The St Albert Bridge is one of 38 bridges in the Northwest Anthony Henday Drive (NWAHD) Design Built Finance Operate (DBFO) project. This bridge is one of the most technically challenging to design and construct among the 38 bridges of the NWAHD Project. In 2008, the Government of Alberta entered into an agreement with a DBFO team, to construct this $1.42 Billion project. The team consisted of Bilfinger Berger BOT as the financier; Flatiron Construction, Graham Construction and Parsons as the project builders; AECOM and Parsons as prime engineering designers; and Carmacks Enterprises responsible for operations and maintenance. Detailed design began in June of 2008 with construction start-up following shortly thereafter. The main challenge of this project is an aggressive design and construction schedule. Challenges at the St Albert Bridge site included poor soil conditions consisting of saturated silts and site constraints which dictated a Top-to-Bottom construction scheme to meet the required road profile design. These challenges resulted in a unique bridge type chosen to design and construct. The bridge consisted of cast-in-place post-tensioned concrete box girder superstructure, tall concrete secant pile wall abutments and a spaced concrete pile pier. The superstructure was cast on-grade on a sacrificial concrete slab which was removed after completion of deck placement & post-tensioning by excavating down to finished grade. Accessibility for materials delivery/handling was greatly improved by constructing the structure using this method. This paper describes the initiatives undertaken to deliver the project within schedule and budget, including the Top-to-Bottom construction method of constructing the bridge. Factors that impacted the project costs are analyzed and the specific approach adopted for design and project delivery are summarized. Challenges encountered on this project and lessons learned are discussed in this paper. The authors conclude that constructability input is accessible and available to designers and is an integral part of the success in DBFO projects. Collaboration between designers and builders results in a positive effect on project budget and schedule during the construction phase. Finally, recommendations and strategies for future projects are presented.
