Alberta Transportation completed twinning 140 km of the existing two-lane undivided Hwy 63 from Atmore to Mariana Lake. As part of this project, several river crossings are required including a new bridge over the La Biche River on the new northbound lanes paralleling the existing structure. Associated Engineering provided preliminary and detailed design, and construction and post construction services for this project. Bridge construction was complete in October 2014.
The bridge planning phase recommended the installation of pile shear walls at the toe of the headslopes to support the fill, with a separate clear span bridge. Because of the high horizontal forces pile tie-backs were also required.
An innovative solution involved creating a rigid frame structure with pile walls incorporated into the structural foundations. The bridge is founded on 1.5 m diameter, 20 m deep concrete piles, with each abutment having 9 piles spaced at 3 m centres which support both the structure and the horizontal slip plane forces. The superstructure spans 40 m and comprises four lines of 2.0 m deep precast NU girders with a cast-in-place concrete deck. The frame moment-connections are made through the use of a diaphragm wall cast continuously with the deck connecting the superstructure with the abutment.