Decision-oriented resilience for sustainable infrastructure across the life cycle

Abstract Sustainability and resilience expectations for infrastructure are escalating faster than the regulatory and design frameworks meant to deliver them. This mismatch is most acute for ageing critical infrastructure, where deterioration advances more rapidly than standards can be revised, validated, and implemented. Despite growing recognition of this challenge, decision-making on infrastructure adaptation remains fragmented: life cycle environmental impacts, economic costs, structural performance, and service continuity are rarely assessed in an integrated way. Here, we develop a multi-criteria decision-making methodology that unifies these dimensions to evaluate retrofit and adaptation strategies for ageing infrastructure, demonstrated through a landmark bridge case study. Our results show that strategies prioritising system-level transformation with minimal structural intervention consistently outperform conventional approaches, achieving superior trade-offs across resilience, cost, environmental impact, and service life extension. These findings provide actionable evidence for extending the lifespan of ageing infrastructure while reducing environmental footprints and resource intensity, and offer a scalable pathway for aligning infrastructure adaptation with sustainability and resilience objectives under real-world constraints.