. We hope this practical approach helps bridge the gap between academic research and real-world asset management, providing engineers with a reliable tool to keep critical transportation networks safe and cost-effective.
CHAOJUN CHEN
Shandong University
Read the Original
This page is a summary of: Life-Cycle Structural Performance Prediction of Undersea Tunnel Suffering Chloride Attacks, Journal of Testing and Evaluation, April 2026, ASTM International,
DOI: 10.1520/jte20250548.
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