Roughan & O'Donovan was commissioned by Skanska UK to conduct a load capacity assessment of the bridge, with the aim of helping the bridge owner to minimise risk and achieve value for money by avoiding unnecessary strengthening.
Navigation Street Bridge is a 1960’s bridge consisting of concrete-encased steel beams, reinforced concrete slabs, pre-tensioned and post-tensioned concrete.
Our review of the many assessments conducted on the structure between 2004 and 2013 identified a number of opportunities to increase the live load rating, including:
- Consideration of worst credible strengths from testing performed on the bridge
- Application of k-factors from BD21/01 to the Annex D assessment vehicles
- Re-evaluation of the dead load/geometry
- Refinements of the structural modelling
These opportunities may allow the structure to be reassessed deterministically, with the further possibility of a detailed probabilistic assessment as part of stage 2.
Minimising physical works on a structure located at a critical intersection, over the main railway line in the very busy city centre, represented our key challenge.
- Bridge engineering design
- Risk assessment