Clients / Irvine River Bridge

Location: Elora, Ontario
Description: Complete bridge reconstruction over the Gorge of Grand River
6-Bridge ViewThe Irvine River Bridge is located on David Street in the historic village of Elora, Ontario. The bridge is located at the terminus of a hiking trail on top of the Irvine River gorge and is used as a viewing point of the gorge. Seven different bridges have been constructed over the 25m deep gorge, the earliest one in 1847. The sixth structure was a two-span reinforced concrete open spandrel arch bridge, constructed in 1921 supported by a single masonry pier approximately 22m high, constructed in 1867. The overall length and width were 37.6 m and 7.9 m respectively with a roadway width of 5.35 m and a 1.52 m sidewalk on the south side.

The structure was a provincially significant heritage bridge being a rare surviving example of open spandrel concrete arch construction in Ontario. It is included in the Ontario Heritage Bridge Program’s list of heritage structures.

The principle objective of the project was to replace the bridge with a new structure that would eliminate all of the structural and functional deficiencies of the existing one. A number of site constraints added to the complexity of the construction including:

  • Existing topography precluded any access to the bottom of the gorge by heavy construction equipment – all material and equipment had to be lowered from above.
  • Overhead utilities adjacent to the bridge and road resulted in limited working space for large cranes required to remove the existing structure and to erect the new pre-cast elements.
  •  A regionally significant plant species, Smooth Cliff brake, was identified on the gorge walls and was to be protected during construction.

6-Pre-Cast Arch InstallationA custom environmental protection plan was designed including construction wastewater collection and cleaning system using settling basins. This design specific to the environmental protection plan was approved by the Ministry Environment Canada.

Existing utilities on the old bridge included a water main, sanitary force main, gas main, fiber optic cables and other cables. In addition, overhead hydro cables crossed diagonally over the bridge. All of these services had to be maintained during construction and had to be accommodated onto the new structure.

New horizontal lifelines design was completed for different type of application including all components and anchoring systems. Superstructure removal procedure including structural steel lifting device, design of temporary bracing cables for the removal of the arches and complete lifting procedure. This including several different analyses in order to find the best location of the lifting points including the size of the crane and the spreader beam. Also designed was the entire concrete deck removal sequence with the existing load restriction and the concrete arch removal with saw cutting sequence and procedure.
The new arch ribs were pre-cast on-site based on detailed formwork and arch support design. The spandrel columns and spandrel arches as one piece spanned from abutment to the rehabilitated pier. The four pieces, two per span, were then lifted into place with cranes located on both sides of the gorge

6-Barrier Wall FormworkThe design also features heritage style concrete railings, similar to the 1921 railings and carriage style luminaries and posts.  All include custom formwork design for the new barrier walls.
The new structure successfully addresses all of the functional and structural deficiencies of the previous bridge, while at the same time satisfies local community and provincial interests in heritage preservation and economic value to tourism in the area.