Monitoring ship canal bridges.
Latchford high level bridge was built in the 1890's and spans the Manchester Ship Canal 23 metres above water level over a distance of about 60 metres. All of the overturning moments from the cantilevered sections are transmitted as vertical tensile loads to the abutments through vertical ties. It was considered critical to the future safe operation of the bridge (built before motorised traffic) that these ties be not overloaded.
In-situ loads were determined using hole drilling methods. For long-term monitoring, permanently bonded strain gauges have been installed on tie rods and connected to a JF Strainstall instrumentation and monitoring system which sends load data to the JF Strainstall monitoring website every hour. If load readings exceed a predefined amount, a SMS message will be sent to Manchester Ship Canal engineering staff.