LEA was awarded the preliminary assessment of feasible structure types and configurations, and the detailed design, for replacement of the Fergus Road Bridge — originally built in 1951. The LRB is located on Bourinot Road in the Township of Opasatika, Old County Cochrane, New Liskeard District, over the Opasatika River.
The existing bridge is a 5 span 30 m long and 5 m wide, consisting of sawn girder approach spans and a steel girder main span. The existing bridge has a triple load limit posting. The replacement is a 5.5 m wide 39.5 m span modular bridge clear spanning the Opasatika River.
LEA has worked on the evaluation of three superstructure options and four alignments and staging options for the replacement.
LEA has faced several significant challenges when tackling this project:
- A staged replacement was not a viable option, as it is a single lane crossing.
- For realignment options either to the north or south of the existing bridge, a two-span bridge with an in-water pier would be required to avoid filling into the river, and the 2 months required to build the in-water pier after the June 20th in-water work restriction would push completion of the bridge well into late fall of 2017, with a potential for a carry over into the next season.
- Tasked with developing a modular bridge option to clear span the river and replace the bridge in a 9-day full closure of the road to minimize delays to public.
LEA successfully designed around the project challenges and presented intuitive solutions:
- Temporary single lane daily closures were required when the new road alignment was tied-in to the existing platform at both approaches.
- Detail design of a modular single span bridge requiring no in-water pier to avoid in-water work restrictions that would constrain the construction contract.
- The complete removal of the existing bridge and construction of new bridge in 9 days (9-day full closure) – A strategy that avoided the additional costs (80% additional), environmental, and construction schedule impacts of doing a single-lane detour or realigning the crossing.
Construction mobilization started in the beginning of August and is to be completed by the end of September, 2017.