Balancing emerging risks considering the life-cycle perspectives of submerged floating tunnels for a resilient future infrastructure

Infrastructure expansion considerably contributes to greenhouse gas emissions causing the critical global issue of climate change. In recent years, submerged floating tunnels (SFTs) have thus been developed as a sustainable and efficient solution for crossing large water bodies instead of resource-demanding superstructures (e.g., cable stayed bridges). This research delves into a comparative analysis of two SFT design alternatives: SFTs with pontoons and SFTs with tethers centered on environmental sustainability and long-term viability. By incorporating life-cycle assessments and quantitative risk analysis methodologies, our study aims to ascertain the optimal SFT design for real-world application. Our study embarks on detailed investigations into SFTs and then gathers data on material quantities and LCA studies, identifying potential hazards and comparing life cycle performance. Our new findings highlight the significant advantage of the SFT with a tethered design, which has a lower dependency on materials, particularly steels, resulting in lower CO₂ emissions. Additionally, in terms of risk, the SFT with tethers has a lower risk profile in general, especially in situations, including environmental elements, like rising water levels, potential tsunamis, and storms. This design is a promising solution for sustainable and resilient infrastructure development, coinciding with global objectives to cut down carbon emissions and enrich potential benefits in the face of increasing climatic uncertainties. Not only does this study scrutinize the risk and environmental aspects of both SFT designs, but it also opens the path for future infrastructure projects that emphasize engineering robustness and environmental sustainability.