Multi-objective optimisation of bridge retrofit and post-event repair selection to enhance sustainability

The decaying state of our infrastructure paired with rising emphasis on sustainable engineering suggests the need for upgrades which are selected based on their ability to provide adequate performance under natural hazards and minimise negative impacts on the three pillars of sustainability: society, environment and economy. This paper poses a framework based on a multi-objective genetic algorithm to help identify optimal retrofit and repair combinations which ensure public safety while minimising lifetime environmental, economic and social performance measures of sustainability for infrastructure exposed to natural hazards. Assessment of the case-study application results reveals the relationship between life-cycle environmental, economic and social indicators of sustainability for a bridge subject to earthquakes. The framework is anticipated to help guide the selection of retrofit and repair combinations by providing a set of ‘near-optimal’ non-dominated solutions, which enhance sustainability while ensuring public safety and mitigating or repairing damage from natural disasters.