Hwy 1 Bradner Bridge Grade Separation
Bridge replacement design on a live highway corridor, at the heart of one of BC’s largest active infrastructure programs.
Client: BC Ministry of Transportation and Infrastructure
Location: Abbotsford, BC
Project Type: Structural – Bridges (as part of a larger, multi-disciplinary project).
About This Project
The Bradner Road overpasses carry Highway 1 over Bradner Road in Abbotsford, forming a critical link in one of BC’s busiest freight and commuter corridors. As part of a major widening of the Trans-Canada Highway from Langley to Abbotsford, the two existing overpasses required full replacement to meet current safety and performance standards. ISL served as design consultant for the bridge replacements, delivering structural engineering services from concept through construction. The bridge work forms one part of a broader multidisciplinary effort spanning highway widening, interchange replacement, active transportation, and environmental design across the full 23 km corridor. Structural scope also included retaining walls for highway widening, the Nathan Creek Culvert to the west, overhead sign structure foundations, and custom barriers.
Before advancing a design, ISL assessed three replacement options against long-term costs, constructability, and site risk. The selected solution uses two integral single-span concrete bridges on steel pile foundations, with retaining walls incorporated to shorten the spans and reduce overall cost. A precast box culvert replaced the existing Nathan Creek structure. All structures were designed to seismic standards. The site presented liquefiable soil conditions and elevated seismic hazard, requiring close collaboration with the geotechnical engineer to develop compatible ground improvement measures and seismic design parameters. The design was developed to account for future highway widening in addition to the current scope.
Because the new bridges sit nearly in the same location as the existing ones, keeping traffic moving on one of BC’s busiest highways throughout construction was a central challenge. ISL developed a staged construction plan to maintain continuous traffic flow and a coordinated signal strategy to manage vehicles on Bradner Road during the work. The fast pace of construction required timely engineering responses to a high volume of contractor submissions, with dedicated project management oversight keeping reviews on schedule. Custom tall wall barriers with glare screens were also designed to improve safety for cyclists crossing the new bridges, following engagement with local cycling groups during design.
Key Features
- Engineer of Record for the Bradner Road overpasses, Nathan Creek Culvert, retaining walls, overhead sign structure foundations and custom barriers
- Two integral single-span prestressed concrete bridges on steel pipe pile foundations
- Three design options assessed against life cycle costs, constructability and geotechnical risk
- Retaining walls incorporated to shorten bridge spans and reduce cost
- Nathan Creek Culvert replaced with a large precast box culvert
- Designed to current seismic standards with ground improvement addressing challenging soil conditions
- Structures future-proofed to accommodate the next phase of Highway 1 widening
- Multi-staged construction scheme maintaining continuous Highway 1 traffic
- Coordinated signal strategy managing traffic on Bradner Road during bridge replacement
- Autodesk Construction Cloud used to manage contractor submissions and track engineering responses during construction
- Custom tall wall barriers with glare screens for cyclist safety
- Part of the Fraser Valley Highway 1 Corridor Improvement Program – a 23 km widening of the Trans-Canada Highway