ABSTRACT
Impacts of climate change on tunneling projects often focus on the growing demand for replacing aging infrastructure and comparing different alternatives. Leveraging North Amer- ican project experiences, the Climate Change Resilience Assessment (CCRA) methodology helps asset managers and owners decide between refurbishment or new build options, considering this critical yet underexplored factor. Life Cycle Cost Analysis typically considers four primary options: in-place rehabilitation, replacement of main structural elements, construction of a new above grade structure, and construction of a tunnel. Alternatives often include provisions for future infrastructure expansions. The CCRA examines health, safety, operational, and infrastructural impacts of climate change on these options. Using climate data from the National Centre for Climate Services under the high carbon future scenario, the studies extend to the end of the assets’ service life. The analysis focuses on seven climate indicators: hot temperatures, heat waves, heavy rainfall, winter rain on snow, heavy wind, blowing rain, and blowing snow. The seven indicators are selected based on: (1) Past extreme weather events; (2) Historical and future annual and seasonal variations; (3) Significant increases in probability; (4) Local relevance; (5) Potential interactions with project components. Findings highlight varying risk levels for each option, influencing early design choices and comparing underground versus traditional bridge solutions, based on capital expenditure, service operations, and maintenance costs. The CCRA typically reveals significant climate-related risk mitigation opportunities, particularly for tunnels, which show limited impacts from heat waves and heavy rainfall on integrity and operational reliability. Proposed adaptation measures for design, operation, and maintenance aim to enhance resilience against future climate conditions. This comprehensive analysis provides critical insights into the viability and sustainability of underground solutions versus traditional bridges in the face of climate change.
