River Derwent Underbridge Strengthening

Client: Story Contracting
Location: Derbyshire
Discipline: Structural Engineering

Project Scope
The scope of the project was to deliver critical structural strengthening to the SPC7/8 railway bridge located at the crossing with the River Derwent in Derbyshire. The structure route availability (RA) was substantially limited by common defects at each of the bearing locations of the structure both over land and water spans.

FJD devised a system of both traditional and novel strengthening repairs to ensure that the existing structure could be remediated to provide the necessary structural capacity.

Associated with the works, FJD also undertook review of scour protection measures at the site. Through expert review of site investigations and use of archive, FJD were able to demonstrate that the current foundations were below the threshold for remediation and therefore avoiding substantial costs.

Design considerations
As lifting the bridge to conduct the repairs was not possible, the design team developed a design solution that comprised complex bearing and steelwork repairing techniques.

FJD Consulting has supported the project from optioneering through to construction, thus showcasing our
ability to provide design and consultancy support to challenging schemes over a prolonged period of time.

SOCIAL VALUE & ENVIRONMENT
- Safe construction staging of the complex repairs led to minimal closures of the railway, and restricted works to only weekend and weeknight possession closures. Typically, such a tranche of works would have required significant blockade periods. This maintained services for the public.

- Towpath beneath the bridge forms a key societal and commuting link. It was important that strengthening works could be delivered without severing this connection during the extensive programme. Structured delivery of repairs was needed between FJD and the construction team.

- Phased strengthening works removed any need for River closures. Encapsulation and scaffolding was limited to key areas for strengthening.

- FJD have provided timely and effective site support to ensure that all necessary work staging was completed. Wehave also been part of prioritising key repairs to protect public funding to key areas in liaison with Contractor and Infrastructure Manager.