Contents
Background
Design/ Check: DCC Engineering Design Group (EDG)
Contract: NEC 3 Option B
Project Management/ Supervision: EDG
Works Duration: 6 months
Year completed: 2015
Works value: £300,000
Location: Snapper, Barnstaple
In July 2012 Devon experienced severe flood events, from which damage and disruption resulted to the existing highway
infrastructure. Collard Bridge was one structure affected, the existing masonry arch was washed away due to the extreme rise in river
levels and the resulting hydraulic action.
What were the options?
Following a commitment to replace the bridge, DCC engineers appraised various bridge form options.
A “like for like” masonry arch was ruled out based on its susceptibility to damage from high flow river waters. Instead, an
open spanned bridge deck was selected, utilising prestressed concrete beams. This allowed the bridge span to be
increased, maximising river capacity below. Precast beams would also minimise onsite “wet trades”, negate the need for
temporary support works within the river channel, reduce environmental pollution risks and provide a largely maintenance
free structure.
The bridge was supported on piles with the new reinforced concrete abutment and deck monolithically connected to form
an “integral” bridge frame removing the need for bridge expansion joints and bearings, reducing the lifetime maintenance
liability further.
Who was involved?
An Engineer and a Technician from one of DCC’s EDG bridges and structures design teams undertook the project
management, design, detailing, procurement and site supervision.
The scheme was funded from DCC’s Bridge Assessment and Strengthening budget.