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Devon’s Bridges (S Devon Branch)
Thu. 17 November 2022 at 2:15 pm
£2 – £4
A talk by Kevin Dentith, Devon County Council’s Chief Engineer, Bridges and Structures about the inspection and maintenance of Devon’s three thousand bridges.
Kevin is a Fellow of the Institution of Civil Engineers, and is Chief Engineer (Bridges & Structures) with Devon County Council. He has worked on numerous steering groups relating to bridge research and more recently bridge scour in collaboration with Exeter University. He manages a large bridge office with 38 engineers and technicians looking after 3,215 bridges and 134 km of retaining walls with an annual maintenance budget of c. £9m. The group has five bridge teams covering all aspects of bridge engineering including Asset Management, Bridge and Retaining Wall Design, Inspections, and Capital Maintenance.
DA members £2, non-members £4. Pay in cash at the door, or in advance by credit or debit card via TicketSource here (for which a small booking fee, minimum 30p, applies).
Report on the talk
Devon has 3,215 bridges, over a thousand more than any other county, and they range in size from very small – such as clapper bridges on Dartmoor – to the very large. The largest bridge that Kevin is responsible for is that over the Teign near Newton Abbot, carrying the A380 over the estuary. Kevin is not responsible for bridges over the motorway nor railway bridges but he is responsible for the 22 road bridges over the railways! He therefore has to work closely with Network Rail when their paths cross. To look after all 3,215 bridges, there is a budget of £9 million which comes from central government, and 5 teams. To replace every bridge in the County it would cost £1.2 billion (yes, billion!)
These 5 teams deal with inspections as well as repairs – routine and emergency. In November 2012 two bridges collapsed due to flood waters on the same day that the canal was breached! Obviously when a bridge is destroyed it can take several years to replace and the disruption it causes to the public can be considerable. Inspections are completed either by CCTV or by personal viewing and as this often involves going below the surface of the water members of the team are commercial diving trained. Also, as the engineers are working in or around waterways, they often come across otters. General inspections take place every two years with principal inspections every six years.
Problems have been identified with the piers on Shaldon Bridge where the timbers inside the casings are rotting so concrete is having to be poured in. Corrosion in the columns was also found at Rock Park Bridge, a cycle path over the waterway, where they had to put jacks in to support the bridge while they repaired it. It cost £2.5 million to repair.
One of the priorities at the moment is suicide prevention. Taw bridge saw 72 incidents in 12 months and 2 deaths. When such incidents occur the bridge obviously has to be closed and a diversion put in place. Initially they put up screens and signs indicating help and assistant for those in distress but there was no significant reduction in incidents. Now Kevin is working with both the Highways Department and Network Rail to build higher barriers to prevent such events.