Structural monitoring solutions from asset integrity specialist AV Technology (AVT) are providing Guernsey Water with crucial crack and joint movement readings at St Saviour’s Bridge which spans the dam wall at the northern arm of St Saviour’s Reservoir.

Holding in excess of 1,090 megalitres of water, around a quarter of the island’s water supply, St Saviour’s Reservoir was completed in 1947 after construction work was abandoned due to the German occupation of Guernsey during World War II. The footbridge across the island’s only impounding dam forms part of the Millennium Walk nature trail around the reservoir, and so is in constant use by tourists and local residents.
Operators Guernsey Water were aware of movement in the bridge, and with the structure approaching 70 years old, took the proactive decision to pursue detailed structural monitoring in order to inform future improvement schemes.

"Focusing on three key points at each corner of the bridge, we have installed a remote displacement monitoring system to measure any crack and joint movements, as well as temperature, at 12 positions in total," explained AVT Consultant Engineer Tony Bailey. "With extensive experience in bridge monitoring, we are able to provide simultaneous, highly accurate readings for the factors being monitored under both static and dynamic loads, and with ambient and in-service loadings.

"The bridge will be remotely monitored for a full year, with reporting available instantly to Guernsey Water throughout the programme which will be crucial in determining the safety and long-term durability of the structure."