The Old Skeena River Bridge is a 9-span, 341 m long, single lane bridge consisting of 3 steel stringer approach spans, 5 steel deck truss spans and a steel through truss span, crossing over the Skeena River in Terrace, BC. The structure opened on July 21, 1925, was realigned to accommodate a parallel railway bridge in 1953, and the timber deck was replaced with an open grate steel deck in 2001. The bridge was last recoated in the early 1980s and, at the time of the rehabilitation, still contained red-lead primer.
The project included:
- Close proximity inspection with ropes and ladders (2017) and snooper truck (2021).
- Load evaluation of trusses for verification of existing posted load restrictions and ability to carry the BC Ministry of Transportation and Infrastructure (Ministry) snooper truck inspection vehicle,
- Evaluation of construction lateral wind load capacity during enclosed coating operations.
- Steel coating renewal considering various coating systems and methodologies (overcoat vs. removal and recoating) combined with Life-Cycle Cost Analysis of the different options.
- Installation of 6 new sidewalk refuge bays to accommodate pedestrian movements along the bridge.
- Replacement of corroded steel roller bearings with sliding elastomeric bearings, including strengthening to facilitate bridge jacking operations for bearing replacement.
- Replacement or repair of severely corroded members and plates.
There were numerous challenges and lessons learned during the design and construction process, including:
- Inspection access for truss bridges and determining appropriate levels of expenditure on inspection during the design process.
- Responding to excessive corrosion uncovered following sandblasting.
- Considerations for repairs of historic members – rivet removal and bolt installation.
- Repair details developed during construction for ‘primary’ (truss diagonals and tension chords) and ‘secondary’ (floor beams, stringers, gusset plates and bracing) members.
- Appropriate contingency allowances during construction and cooperation with the Contractor.
This paper describes the project along with solutions and responses to challenges encountered during construction, culminating in several lessons learned that can be applied to future projects.