A new air traffic control tower is always a big deal; but the commissioning at O'Hare International Airport (ORD), scheduled for mid-October, is bound to garner extra attention. The tower's non-traditional angular design will undoubtedly turn heads within the industry, and those who look more closely will find notable eco-friendly elements. Internally, the opening of the new south tower and runway it will serve moves the Chicago Department of Aviation one major step closer to finishing its $8.7 billion airport modernization program.
The long-term initiative is untangling ORD's previous crisscross airfield configuration to create six parallel east-west runways specifically engineered to increase efficiency, capacity and safety at the busy airport. When the new $41 million control tower and $516 million Runway 10R-28L open concurrently, the entire south portion of the modernization project will be complete. The additional tower (ORD's third) was needed because the main tower in the terminal core did not have a direct line of sight to all portions of the new 7,500-foot runway, which is located on the far south side of the airfield. ORD's other tower, located on the north side of the airfield, was completed in 2008 to address line-of-sight issues for Runway 9L-27R.
Jon Leach, chief operating officer for the Chicago Department of Aviation, notes that Runway 10R-28L will be a tremendous benefit to operations at ORD, adding capacity and efficiency - primarily in east flow. With controllers in the new tower directing traffic, 10R-28L is expected to increase arrivals at ORD by 24%, from 92 east flow flights per hour to 114. It is further expected to increase the east flow departure rate by 25%, from 88 flights per hour to 110. "We're going to see significant capacity increases in the east flow as a result of 10R-28L," Leach summarizes.
Project: New Air Traffic Control Tower
Location: Chicago O'Hare Int'l Airport, South Airfield
Owner: Chicago Dept. of Aviation
Height: 218 ft.
Size of Base Building: 10,000 sq. ft.
Cost: $41 million
FAA Funding: $33 million
Construction Notice to Proceed: April 2013
Anticipated Commissioning: Oct. 15, 2015
Program Manager: AECOM
Construction Manager: WSP Parsons Brinckerhoff
Designer: exp US Services
Construction Contractor: Walsh Construction
Sustainability Features: Geothermal heating/cooling system; energy-efficient glass; rooftop green space;
low-flow water fixtures; segmented space planning to reduce energy consumed in areas not occupied by people
Environmental Accomplishments: Sourcing 90% of construction materials locally; recycling 95% of construction site waste; compliance with Sustainable Airport Manual; anticipated gold certification from the U.S. Green Building Council
Key Benefit: Improved traffic mangement, particularly for east flow
Airport officials worked closely with FAA personnel to determine the optimal location for the new south tower. The site ultimately selected impacted some existing tenants, Leach acknowledges. Specifically, work crews had to relocate a fuel line and modify Lufthansa's parking area and United Airlines' cargo operations to make room for the new tower. "We placed it in a location that not only allows us to operate functionally now, but into the future should we wish to redevelop that area," he remarks.
Although the construction site was landside, contractors building the new tower still had to take into account airside operations nearby - especially during inclement weather, notes Andres Garcia of AECOM, the program manager for ORD's overall modernization program.
Crane operations needed to build the 218-foot tower added extra challenges for the project's construction manager, WSP Parsons Brinckerhoff. If visibility became too limited, crews had to pull the crane down to prevent interruptions to operations on Runway 10C-28C, ORD's Group 6-capable arrival runway. Unfortunately, the weather that winter (2013-2014) was unusually harsh, even by Chicago standards. A polar vortex delivered one of the coldest winters on record for the Windy City.
"That hampered us quite a bit," recalls Marc Faulkner, resident engineer with WSP Parsons Brinckerhoff. "We did what we could, and on those days where the cranes were ordered to be down, we shifted crews and did other things that weren't relying on a crane."
Keeping the airfield operating at full capacity while trying to maintain the construction schedule was a delicate balancing act, adds Leach.
Not Your Father's Control Tower
The company that designed the tower, exp US Services, veered from the standard stereotype: a narrow vertical tube with a bulbous round cab on top. Instead, exp created a tall rectangular tower that connects to a long, angular horizontal base. The tower's right angles provide a more efficient, simple and clean layout for equipment, explains exp Vice President Jefrey Jakalski, AIA. The interior floor plan contains corners rather than curves to remain more flexible for future needs. "Technology and equipment change, and it's always FAA staff trying to adapt their existing towers to meet with today's technology," Jakalski relates.
Designers located vertical transportation for the 13-floor tower around the perimeter, rather than running it up the center, per traditional tower design. The two sets of stairs, which started out as a fire code requirement, became feature aesthetic elements. While most towers have a solid center shaft, the north and south facades of ORD's new tower are enclosed in glass and provide an elegant glow at night, explains Tom Hoepf, FAIA, principal design architect with exp. "It gives a nice scale, an identity that is unique to Chicago," he comments. "It's an elegant architectural solution to a really technical problem."
Placing the stairs on the perimeter also presents a "friendlier, transparent face" to those visiting the tower and provides natural daylight to employees working inside, says Hoepf.
AECOM's Garcia describes the design as "timeless and elegant," but also "rather iconic." By using building information modeling (BIM) software, exp helped minimize change orders and design conflicts, he adds. "It certainly convinced us of the value of BIM in the construction industry, and we will look to probably incorporate it in any future vertical development we do here," reflects Garcia.
Green From Top to Bottom
Leach notes that the south control tower project focused on sustainability, like all other portions of ORD's modernization program. "In every facet, we've looked for ways to improve the green elements of what we're constructing," he reports.
Per standard procedure, the south air traffic control tower project followed the Chicago Department of Aviation's Sustainable Airport Manual. In addition, the structure is expected to achieve gold certification in Leadership in Energy & Environmental Design (LEED) from the U.S. Green Building Council.
From the form of the building to the way it functions, sustainability played a major role in the design, says Hoepf, a LEED accredited professional. The structure itself is comprised of concrete - a sustainable and locally produced material. In addition, the base structure and tower were "jump formed" - a technique that allows crews to use the same concrete form as they build vertically.
Long-term, concrete is very durable and easy to maintain, Hoepf adds. Over the life of the structure, maintenance costs are expected to be less than they would be for other building materials.
Garcia notes that the tower's innovative geothermal system takes advantage of a natural resource for heating and cooling: the earth. He explains that a water-and-glycol solution circulates through a series of underground tubes, and thanks to the earth's nearly constant subsurface temperature, the temperature of the solution remains constant and is used for even cooling and heating inside the tower. The geothermal field includes 36 wells, each 505 feet deep.
The building also contains a traditional heating and cooling system, and the two approaches supplement each other, Faulkner notes. Designers predict that the geothermal system will reduce annual energy costs by 14%.
All of the control tower's glass is low-E coated, insulated glass with a ceramic frit pattern that allows it to be transparent but also reduces direct solar gain, explains Hoepf. Additionally, the base building includes an overhang to block the south sun, while vertical sunscreens reduce solar impact from the east and west.
The design of the base building segments different uses into separate areas to maximize efficiency of space, he adds. On the north side, the structure is taller to accommodate mechanical equipment, while the south side - the "people space" - is notably shorter. "People don't need as much volume as big, mechanical equipment," Hoepf explains. "By pulling all people spaces to the south and leaving mechanical to the north, it's a very efficient way to zone the energy mechanical systems within the building."
The roofs of the two base buildings are covered with 10,000 square feet of plants to facilitate stormwater absorption and add insulating value to the structures. Low-flow water fixtures are expected to reduce water usage by 40%, notes exp's Jakalski. A stormwater detention cistern under the parking lot was added to collect runoff from the site.
Project officials report that fully 90% of construction materials for the new tower were sourced locally. "We took care to keep it an open specification process and not sole source anything, but include requirements for locally sourced materials so transportation costs and emissions to the atmosphere were reduced," Jakalski comments. On the back end, 95% of waste generated at the construction site was recycled.
The completed tower was turned over to the FAA in December 2014 for equipment installation and other preparations before its official commissioning on October 15. The FAA committed more than $33 million to fund the $41 million project, including enabling work.
The tower project and associated new runway completes current modernization efforts for the south airfield, which now includes three parallel east-west runways and one crosswind runway. Leach describes the new south airfield as a "safe and efficient operation."
Amid more discussion between the city and ORD's airlines, construction will continue on the north airfield. Leach remains optimistic that the Chicago Department of Aviation will finish work on the north side in the near future to balance out the airfield and complete the overall modernization program.