Over the past decade, the main terminal apron at Tucson International Airport (TUS) was beginning to require heavy maintenance. Cracking pavement was creating debris and the subsequent risk of foreign object damage for aircraft engines. Maintenance personnel at the Arizona airport were consequently spending a lot of time patching the approximately 50-year-old pavement.
"It had greatly exceeded its life expectancy," informs Mike Smejkal, senior director of development services for the Tucson Airport Authority. "It needed to be replaced because it was past the point of maintenance."
In addition, the airport's hydrant fuel system no longer met national fire protection standards, and the existing ground power system needed to be updated to a 90-kVA system. Together, the trio of related projects is expected to cost $42 million.
Project: Apron Reconstruction; Hydrant Fuel & Ground Power Systems Upgrades
Location: Tucson (AZ) Int'l Airport
Cost: $42 million
Funding: FAA Airport Improvement Program (91%); AZ Dept. of Transportation (4.5%); Tucson Airport Authority (4.5%)
Apron Design, Engineering & Program Management: Stantec Consulting Services
Construction Manager at Risk: Granite Construction Co.
Hydrant Fuel & Ground Power Systems Design: Argus Consulting
Electrical: Rural Electric
Hydrant Fuel Mechanical: KEAR Civil Corp.
Hydrant Pits: Cavotec Dabico U.S.
400-Hz Ground Power System: Page Industries
Geotechnical Engineering & Quality
Assurance: Western Technologies
Concrete Structures: West Point Contracting
Surveys: Dowl Hkm; Urban Engineering
Construction Cost & Scheduling:
Faithful & Gould
Materials Testing: Conformatech
Of Note: Uncertain funding disbursements required detailed contingency planning
But when airport authority officials initiated studies for the improvements in 2009, federal funding for such projects was extremely tight. So tight, in fact, that the airside work at TUS was initially projected to take up to 10 years, because demolition and reconstruction were slated to occur on a piecemeal basis, due to the uncertain availability of funding.
Tucson Airport Authority officials, however, convinced the FAA to fast-track the projects by demonstrating that the airport could save about $2 million by taking a construction manager at risk approach and dividing the project into three guaranteed maximum price phases.
"When it's all said and done, the project is going to take around 22 months," says Smejkal. "We were able to show the FAA significant savings if they provided more money earlier, which allowed for construction to occur on both concourses at the same time."
Show Me the Money
The airport's ability to move the project forward without disrupting flight operations was a key cost-saving factor. Planners divided the site into 10 work zones to keep the apron open throughout demolition and reconstruction. With 17 total gates, no more than two per concourse were taken out of service at the same time.
Stantec Consulting Services handled engineering and design, construction and program management, with Granite Construction Co. serving as the construction manager at risk. Working closely with the airport and Stantec, Granite was able to offer suggestions from a contractor's perspective throughout the design process.
Mark Koester, a principal with Stantec, details the rationale behind the approach: "Instead of putting the project out on the street, we selected Granite as construction manager based on their qualifications for doing this kind of work. This allowed us to bring (them) into the design process, and they were able to offer insights into phasing and scheduling that impacted costs."
Using the guaranteed maximum price approach, Granite was required to secure at least three quotes for subcontracted services, adds Koester.
Together, Stantec, Granite and the airport authority developed priorities and expectations in line with the project's design and funding constraints. The team planned and segmented work according to gate closures and operational requirements, developing multiple options so they could adjust depending on the funding available at any given time.
Andrew Rogers, project manager for Granite, elaborates: "If the airport received $12 million, we were ready to build $12 million; if they received $14 million, we had a mechanism in place to grab another piece of work that had already been thought through."
The multitude of unknown variables made the project a complicated one to design, he recalls. The team consequently asked questions, including: What is the fleet mix and how does it affect the movement of equipment into construction areas? How quickly can we complete work? What are the fueling needs and capabilities? "All of these constraints were integrated into a plug-and-play design that could be adapted to whatever funding became available," Rogers explains.
Fortunately, the FAA was able to provide funds on a timely basis. If funding had dried up and construction halted until the next grant was secured, overhead costs would have soared. In addition, contractors would have had to construct temporary transitions between the new and old pavements, which would have added more than $600,000 to costs, Rogers estimates.
"The challenge was working with the FAA to figure out how much money they could allot us each year," Smejkal recalls. "We didn't want to have to shut down and have the contractor leave. It was a balancing act working with Granite, Stantec and the FAA trying to make sure we had enough work to keep our contractors busy until we received the next grant. We were always playing out various scenarios."
Fuel, Power & Pavement
The apron work that began in August 2013 is expected to be complete in May 2015. Starting at the far ends of concourses A and B, demolition and reconstruction is moving steadily toward the center. Approximately 180,000 square yards of the old 12-inch pavement is being replaced with 16 inches of Portland cement concrete pavement (PCCP). In addition, crews are updating the hydrant fuel system and installing a new 400-Hz ground power system.
The old bottom-entry fiberglass hydrant pits are being replaced as apron work proceeds. And the existing isolation valve vaults on the hydrant loop are being moved further away from the terminal to comply with National Fire Protection Association (NFPA) requirements. Crews will also outfit them with positive shutoff double block-and-bleed valves.
Argus Consulting is the sub-consultant planning the new hydrant fuel and ground power system. "We redesigned the piping network such that we could install new points of isolation that accommodated both the current NFPA standards and the phased construction approach for the program," notes Argus Vice President Chris Straub.
To ensure fuel availability throughout the construction process, Argus designed a new truck fuel loading rack. "The old truck rack was outside the secure area of perimeter fence," Straub explains. "To address the phasing issues of the program, we constructed a new truck rack inside the fence. That way, as components of the hydrant system were shut down, the airport had the ability to quickly load fuel into trucks and drive to gates whose hydrant pits were out of service."
The airport's outdated 72-kVA 400-Hz ground power system was replaced with a new 400-Hz 90 kVA system that will support a wide range of aircraft, including Boeing-737s, -757s, and -767s, as well as Airbus-320s and regional jets.
As crews demolished concrete at various gates, subcontractor Rural Electric installed new conduit, connecting it as work proceeded through the work zones. When the apron is completed, crews will pull new cable and connect it to the 400-Hz system located in the airport's Central Room in Concourse B.
Throughout the construction process, the old ground power system must remain operational. Field investigations during the design phase, however, raised safety concerns regarding the potential for crews to hit active power lines during concrete demolition. To allay this concern, subcontractor Rural Electric decommissioned the underground power service and installed temporary conduit and cabling running along the face of the terminal to provide power to gates during construction.
As the apron project proceeds, the airport authority, Stantec Consulting, Argus Consulting and Granite Construction representatives could not be more pleased with the way work has progressed without interruptions. Funding has been timely and project contingency planning meticulous, they note.
"The best projects are always a team effort," reflects Richard Zych, senior associate for Stantec. "The constant collaboration between our team, TAA (Tucson Airport Authority) and Granite is what kept this project moving smoothly from the beginning of the design through construction."
Smejkal agrees: "The contractor, engineer and airport authority - everyone bought into the process. As conditions changed, we found a solution, implemented it and moved on."
He also considers the project well suited for the construction manager at risk delivery method. "It allowed the contractor to perform field investigations during the design process and minimized disruptive conditions that might be encountered once work began. It also helped them understand how the airlines operate."
Next up will be interior upgrades to the terminal building, Smejkal reports, with some work beginning in early 2015 as crews complete the current apron work. "We're working through terminal design right now to optimize our space," he explains. "We expect the terminal work to be completed in 2016."