Added value of monitoring for the maintenance of a reinforced concrete wharf with spatial variability of chloride content: a practical implementation

With 80% of European trade exchange and a key role for European defence, harbours play a major socio-economic role. Inspection of wharves is very expensive due to the difficult access to some components. Reinforced Concrete (RC) structures in harbours are designed for a long service life (50 to 70 years). For RC structures exposed to marine environments, chloride-induced corrosion leads to deteriorations. On-site corrosion diagnosis of RC structures typically consists of Non-Destructive (NDT) and Semi-Destructive Testing (SDT) with large uncertainties and sensitivity to environmental conditions (temperature, relative humidity). Moreover, spatial variability of deteriorations explains why weak parts of the component exist, i.e. those to be repaired or monitored. That requires more inspection for detecting the location of these parts. Embedded sensors reduce these drawbacks, but they involve an additional cost for installation and data treatment. This article analyses the added value of Structural Health Monitoring (SHM) by comparing the maintenance of a RC wharf with SHM to an optimized maintenance based on SDT only. Uncertainty of measurements and its effect on decisions are accounted for. It is shown that the savings on inspection and maintenance with SHM can reach more than 30%.