February 17, 2016
This 246-foot-long (75 meters) pedestrian bridge was erected over the Ottawa Airport Parkway to link the Hunt Club community and the Southeast Transitway in Ottawa, Ontario. The structure is a cable-stayed bridge with two asymmetrical spans, one of 170 feet (52 meters) in length and the other 76 feet (23 meters) in length. The deck is composed of three orthotropic steel deck panels. The bridge opened to pedestrians and cyclists in November 2014.
Initially, the bridge was not designed with a steel deck. Because of a weight issue, however, it was essential to lighten the superstructure. A lightweight, economically feasible and durable deck had to be developed and erected, within a very short timeframe.
Special collaboration: Parsons
An orthotropic steel deck proved to be the ideal solution. Such a deck can be up to two times lighter than a similar concrete deck and is designed for a service life of more than 75 years. It is manufactured and takes very little time to erect at the job site.
The fabrication of the orthotropic steel deck was entrusted to Canam-Bridges. It was a challenging project on several fronts. Special care had to be taken with fabrication methods, in-plant handling and welding sequences, given the dimensions of the three deck sections and their relative flexibility during the fabrication process. It was particularly important to control the deformations induced by welding operations of secondary elements to the top plate of the deck.
For the thin wearing surface, the use of Bimagrip, a highly resistant polyurethane-based product with an aggregate top layer, helped decrease the structure’s overall weight and speed up on-site work. Because this type of wearing surface is installed at the fabrication plant, there is no need to wait until the panels are erected on site and then apply the surface course, therefore reducing the construction schedule.
Once the fabrication of the deck was completed, there was a challenge remaining: delivering 19-feet-wide (5.775 meters) deck sections. Transporting such wide loads requires coordination over the entire trip, and more specifically between the transport companies and various entities such as the Quebec’s Ministry of Transportation, cities of Quebec City, Montréal and Ottawa, and the Ministry of Transportation in Ontario. Efficient planning and excellent cooperation between the various actors made it possible to deliver the deck sections on time.
The orthotropic steel deck supplied by Canam-Bridges significantly reduced the weight of the structure and contributed to successful completion of the project. The decision to use a steel deck allowed addressing the various design and building challenges while meeting the extremely tight schedule of the project.
The Hunt Club Pathway Connection to the Southeast Transitway Station is an example of the potential benefits of using orthotropic steel decks. The Canam-Bridges’ team is extremely proud of its role in the successful completion of this flagship project in the Ottawa region.
CISC Quebec’s 2015 Awards of Excellence – Projects outside Quebec category
Owner: City of Ottawa
General contractor: Louis W. Bray Construction Ltd.
Engineering firm: Parsons
Orthotropic steel deck: Canam-Bridges