Abstract Manager

In this presentation, we will discuss the successful application of Accelerated Bridge Technology by using an Air Pad Sliding System (APS).  This is believed to be the first application of an Air Pad Sliding System in North America.  The project was completed in a busy area of a major Canadian city and required efficient use of time and space.  By Using the Accelerated Bridge Technology, we were able to ensure the least amount of disruption to the high volume of vehicular traffic, as well as making the most effective use of space in a crowded urban center, effectively reducing urban gridlock. The objective was to design a temporary steel structure and sliding system.   Then, using this system, move a precast bridge into place.  Custom-made accessories and handling solutions were required due to several potential obstacles, including concern regarding the excavation of large amounts of bedrock on sliding weekend as well as extremely low soffit clearance (less than 2 meters of height below the existing roadway). Sliding preparation time took approximately 3 weeks, with the actual slide taking only 8 hours.

The innovative method used in this process was to initially precast the bridge in a staging area just outside of the final position and then, using push-pull units and hydraulic power packs, slide the structure into place with the Air Pad Sliding System.  The total project required 6 months of concrete structure construction, a 23-meter long,  34-meter-wide precast concrete bridge weighing 3800 Metric Tons consisting of 1,518 m3 of concrete and 320 tons of rebar, 4-days of road closure, excavation of  approximately 5,000 tons of backfill material adjacent to the existing highway, 12 hours of line drilling into the bedrock to facilitate excavation, sliding the precast structure over 50 meters, and then 2 days of backfilling and paving before re-opening of the roadway.

 The result was successful completion of the project with little disruption to the daily commuters using this stretch of roadway.

 In conclusion, by using innovative construction methods we were able to complete a project, that using typical construction methods, would have certainly taken much longer and been much more disruptive to the taxpayers and users of this critical stretch of infrastructure. The long-term safety aspect of this procedure is difficult to measure, but one can only assume that with more disruption comes a much greater risk.