The Indianapolis Midfield Terminal is a lesson in successful long-term infrastructure planning. The site of the airport was picked in the 1930’s, the “temporary” terminal was built in 1957, the upgraded control tower was finished in 2006, and the current terminal was finished in 2008. The current location was picked over 70 years ago, and the wait has been worth it.
South elevation and main entry
As is customary, I would like to refer readers to my fellow Indianapolis A/E bloggers and their thoughts on the new airport:
Urbanophile (start here and find links to all 7 pieces)
Circles & Squares (pre-construction review here, great photos too)
The new terminal is a great piece of infrastructure because it has made the Indianapolis Airport one the most convenient, comfortable, and successful airports ever. The iconic structural elements including the exposed roof trusses, vertical bowstring trusses, and eccentric braces give it an open, industrial grandeur. The structural system is easy to comprehend and the building feels safe and comfortable inside.
Interior of plaza (construction)
One of my favorite structural features is the column/brace system supporting the main roof. Depending on which direction is considered, the members will act as a column or an eccentric brace, and no moment connections were required. The trusses above did require a little bit of extra detailing, I’m sure, but everything looks great and I’m sure the system performance had to meet strict requirements with all those windows.
Brace columns and skylights
Pin connections at column base
I asked the original designers about these columns. I never got a clear answer about what seismic classification was used, but I would bet they considered them eccentric braces. The connections were designed as conventional pins per AISC specifications. They pointed out that while the trusses and braces were different from typical construction, the contractors were experienced with this type of construction and thus construction problems were limited.
Another unique element used on the airport is the vertical bowsting truss. These trusses are used on the huge expanse of glass fronting the passenger drop-off area, resisting the large wind forces that develop on this face. The open web design matches the architectural style of the interior, and the ratio of open-ness allows natural light to filter throughout the building.
Bowstring window trusses near public plaza (construction)
Vertical trusses near front entry (construction)
Much of the project was LEED registered (still awaiting USGBC confirmation), and it is clear that some sustainable thinking went into the project. A good writeup of the Airport’s efforts towards acquiring LEED certification is here, or you can visit Blackburn Architects who were responsible for managing the LEED documentation (but you must use IE not Firefox).
Roof detailing on eastern side (construction)
Braced column supports and art space below (construction)
This was the first terminal to open under the new regulations passed since the 2001 terrorist attacks. A great deal of planning went into ensuring this airport would be able to meet all of the new regulations enacted to tighten security. Several areas of the airport are hardened against natural and manmade hazards, and new technology rapidly screens problems out of the system in case anything strange is found.
Tornado shelter entry
The front approach from Interstate 70 is convenient, and the traffic arrangement on the airport property is simple yet logical. Economy and long-term parking is the first option, and it sits in a field dominated by the new control tower. The tower makes it easy for people to orient themselves, even with the tall berms obscuring any other visual landmarks.
Air traffic control tower
Next up is the parking garage. This pre-stressed concrete structure has some really cool features that raise it above the banality of most parking structures. Several locations are high-lighted by tensile membrane roofs. The corkscrew vehicle ramps add flair to the southern corners, while the central pedestrian area is covered by another fabric roof. This central pedestrian area is actually quite attractive. There are automated people movers, glass enclosed elevators, kinetic sculptures, and a ground transportation center directly across from the main terminal.
Corkscrew vehicle ramp membrane structure
Tensile membrane roof over parking structure
The bridge structure linking the parking structure and the terminal is basically a trussed pedestrian bridge. Automated people movers and a central aisle are covered with an amazing bit of public art. This multimedia installation involves sound, light, movement, and sense of awareness that makes the traverse across the bridge an interesting experience. The bridge delivers travelers to a mezzanine level with escalators heading up or down.
Pedestrian bridge and front entry (construction)
The up option delivers another great experience as the expansive main plaza opens to view as you raise up to the main floor level. This room contains all of the ticketing areas and while there is no easy way to find where each airline is but the area is small enough, and interesting enough, to encourage a bit of exploration.
Main ticketing and entry lobby (construction)
On the way towards the gates and security areas is the circular plaza that establishes a special place within the airport. The circular public area is surrounded by retail and food establishments, which is one of the best public spaces in the city. The translucent roof panels add natural light to the space, and the hanging arts offers a visual reward for looking upwards.
My favorite part, however, is the elevated catwalk that rings the public space. This links the administrative areas on the east and west wings, but it adds a new dimension of walkable space that really helps to enclose the area. It is a shame that the city has not learned how to apply these concepts to the cityscape, there are many places that could be reclaimed for pedestrians in a simlar manner.
Public space lined with shops
Upper walkway with torque-tube (construction)
Passengers can go through security at either concourse, each has plenty of queuing room and the latest equipment that speeds people through the checks. This in contrast to the previous Indianapolis security experience, and to many other airport terminals around the country which were not built to handle the new security provisions. Both security check areas have a large mosaic that adds visual interest.
View of the sky plaza and terminal from the tarmac (construction)
The A/B terminals offer a more typical experience, each gate has a seating area and the central area is taken up by automated people movers. The best part about these wings is the high ceilings and exposed structural members. The roof trusses and use of glass really shows the modernity of the airport. Once again, this is a night and day contrast with the previous Indianapolis terminal. While the overall feeling is still an industrial and impersonal one, the space is less depressing and fills travelers with confidence rather than despair.
Terminal A with Automated People Mover
Terminal structure with eccentric braces and steel trusses
Incoming passengers can easily find their way to the baggage claim. The automated baggage handling system takes up most of the space below the main floor. The system quickly routes each incoming and outgoing bag to the correct destination. It is so quick that it is possible for your bag to be waiting for you at the baggage claim before you are even on your way down the escalator. Siemens designed and installed the baggage system (more info here).
Braced steel frames and mechanical systems in lower level (construction)
One small turn within the 13,000 foot baggage handling system (construction)
The passenger pickup and dropoff area has been used to showcase even more structural elements. The cantilevered bus stops are similar to units covering the ticketing areas, tying the different areas together with a cohesive architectural style. The pickup/dropoff area has a great vista to the south, but it doesn’t feel too open because the large glass backdrop provides a sense of enclosure.
Lower level exit from baggage claim to ground transportation
In general, one of the reasons that the airport seems so large is that people move through it so quickly that there are no large crowds of unhappy travelers. The limited time I have spent in the airport has been full of the typical travel issues: tickets lost in the computer system, baggage fees, expensive long-term parking, and neck cramps after falling asleep on the plane. But, it is all much more bearable when you aren’t trapped in a building that looks as much like a military bunker as it does a functional piece of transportation infrastructure.
Baggage claim area (construction)
Baggage claim area
The airport managers realize that long-term planning allowed Indianapolis to accommodate the future growth of the airport corresponding to the growth of the city. They have further realized that expansion may be necessary in the future. This future expansion is provided for by adding extra gates in the A/B concourses. Room for an extra runway is located across the interstate.
The unused space between the parking structure and the nearest parking lot is expected to be taken up by a special-purpose hotel and convention center. I have even heard that there is an on-site location that can be used to link up to a mass transit system. If you don’t think that is the definition of long-term planning, then you haven’t spent much time in Indianapolis.