Rehabilitation strategy for engineering structures

Like most European road networks, Wallonia’s inventory of structures built primarily between the 1960s and 1980s – the end of the “Trente Glorieuses” (thirty years of rapid economic growth) – shows an age profile indicating a major surge in rehabilitation needs over the coming years. Compounded by maintenance practices that, due to a lack of resources, address symptoms rather than root causes, this situation has resulted in the accelerated deterioration of many structures and a significant accumulation of asset renewal backlog.

The audit’s objectives were therefore to:

• provide an external perspective on the planning process and, where appropriate, propose improvements;
• develop budget scenarios to inform the manager’s strategic choices;
• cover the requirements for rehabilitating assets over the next 30 years;
• provide a tool for investment forecasting and life cycle optimisation, specifically Eqylibr®.

The audit made it possible to formulate recommendations for improving the management system and ensuring the coherent evolution of practices (risk-focused asset condition assessment, optimisation of intervention types, prioritisation of needs, alignment between delivery capacity and the programme, and standardisation and digitalisation of planning).

Furthermore, 30-year budgetary and strategic scenarios made it possible to model the evolution of condition and risk indicators and to determine an optimal investment level. Based on these results, the Walloon Government decided to increase the budget allocated to bridge rehabilitation starting in 2025. This decision was accompanied by a series of changes in budget management, notably the setting of multi-year investment targets for specific groups of structures.

Finally, the availability of the Eqylibr® tool platform and the models developed during the audit allows for projections to be updated and models refined using current data.

Key figures:

6,000 bridges, tunnels and retaining walls