Soon, nothing will block the view of air-traffic controllers in the new control tower at Indianapolis International Airport.

Now under construction, the 340-ft.-tall air-traffic-control tower (ATCT for short) will be one of the tallest in the country when it opens in early 2006. By comparison, the tower at Chicago's O'Hare International Airport is about 260 ft. tall.

The Indianapolis tower is one of two structures being built by Hunt/Smoot Aviation Contractors, a joint venture between Hunt Construction Group Inc. of Indianapolis and Smoot Construction LLC of Columbus, Ohio. The $32 million project also includes a two-story Terminal Radar Approach Control facility, which goes by the acronym TRACON.

advertisement

The project is part of a grand plan to replace major structures at the airport, said Elizabeth Isham Cory, spokeswoman for the Federal Aviation Administration.

"It's to provide our employees with a state-of-the-art location, and the tower will also help usher in a new era of aviation at the airport," she said. In separate projects, the airport is to construct a new midfield terminal during the next few years, and a highway project is moving Interstate 70 a short distance south of its present location to allow airport expansion.

Two main components comprise the tower structure, said Randy Williams, project manager for Hunt/Smoot. "The shaft is cast-in-place concrete, with a structural-steel cab," he added.

For the shaft construction, Hunt/Smoot made use of a jump-form system.

"Every 9 ft., inside and outside forms were set in place," Williams said. "When that concrete hardened, it became the foundation for raising the forms to the next level."

A 406-ft. boom lift hauled the concrete up to fill the forms, Williams said. The shaft is 28 ft. in diameter, and the concrete walls are 18 in. thick, and it all sits on a 55-ft.-sq., 8-ft.-thick mat foundation, he said.

Atop the shaft is the so-called "cab" structure, a 715-sq.-ft. perch with room for nine controller positions.

The new structures will replace current buildings originally opened in 1972 that include a 140-ft. tower, just four controller positions in the cab and about a quarter of the square footage below.

Cory said that, from the cab, controllers will keep watch over the immediate grounds of the airport and control traffic in an approximate 5-mi. radius. It was up to architect Jim Terada and his team from Teng & Associates Inc. of Chicago to maximize the controllers' ability to see clearly.

First-Ever Design Element

For the first time in any American air-traffic-control tower, innovative design and construction of the cab will eliminate all line-of-sight obstructions, said Terada, Teng's project manager for the airport project.

"The roof of the cab is supported by a single column," slightly offset from the center of the tower, he said. "It allows the entire perimeter of the cab to be butt-glazed."

The firm's design means the cab windows will be free of the exterior columns and window mullions that in earlier tower designs have obscured slices of an airport from the view of the controllers. The 1 3/8-in. laminated-glass windowpanes will be joined by silicone sealants to provide clear, 360-degree vision. Steel elements frame the other occupied areas atop the shaft, and the ancillary floors below the cab will feature aluminum and glass curtain wall and windows.

While controllers in the ATCT cab will handle air traffic close to the airport and on the runways and taxiways themselves, another group of controllers will work about 30 stories below in the 35,000-sq.-ft. TRACON facility. With their eyes on computer and radar consoles, they are to keep tabs on traffic within about 50 mi. of the airport.

The TRACON and its link to the tower are precast-on-steel construction, with metal and glass curtain wall. In addition to the actual air-traffic-control equipment, the building will house a training facility and administrative offices. A full basement below the two-story structure will include emergency electric generators, elevator and HVAC equipment along with other mechanicals.

Has Backup Systems

The Illinois economy overall shows a mixed picture.It is critical that the facility be able to operate under virtually any adverse circumstance, so plenty of backup systems are in the plan, said Nick Georgiou, vice president and principal at Teng.

"There are two of everything, a high degree of redundancy," he added.

"There's a huge uninterrupted power supply system to support all of the computers and FAA systems."

The building itself also must weather adverse conditions, Georgiou added.

"The project did undergo wind-tunnel testing to fine tune the structural design," he said.

Constructing a facility filled with technology and redundancy is not easy. "The very issue of running cable trays 340 ft. high is a major challenge," Williams said. Coordinating the work at the top also was a test of coordination because multiple workers had to share a small number of square feet.

The site's location was a blessing and a curse, he added.

Located "land-side," off of the secure airport grounds, there was little to get in the way of the workers, and no buried utilities to avoid. But because of the lack of utilities, "we had to use temporary power to the site," Williams said.

"The airport is running sewer, water, gas and permanent electric to us from quite a distance."

Airport Has Other Activity

The Hunt/Smoot construction site is only one component of the massive work now under way at the airport. The most prominent element is a $974 million midfield terminal project, including a new terminal, concourse and parking garage as well as site preparation, utility and roadwork, and airfield improvements. The terminal is to open in 2008, and initial sitework began last year.

Farther along is the relocation of about 4 mi. of I-70 along the south edge of the airport to make way for airport growth and allow a new interchange leading to the midfield terminal. Though the roadwork is far from complete, traffic recently was moved to the new lanes of the interstate.

As for the new control tower and TRACON facility, construction is to be finished by February, though it will take another 10 to 12 months to install all of the necessary equipment and make it fully functional.

Cory said the operation will employ about 80 people, including air-traffic controllers, facilities-maintenance personnel and managers. About 30 to 35 will be on-site at any given time, she said.