THE BIG LIFT: Angus L. MacDonald Redecking Project
Location: Halifax, NS
Client: Halifax Harbour Bridges
Duration: 2009-2016
Approximate Value: $165 M
Key Staff: Sarah Hardy, Wade Pottie, Robbie Fraser, Greg MacDonald, Riccardo Ciccarelli, Thomas McNutt
Awards:
Project Description
The Angus L. Macdonald (ALM) Bridge is a 760 m long suspension bridge spanning over the Halifax Harbour. The existing deck and stiffening truss of the bridge was nearing the end of its service life and needed replacement. The project consisted of the design of the new suspended deck and stiffening truss as well as the analysis of the bridge during erection and the design of the main erection equipment. For the duration of this project, Harbourside acted as sub-consultant to Buckland and Taylor.
UPDATE:
Harbourside’s involvement in this project earned it the commendation from the Lieutenant Governor. Harbourside received the Lieutenant Governor’s Award for Excellence in Engineering in 2018 for its work on THE BIG LIFT.
Harbourside’s Role
Harbourside Engineering Consultants had 4 engineers embedded in the design team for this project. HEC engineers were involved in both the analysis and the design of the bridge. In particular, HEC engineers were involved with the design of the deck and stiffening truss, the erection gantries, the temporary deck connection nose, and performed analysis of the bridge during erection.
The deck replacement approach was unique as it allowed the bridge to remain open during the daytime throughout the course of construction. This was achieved by replacing the deck in segments during overnight and some weekend closures.
The existing deck and stiffening truss segment was cut and lowered to a barge using strand jacks on an erection gantry which was supported by the existing hangers. The new deck section was then lifted from the barge and spliced to the previously installed new segment. A temporary connection nose joins the new deck segment with the existing deck. This process was repeated across the entire bridge. This particular erection technique has successfully been employed to replace the deck and stiffening truss on the Lions Gate Bridge.
Unique Challenges
As one of the main access points between Halifax and Dartmouth, much of the Halifax Regional Municipality revolves around the proper functioning and traffic flow of the Harbour bridges. Ensuring that traffic could flow during the day was an essential component to this project, as the city would not be able to tolerate extended closures of the Macdonald.
Social Impact
The continued operation of the Macdonald bridge is essential to life in Halifax. Even with night-time and weekend closures, the city felt deep repercussions from the construction period. However, the renewal of the bridge also means that the city can rely on the Macdonald for years to come. As one of the few connections between Halifax and Dartmouth, and the only pedestrian path between the two cities, the Macdonald is one of the most important bridges in the entire province of Nova Scotia.
