Our team at N-Force Crane and Equipment, as the steel erector, and Spannovation, as the erection engineer, recently achieved a milestone in the construction of the new Athabasca River Bridge in Alberta. The latest time-lapse video (courtesy of ISL) provides an intriguing look at the process. The video highlights the west side of the bridge, where two girder pairs, each weighing 200 tonnes and measuring 71m in length, were erected.
The erection process began with a crane-assisted launch. The west end of the south pair was initially supported on a trailer and maneuvered backward by a truck. Simultaneously, the east end was lifted by a 500T LTM 1500 model mobile crane. This crane was positioned behind the abutment and in a trench to enable the girder pair launch overhead.
When the pair reached the mobile crane's maximum radius limit, a 400T LR1400 crawler located on the west berm took over the support of the east end using a load transfer triangle. The girder pair continued to launch, with the west end resting on a trailer driven by a truck. Finally, the west end was lifted from the trailer by the mobile crane, while the crawler raised the east end. Together, they executed a tandem lift to precisely position the girder pair. The process was repeated for the north girder pair, showcasing the same complex set of maneuvers.
This method was chosen due to the limited space available on the berms for delivery, assembly, and lifting. Overcoming the challenges of this procedure required meticulous planning, coordination, and engineering. Significant project parties include:
Owner: Alberta Transportation
Designer: COWI
General Contractor: Alberco Construction Ltd
Fabricator: Central Welding & Ironworks
Erector: N-Force Crane & Equipment Ltd.
Construction Engineer: Spannovation Consulting
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