There is a 195-foot tower crane standing near the middle of the busiest airfield in the country, and as of this month it is setting structural steel.
That is the current state of O'Hare's new Concourse D — the piece of the airport's modernization program that is actually moving while the headline project, the O'Hare Global Terminal, sits further out on the calendar. Foundations went in through 2025 and the first part of 2026. Vertical construction started in the spring. The midfield cooling plant took its first steel at the end of July, and Concourse D steel erection began in August.
What is being built
Concourse D — formally Satellite Concourse 1 — is a roughly 580,000 square foot building. The 2025 groundbreaking materials listed 590,000 square feet; 2026 project updates use 580,000. It stands 73 feet tall across three levels, with a 40-foot atrium at the north end under an oculus roof feature.
The gate program is the interesting part. Nineteen gates are laid out for narrowbody aircraft, and 18 of those 19 can be combined into nine widebody positions. That is not a striping exercise. Swing gates drive apron geometry, structural bay spacing, the placement and reach of boarding bridges, and the utility and fueling infrastructure under the pavement. You build the flexibility in on day one or you never get it.
Passenger space includes more than 20,000 square feet of lounges, 30,000 square feet of retail and dining, and a 450-square-foot children's play area. The concourse functions as an extension of Concourse C and connects back to the existing terminal complex; temporary gates were added to Concourse C during the preparation phase to hold capacity while this work proceeds.
The scope also carries a new central cooling facility in the center of the airfield, plus pavement and utility work sized to support a future Concourse E.
Who is building it, and why the delivery method matters
The owner is the City of Chicago through the Chicago Department of Aviation. AECOM Hunt, Clayco and Bowa hold the work as a joint venture, serving as construction manager at risk. Skidmore, Owings & Merrill leads the design with Ross Barney Architects and Juan Gabriel Moreno Architects, with Arup on engineering.
CMAR is worth pausing on, because the outcome here is the part that almost never happens. Under construction manager at risk, the CM comes on board during design, prices the work as the documents develop, and eventually commits to a guaranteed maximum price. If the job comes in over that number, the CM eats the difference. If it comes in under, the savings terms are set by contract.
In May 2026 the city announced a GMP of $1.455 billion for the concourse — at least $21 million under the approved budget, reached less than a year after construction started. Separately, the project is described as about $1.3 billion for the building plus roughly $300 million in related airfield infrastructure. The whole thing sits inside ORDNext, the city's $8.78 billion O'Hare modernization program — one of the largest of the programs that drove US airport capital spending to a record $28 billion in fiscal 2025.
An under-budget GMP on a billion-dollar aviation job in 2026 is not normal. For contractors weighing whether to chase CMAR work versus hard-bid public jobs, this is a live example of the argument for early contractor involvement: the CM had the drawings in hand while they were still changeable, priced against a real market, and locked a number before the escalation exposure ran the length of the job. Anyone building a bid strategy around delivery method should be tracking construction cost data against outcomes like this one rather than against sticker prices at groundbreaking.
The foundations are the hard part
More than 90 percent of the deep foundation elements — caissons — were complete before vertical construction started, with roughly 35 percent of total foundation work done as of mid-2026.
Caissons on that scale are a soils answer, not a preference. O'Hare's midfield is decades of filled, graded and re-graded ground built up around active runways and taxiways. Spread footings on that material are not a serious option for a three-level, 73-foot building, so the load goes down through drilled shafts to competent bearing. It is slow, it is expensive, it is largely invisible in a rendering, and it consumed the better part of a year before a single beam went up.
That sequence is why the tower crane erection in July 2026 read as such a milestone locally. Foundations at 90 percent of the caissons plus a crane on site is the point where the schedule shifts from ground work — where you find surprises — to structure, where you can plan.
Building inside a live movement area
Everything about this job is shaped by the fact that O'Hare does not close.
The building is going up in the airfield, not on a landside parcel. That means the site is inside the airport's secured area, and every worker, tool and truckload that reaches it has to get there through an operating airport's access controls. Site preparation began back in 2023 specifically so that the disruptive groundwork — pavement, utilities, the routing that lets construction traffic move without crossing active aircraft movement — was resolved before the building started.
A 195-foot crane standing near the center of a working airfield is its own coordination exercise between the contractor, the aviation department and air traffic. So is the central cooling plant, which sits in the middle of the field and needed its own steel package. The concourse itself has to be tied into an existing concourse whose gates keep boarding passengers throughout, which pushes tie-in work into windows the airport can absorb.
None of this shows up as a line item. It shows up as productivity: fewer working hours in a shift once you account for access, tighter laydown, staged deliveries, and sequencing that a landside job would never accept.
Labor
The city puts Concourse D at about 3,800 construction jobs, with union apprenticeship programs built into the program. As of May 2025, the wider O'Hare 21 capital program reported 37 percent combined minority- and women-owned business participation.
Staffing an airside job also means staffing to a badging pipeline, not just a manpower curve. Every trade worker who needs unescorted access to a secured area has to be processed before they are productive, which makes late crew ramp-ups slower than they would be on an ordinary commercial site. Contractors who have run airport work plan the paperwork the way they plan a steel delivery. With steel erection just starting, the ironworker and then the mechanical and electrical curves are about to climb — and structural pricing on a job this size moves with the broader steel market.
Where this sits in the bigger program
The sequence at O'Hare was reordered after a May 2024 agreement between the mayor and the airlines. Satellite Concourse 1 — this building — got built first. The O'Hare Global Terminal, the centerpiece that handles international-to-domestic connections, is now tracking to 2032. Satellite Concourse 2 pushed out to 2034.
That reordering is why Concourse D is racing while the Global Terminal is still a rendering. It also means this concourse has to carry real operational capacity on its own from late 2028 until the rest of the program catches up, which is part of why the swing-gate flexibility matters so much.
What happens next
Steel erection through the rest of 2026, then enclosure, then the long interior and systems phase that decides whether late 2028 holds. Watch for the concourse to top out, and watch the midfield cooling plant, which has to be running before the building's mechanical systems can be commissioned.
For subcontractors, ORDNext is a multi-year procurement pipeline — mechanical, electrical, curtain wall, interior packages on this building, and then the Global Terminal behind it. Public solicitations tied to that work are the kind of thing worth monitoring on Buildermuse's bid feed.
