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Work on Bush Turnpike Retaining Walls in Las Colinas Continues Crews are drilling shafts for 31-foot posts to support new retaining walls at the southwest end of the President George Bush Turnpike (PGBT).
The NTTA’s $26-million renovation project, which began in August 2007, will replace all existing eastbound and westbound retaining walls between MacArthur Boulevard and Los Colinas Boulevard in Irving. The project is expected to be completed this fall.
The new walls are engineered to a higher standard to retain the unstable moving soils in this area. Thus far, crews have concentrated their efforts around MacArthur Boulevard. Now they are working on the Las Colinas Boulevard overpass. Other related construction activities include:
- Constructing footings for the retaining walls
- Erecting the walls and finishing it with a cover, or coping, at the top
- Drilling shafts for the Las Colinas Boulevard bridge abutments
The shafts are produced with a hydraulic drill and boring tool, or auger, attached to a vehicle with continuous tracks. They are 48 inches in diameter and 31 feet deep.
Once drilled, the shafts are braced by a reinforcing-steel cage and then filled with concrete. Footings are placed on top of the drilled shafts, and the walls are erected atop the footings.
Steps have been taken to ensure that both north and southbound frontage roads remain operational during construction.
The new concrete aesthetics on the retaining walls will set the standard for other NTTA facilities, and eventually the same appearance will be used throughout the NTTA system.
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