Award of Excellence North Channel Bridge Replacement

At the international border crossing between Canada, the U.S. and the Akwesasne Mohawk Community on Cornwall Island in eastern Ontario, the North Channel Bridge Replacement – Three Nations Crossing replaces an existing high level bridge. The existing bridge – now being demolished – dates from 1962 and had reached the end of its serviceable design life.

Morrison Hershfield was retained by the Federal Bridge Corporation Limited (FBCL) to provide consulting engineering services for the construction phase of the new low-level bridge. The new bridge is adjacent to the old one, approximately 17 metres apart.

The project faced many political and technical constraints. The first contract involved the construction of three in-water piers within the fast flowing waters of the St. Lawrence River North Channel. Highly technical marine equipment was needed and was anchored to the piers of the existing high level bridge for stability. Steel caisson liners were drilled 6 metres into the bedrock below the river bed, then construction of the piers was staged to the pier cap level using barges to deliver reinforcing steel and concrete to the pier locations.

Launched box girders

The second contract was the construction of the bridge structure, approach detours and roadways. The superstructure consists of twin steel box girders with a concrete deck. The steel was placed from the north abutment using a complex innovative launching procedure that rolled the girders across the channel into position.

The design of the bridge specified two parallel rows of 11 box girders. The box girders, made with steel plate up to 60 mil thick, measure 3.6 m wide, 3.2 m high and about 30 m long. They weigh as much as 85 tonnes.

A series of 11 launches were required over a three month period. Upon completion of the girder placement the girders were jacked to remove the launching rollers and place the bearings. The installation, which required precise modeling to ensure not to overstress any part of the structure during the launch sequence, was closely monitored by Morrison Hershfield staff.

Innovative concrete deck

The concrete deck for the bridge was constructed using a National Research Council of Canada (NRC) experimental concrete mix design. Developed by Dr. Daniel Cusson of NRC, the high-performance concrete is designed to minimize shrinkage, while maintaining all of its structural properties and being less prone to cracking. This new product could potentially increase the lifespan of concrete bridges by up to 40 years.

Morrison Hershfield staff coordinated the scheduling of NRC, Aecon and Lafarge Concrete staff to address the requirements for the concrete placement and placing of monitoring instrumentation within the formwork.

Toll plaza at fast pace

Under a very tight schedule for opening the new crossing to traffic, the FBCL commenced work on a new toll plaza immediately north of the low level bridge, along with a new Canada Border Services Agency control facility. Phase 1 of the facilities costing over $10 million needed to be completely constructed in four months.

To accelerate construction, FBCL asked Morrison Hershfield to provide contract management assistance for the procurement of all sub-trades and to provide on-site coordination, integration and scheduling. The work was completed and commissioned on time and budget. During the construction phase Morrison Hershfield worked closely with FBCL, CBSA, the city of Cornwall, and the Mohawk Council of Akwesasne.

Opened in 2013, the crossing gives international traffic direct access to downtown Cornwall and central areas, providing an important transportation link for the people of Cornwall and Akwesasne that will support future growth for both communities.

Morrison Hershfield is providing construction administration services for the decommissioning and demolition of the 1960s high level bridge, which is expected to be completed by June 2016. cce

Project name: North Channel Bridge Replacement – Three Nations Crossing, Cornwall, Ont.

Award-winning firm (contract administrators): Morrison Hershfield, Ottawa (Stan McGillis, P.Eng., Robert Goulet, Arminda Bracaj, Mel Thompson, Brian Bellenger, Patricia MacNeil, Patrick Roger, EIT, Dragos Vlaseanu, Lauren Adams, Wiebe Hoogland)

Owner/client: Federal Bridge Corporation Limited

Other key players: McCormick Rankin (bridge design); WSP (civil engineering), AECON (contractor), American Bridge

Company Canada (in-water works contractor), Seaway International Bridge Corporation (bridge operator)