Traffic signals and local traffic management have been removed from Cleveland Bridge, which now has a weight monitoring system in place. ANPR cameras have also been installed to capture the details of any vehicles in breach of the weight limit.
Over the past few weeks engineers have installed the monitoring system which will provide ongoing confidence that the bridge remains safe as it is brought back into service.
It follows a recommendation for a staged approach to reopening the Grade II* listed bridge. Initially, the 18-tonne temporary load restriction will remain and if monitoring shows there are no issues the bridge could technically and safely open to normal traffic loads of 44 tonnes. A passive support system could be designed to provide longer term surety.
Over the spring and summer engineers carried out careful and detailed assessments, as well as further computer modelling, following the discovery of unexpected corrosion in hanger bars at the start of the year. More accurate information on the degree of section loss to the worst affected group of bars became available using castings of the bars.
A detailed report said an intelligent monitoring system would allow the structure to be brought back into service following a period of monitoring under test loads.
Using the monitoring system would provide early detection of the onset of changes in the characteristic ‘fingerprint’ response of the structure and enable the introduction of control measures to ensure public safety in a considered, timely and measured way.
Masonry works, which couldn’t be completed while scaffolding was in place, will continue underneath the bridge for a number of weeks and the contractor’s works compound will be scaled back.