Incremental Launching Case Study #1: Athabasca River Bridge

As part of our Incremental Launching Blog Series, we look at one of the largest scale steel girder launches in North America: the Athabasca River Bridge in Fort McMurray, Alberta. Built in 2009 to serve the growing oil sands region, the structure measures 472 meters in length and required over 6,000 tonnes of structural steel. Of this, approximately 375 meters of deck — nearly 5,000 tonnes of steel — was incrementally launched, making it one of the heaviest steel bridge launches ever completed in North America.

Simultaneous launch of ten girders across the Athabasca River in Fort McMurray, 2009.

The Challenge

The baseline erection concept developed by the designer anticipated that the girders would be launched in two phases of five lines each. A temporary pier was to be placed mid-river at the interface between the launched portion (about 375m) and the flared, stick-built portion at the south end (about 100m). The pier would allow the cantilevered girders to be vertically jacked and spliced to the crane-erected section.

While structurally sound, this plan carried significant cost and schedule implications:

• Mobilizing and constructing a temporary pier in the Athabasca River was a major operation in itself.

• Launching in two separate phases doubled the alignment and splicing risks over water.

• The overall erection sequence was lengthy, raising operating costs.

The challenge extended beyond handling the sheer weight of the girders; it was to find a way to minimize the overall cost and duration of erection operations without compromising safety.

The Value Engineering Exercise

Once the steel erection subcontract was awarded, the erection engineering consultant carried out a detailed value engineering (VE) study. Two key innovations emerged:

1. Launch all ten girder lines simultaneously.

   Instead of two independent launches, the girders were braced together and advanced as a single unit. This eliminated duplicate launch operations and reduced alignment risks.

   
   

2. Eliminate the temporary pier through innovative jacking.

   At the splice location, a controlled jacking sequence was developed. Using the permanent piers themselves, the girders were lowered incrementally — by about 67 mm at pier three and 120 mm at pier four — while holding pier two fixed. This subtle adjustment raised the cantilevered tip sufficiently to meet the crane-erected flared section, removing the need for a costly temporary pier.

   
   

Refer to the previous article on Planning of an Incremental Launch.

The Result

The Athabasca River Bridge was successfully launched in late 2009, achieving the widest simultaneous steel girder launch in North America. Approximately 5,000 tonnes of steel were advanced in a single incremental launch, cantilevering up to 76 meters beyond a pier without temporary supports.

The VE solution offered substantial savings:

• Eliminating the temporary pier reduced cost, complexity, and environmental disturbance in the river.

• A single ten-line launch cut the schedule and lowered operating costs.

• Safety improved, with fewer high-risk splicing operations over water.

Girders upon completion of the launch and removal of the launch nose and prior to splicing with the stick-built segments

This case highlights the power of erection-stage value engineering. By questioning the baseline assumptions and applying innovative jacking strategies, the project team transformed the approach — delivering one of Canada’s most technically impressive and cost-effective incremental launches.

📖 Download the full Bridge Design and Engineering Magazine article below:

2.BDE Athabasca.pdf

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