ABSTRACT
In Italy, most of tunnels and underground structures is over 30 years old; this entails extraordinary maintenance interventions in order to guarantee their functionality in conditions of static and functional safety, as well to ensure the extension of their usefulife period. The first step is the assessment of the general state of conservation of the structures, by identifying and mapping the various phenomena of deterioration and damage, and consequently definingocation, distribution and magnitude of each phenomenon. However, this is not sufficient if we do not assign aevel of risk associated to each critical issue, in order to set the priority areas. Thus, application of risk assessment is the basic tool in order to achieve this goal by ensuring a cost versus benefit analysis for each intervention. In this paper, we describe the approach adopted for maintenance planning in an old service tunnel of a quarry in Italy; we focus on the detailed assessment of the defects as well as on the risk-based criteria used for the selection of maintenance work priorityevel.
