Smack dab in the middle of Dixie ... that's where St. George, UT is located. Actually, St. George is the population and commercial center of Utah's Dixie; a nickname given to the area when Mormon pioneers grew cotton in the warm climate.
Just a handful of years ago, the city was declared the second fastest-growing metropolitan area in the United States behind Greeley, CO. Located in the southwest corner of Utah, St. George continues to thrive.
With the rapid population growth of the area and tourism increasing, the need for a new airport became vital for the city's future. The old airport was surrounded by development with no room for expansion. The new airport is located approximately six miles southeast of the central business district at the 1,200-acre site of an abandoned airfield that has not seen air traffic since 1961.
The St. George replacement airport plans include a single runway capable of accommodating regional jets as well as other larger aircraft. SkyWest, which is based there, has a continual flow of planes landing or taking off. Additionally, there is quite a bit of private airplane traffic.
The runway will be oriented at approximately 010/190 degrees and will be 9,300' x 150' with future plans for the runway to be extended to 11,500 feet. The new St. George Municipal Airport also includes a state-of-the-art air traffic control tower, which can accommodate future needs.
The city broke ground on the new site in October 2008 and completion of the airport is expected in early 2011. Quality Excavating of St. George is the general contractor on the last phase of the project.
"We're the subcontractor on the job for paving," states Alan Buoy, superintendent with Western Rock Products. "We are responsible for achieving a smooth runway surface consistent with Federal Aviation Administration (FAA) requirements."
Western Rock Products provides asphalt, paving, crushed rock, ready-mixed concrete, and construction services for southern Utah and northern Arizona.
Two weeks to pave
The St. George Municipal Airport runway paving project took Western Rock Products about two weeks to complete. Western Rock paved on an 8-inch base course of of P-209 crushed aggregate, as required by the FAA.
"We placed four inches of asphalt in two two-inch lifts with our paving crew using a track paver equipped with the Trimble PCS900 Paving Control System," Buoy says. "The Trimble system helped us accomplish everything with a smaller crew."
Western Rock used the resources of its local Trimble dealer, Wheeler Construction & Mining Technology, and Trimble technical support to ensure that they were getting the most out of the paving control system.
Specifically, the technicians from Wheeler and Trimble explained that the Trimble PCS900 System will manage three critical factors in the paving process: cross slope or straight edge, longitudinal waves (differential compaction), and elevation grade. According to the technical support, all these factors are difficult if not impossible to achieve all at once with a traditional 2D paving system, which can require multiple lifts to reduce imperfections (e.g., differential compaction).
Western Rock's goal was to achieve all three factors in the first lift using a Trimble Uncompacted PCS Design Surface created in the Trimble Business Center-Heavy Construction Edition (TBC-HCE) software. The Uncompacted PCS Design uses the survey certification data from the finished P-209 base and the first two-inch lift design including a compaction factor. Using this method, the TBC-HCE software created an Uncompacted Design Surface to help manage differential compaction on the first lift. During the runway paving, Western Rock was within spec on all three paving factors on the first lift.