Location: Guernsey
Castle Cornet Bridge provides the sole access to Castle Cornet, a historically and culturally significant structure forming part of Guernsey’s coastal defences and breakwater. Following a successful alternative tender, McFarland Consulting Ltd were appointed to undertake a detailed assessment of the bridge structure to support continued safe access and long-term asset management.
MCL initially completed a comprehensive programme of inspections and investigations to establish the condition of the reinforced concrete elements. This included visual, geometric and delamination surveys, supported by an extensive suite of non-destructive and intrusive testing. The investigations were designed to characterise material condition, identify deterioration mechanisms and assess the extent of active reinforcement corrosion within the structure.
Based on the findings of the condition assessment, MCL developed a finite element analysis (FEA) model of the bridge representing the deteriorated state of the structure. The model was used to identify areas experiencing the highest stresses and to inform the placement of structural monitoring instrumentation. To verify and calibrate the analytical model, fibre optic strain sensors were installed at key locations and a series of dynamic load tests were undertaken.
The monitoring system has remained in place following completion of the testing programme and continues to provide data on the ongoing structural performance of the bridge. The combination of detailed investigation, calibrated structural modelling and long-term monitoring has enabled informed decisions to be made regarding the continued use of the bridge, ensuring safe access to this important heritage asset while managing risk and avoiding unnecessary intervention.
