Sunborne X-Jet Apron - Centennial Airport, CO

Project Focus
This $675 thousand, 15000 square yard by 9.5” thick PCCP apron, was constructed for the Owner, Sunborne Development, at Centennial Airport to serve two new hangars for the time-share airline X-Jet. Construction Manager Shaw Construction subcontracted the high production, slipform portion of the apron to IHC.

Project Details
Schedule & Complexity
To maintain the clear zone requirements of the runway and to avoid line-of-sight conflicts from the tower to the taxiway, the only space available at the airport for the concrete plant was the current construction site, which was also needed for storage and staging for all of the other subcontractors building the hangers. Aggregate stockpiles could not exceed 12 feet in height. The potential problems associated with this tight construction area were overcome by the cooperation of all subcontractors and the general contractor.

Construction & Innovation
The Contractor cooperated with the Engineer and Owner to refine the pavement structural design for actual subgrade conditions, reducing the pavement thickness while accommodating a larger design aircraft, and saving nearly $200,000. The Contractor was required to submit a jointing plan designed to match the existing joints of the apron to the north and the lay out of the hangars and supporting offices. The Contractor proposed an alternate geometric plan, eliminating the long radii curve at the edge of the new apron, providing for a zig-zag square edge pattern that will facilitate the next phase of the apron construction and will save time and money for the future expansion of this apron. For safety the apron edge was striped on the long curved radii.

It was essential to provide access to the hangar construction area at all times. A 30-foot buffer was kept between the apron construction and the hangar. Shaw issued a separate contract to the building flatwork contractor for the final tie-ins to the hangars, coordinating the schedules and phasing as necessary to provide full time access for all contractors working in the confined site.

All of the storm water from the apron and hangar drained into this 30’ access corridor. The Contractor and Shaw worked together to mitigate the impacts of some major rainfall events, providing positive drainage throughout each construction phase to assure that construction could continue as soon as possible after the rain.

For safety reasons, the Contractor worked several weekends to minimize the construction traffic and congestion during the aggregate base haul and placement.

GPS was utilized for finishing the sub grade and placing the aggregate base eliminating the need for blue tops, and expediting the project. The contractor also verified the drainage by viewing it on the computer prior to sub grade work.

A CMI 350 paver was used to place the PCCP. The concrete was batched on site in a Hagen 9 cubic yard batch plant, and because of the proximity of the plant, concrete was transported to the paver using only two 10-wheel dump trucks. A soft cut saw was used for the green saw cutting. This eliminated the slurry from the saws and most of the work was able to be completed during the daylight hours. The Owner was so pleased with the appearance of the widened and beveled joints, that a contract modification was issued to reseal the joints on the 7-year old adjacent apron using the same methods.

Quality
All strength and quality requirements were met, with no grinding required to meet the smoothness specification.