Iconic Structures of Indiana: IND Airport


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.

Sky plaza

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.

Update from Irvington – New York & Michigan Bike Lanes


The city of Indianapolis has installed bike lanes running from Irvington (Ellenberger Park) to downtown along New York and Michigan Streets. I took some photos of how they have this arranged. Essentially, the bike lanes follow the one-way street pattern and are inside the street parking strip.

Here is a flyer produced by the city and distributed to the neighborhoods near the bike lanes:

I’m stoked about them finishing this, and can’t wait to ride downtown soon to have a pint of beer on Mass Ave. I think the mayor is organizing a ride soon (Mayor’s Bike Ride – May 16th), but he probably has things to do that would cut into my relaxing ride. Of course, this is going to be a very popular place on Bike to Work day – May 15th. If only I worked downtown…

Updates from Irvington – Pennsy Trail


There has been a lot of work going in Irvington in the past year or so. I’ve managed to photograph some of it, figured I would post here to show people that things are progressing along just fine. First on the list is the Pennsy trail.

The Pennsy trail (see original post here) is under construction, I took some construction photos during the nice weather this past week. This phase of construction will link Arlington to Shortridge along the old Pennsylvania railroad line.

Looks like they are stripping the original tracks down a significant amount and re-building the roadway. Should be very good quality and long lasting pathway. Judging from how deep my footprints went, they need to add and compact a bit more soil before they are done.

I was very happy to be able to get to the old rail bridge across Shadeland. This bridge is essential to the success of the trail, because there would be no way to get across a limited access freeway like Shadeland otherwise. A big benefit of this project is that the no-man’s-land in between Shadeland and I-465 is now accessible by pedestrians. Thus, I can now ride my bike to Applebee’s or K-Mart without risking a busy street crossing.

Soon, the trail will be extended to Ritter on the West and underneath the I-465 highway on the East. With a bit of luck, the state will continue its plans to extend to trail to Cumberland, Greenfield, and eventually all the way to Ohio. But the longest journeys start with a single step.

Thermal Insulating Properties of Historic Masonry Buildings


When undertaking the renovation of an historic masonry building, there are two major issues that must be dealt with early in the design phase – what to do about thermal insulation and old windows (I’ll deal with windows on another day). If the building was built before the 1950′s, it is likely that the building was not designed to take advantage of our current HVAC technology, so don’t expect to put in a simple set of ducts and a furnace and move in. As I have been learning more about renovating masonry structures, I have realized it’s much more complicated than that.

The first source of information for any historic project is to consult the Secretary of Interior’s Standards for the Treatment of Historic Properties and the preservation briefs. The standards represent the consensus opinion of historic preservationists and will serve as a guideline for most phases of the project. Some of the requirements may sound expensive or unnecessary, but I strongly suggest following them. If anyone chooses to disregard this advice, please consider doing a lot of research into alternate options before making a final decision.

Keeping heat in your building requires a thermal envelope. When it comes to thermal insulation, brick is a disaster. Don’t let anyone lie to you, this material is a horrible insulator. Sometimes you will read about the benefits of high mass, a mass factor (or M factor), adjusted insulation value, or similar theories. Some of these claims are true under specific conditions, but not in a cold climate. The important thing to understand is that the R value of historic masonry is not high, thus heat and cold will transfer readily through the walls. Masonry walls are typically rated about R = 0.15/in, so a 16″ thick wall has an R = 2.5. Minimum standards for a new building in the midwest are approximately R = 16. This means a modern building has a wall that transmits heat 8x less than a typical historic masonry wall.

This assumes that the R = 2.5 value is accurate, while in reality it may have an actual R = 1.5 or less, there is just so much uncertainty that it is wise to be conservative in your calculations. Basically, the old brick wall is going to need some help in the form of additional insulation. It is possible to add insulation on the exterior or interior, with the interior being much more common because who wants to cover up the facade of an historic building? At this point, we must introduce the next complication: moisture.

Insulating a brick wall by just throwing up some fiberglass batts or foam board puts the brick wall in a bad situation. The wall is the same temperature as the exterior weather, but is exposed to interior air. This will cause condensation on the interior surface, just like the water that puddles around a cold glass during a humid summer day. A typical building has an interior Relative Humidity level of 30% or so. This is a lot of moisture (a lot!), and moisture/water can easily destroy an historic building. If the walls are cold and exposed to the humid interior air, the wall will generate a nearly unlimited amount of water over the life of the building.

Wet insulation has an R value of nil, and wet wood stud walls is a recipe for mold growth. Attempts have been made to reduce the exposure of walls by way of vapor barriers, but this usually just seals in the moisture. Trying to reduce the problem by incorporating vents usually defeats the purpose of insulating in the first place.

As of right now, there is no easy, cheap way to insulate. Large, expensive renovations should consult a specialist when dealing with this scenario, because conventional construction methods will not work. Smaller scale projects should probably base their solution on proven methods, and luckily we now have some great examples. So here are the success stories:

The best one I have seen yet is a renovation done for Harvard University, the Blackstone Office building by Bruner Cott (certified LEED Platinum).

Another source of information is the renovation of the Portland Armory building. This was renovated for the new home of a theater, and they faced many of the same issues as a typical masonry project as well as some special ones because of the large interior spaces. Also certified LEED Platinum.

Finally, the renovation of the Lofts St. James in Montreal. As with this project, any successful strategy involves finding a way to control heat flow, moisture flow, and air flow. Every project is unique, especially when dealing with existing buildings, but there are always ways to get across the finish line.

Categories : green design  resources