SOM created the ‘smartest building in Chicago’ with a terraced form designed to bridge the gap between its historic low-rise and high-rise context. Its architect gives James Parker the lowdown on reaching high levels of workplace sustainability
SOM, working for client developers Thor Equities and QuadReal, have completed a 100 metre tall, stepped office building at the edge of one of Chicago’s fastest growing neighbourhoods, the former meat packing district known as Fulton Market.
The tower, which includes retail as well as office floors, was constructed by Lendlease and is LEED Platinum and WELL ‘V1’ Gold. This places it at the highest end of the city’s new sustainable office buildings, and includes what the architects call “pandemic-responsive design features.” These range from seven landscaped terraces running the length of the building, providing indoor/outdoor workspace, to “assistive smart building systems” to optimise performance efficiency and user comfort.
With sustainability accreditation becoming much more in demand by major commercial clients, tenants so far lured to this fashionable new district of the city include healthcare provider The Aspen Group, and farming equipment giant John Deere.
Background
Thor Equities, based in New York, had “recently had quite a bit of success with a recently completed renovation project of a historic building right down the street,” 905 West Fulton Market, says project architect on the new scheme, Kevin Rodenkirch. “They were able to attract a large snack manufacturer, Mondelez, to move their headquarters there,” adds the architect, who has experience in very competitive commercial schemes with tough energy targets, like Broadgate in the City of London, and 100 Mount Street in North Sydney, Australia.
The developer then turned its attention to the site of what is now 800 Fulton Market, buoyed by having sold the completed building for a price per square foot that was a record at the time in the city, and a construction boom since McDonalds moved their headquarters to Chicago in 2018.
Rodenkirch says that while SOM’s architects were working from home during the pandemic, and city administration was supporting nearby restaurants under threat by pedestrianising parts of Fulton Market, “construction was going crazy in the area.” SOM revisited some aspects of the new scheme, having finished their design just before the pandemic hit in 2020.
Covid has added further impetus to the previously muted attempts in commercial buildings to offer staff generous access to exterior spaces, on staff wellness grounds. Kevin says clients now see it as an essential differentiator to give their workers outside space and fresh air, and the new scheme is a great example: “Access to the exterior wasn’t always a big thing in the office market, but now it is.”
Site
With the area having been a meat packing district, the historic vernacular is characterful three to five storey brick warehouses, many being former cold storage, as a result, many are being renovated. The result is a “preservation of a massive amount of the character, and a lot of schemes have been renovations with small additions.
In 2016, Chicago planners decided they wanted to expand the downtown area in a “very direct way,” creating three ‘expansion zones’; here in Fulton Market, as well as two to the south and the north west. This allowed the floor area ratio (FAR) to “jump quite a bit,” says Rodenkirch.
The building faces Fulton Market, sitting at the edge of the historic district to the south. So the architects had to strike a balance between providing a lot of floor area (about half a million square feet), and three and four storey historic brick buildings. The question was, “how do you put this much area on a site when you are right next to this very lively, historic street?”
Design process
Despite SOM’s vast experience in the city, this was their first project with Thor. “When we met with them it became pretty clear they had very aspirational goals, both in performance but also design.” The architects were also attracted by the fact they had secured funding, had a “tight timeline,” and they “knew what they wanted.” He adds: “They said you have to give us something that’s going to be hyper-competitive,” (there were several competing schemes under construction in the area).
The architect asserts this was “kind of a best-case scenario, because if you were going to build here, you had to do something special, in terms of both the quality of the building and its performance.” He adds that it’s a strategic focus of the practice to encourage clients to go further on sustainability: “We knew energy goals were going to be difficult, but that’s what we are looking to do – high performance, and net zero buildings.” The client was “very hands on,” insisting on weekly meetings, and there was the expected high level of community consultation, where the architects could explain the positive impact of the building’s design fully.
Led to higher LEED levels
There are a handful of LEED Platinum buildings in the midwest, says SOM’s Kevin, and WELL is yet to be fully established. The architects benchmarked adjacent buildings, one was WELL certified and LEED Gold, “and that became the minimum to exceed,” with the contract for 800 Fulton Market specifying LEED Gold and WELL Certification. However, as they worked through the design with the client, “it became clear that we needed to aggressively exceed the target, and go for LEED Platinum.”
The client realised this would help them lease space, as “it is what tenants want,” namely verifiable sustainability standards. The biggest driver behind the low carbon design, says Kevin, was operational energy, and it worked with Chicago-based M&E engineer dbHMS, who produced a series of early energy models. They proposed a 50-55% window-wall ratio (“quite low in offices,” says Kevin), and the architects used that as a guide; “We found it drove a lot of things.”
LEED “pushes you away from all glass,” says Rodenkirch, but adds “it’s kind of common sense. All glass buildings tend to be a lot more energy-intensive. Putting some opaque walls in and packing the insulation gives you the most bang for the buck.” He says that in a city with extreme temperature fluctuations like Chicago, a building can’t be dominated by cooling or heating: ”You kind of have to do it all.”
The pragmatic, business-case driven approach to sustainability distinguished the project from some of its more optimistic rivals nearby, who haven’t hit much-trumpeted energy targets, says Rodenkirch. A lot of them went public with their carbon goals, such as Passivhaus and net zero, and very rarely does it happen.”
He says that targeting LEED Platinum also helped broaden the team’s minds: “We could think about the mechanical system in a non-typical way, even the daylighting.” That’s when the design of terraces emerged, “with the ability to set the building back, and gain views.”
Situated broadly at the threshold between a collection of high-rises and much older low-rise brick buildings, the new addition has been designed to bridge the gap, echoing the rhythm and scale of both. The stepped terraces not only provide substantial external space, adding wellness to the building, but also present a softer facade to the nearby low-rises.
Form
The 19-storey tower draws on the area’s industrial heritage, with its brick, steel and glass facades, and striking exposed steel bracing to its east and west elevations. SOM consulting design partner Brian Lee commented: “We set out to design a building that would feel like it had always been part of Fulton Market’s historic industrial character.”
The building gradually steps back, and is ‘backloaded’ towards the north, facing a large glass building across the street (with two more planned). The architects wanted to “preserve the street presence to the south,” so a four storey podium “more or less aligns with the street,” which is mostly in the three to five storey range. The locally-built traditional aluminium curtain wall has opaque ‘shadow box’ sections to the top of the floor-to-floor glass, and infill insulation.
The terraces are around 1200 ft2 and begin at level two, with the outdoor space split into restaurant and amenities, and sitting above a colonnade. The rest of the floors above are offices, with further terraces at levels three and four. There are two other terraces to the north, adjacent to the core.
Structure
In order to free up floor space, the architects decided to push the core to the north of the footprint, a “pretty innovative” move in Chicago, says Kevin. “This gave us the ability to insulate that facade pretty heavily, which is where you want to do it here.” Crucially, the core performed “better as a cantilever” than being the lateral anchor, and enabled a consistent 60 foot span all the way up with no columns, plus the terraces at lower levels.
With no real lateral system, SOM’s structural engineers designed external, high-waisted X-braced frames in steel, which represented a “continuation of the practice’s history of creating structurally expressive architecture.” They are far from mere formal expression, driven by no-nonsense practicality. The glass core of the building is suspended using this highly bespoke structural system, “enabling flexible, light-filled workspaces.”
In order to withstand the extremes of the Windy City’s harsh winters, and hot summers, the frames are designed to contract in cooler weather and expand as the structure warms.
Assisting the sustainability goals, the architects decided not to cover the bracing in aluminium; also it wasn’t required on fireproofing grounds due to being outside the envelope, and simply painted it. However, this exposed steel would be more susceptible to Chicago’s “massive swings in temperature,” says Rodenkirch. Having done something similar at 100 Mount Street in North Sydney, the structural team came up with a thin central hinge plate which “literally bends around 8 inches in each direction,” says Rodenkirch. “You can see in the morning when it’s cold it’s sitting kind of flush, and when it gets warm you see it start to bend out.”
The solution is a highly functional, lean use of steel. Rodenkirch: “I think structural engineers are the original low embodied carbon engineers by design, because everything they have done has been how do you do this in the most efficient design with the least amount of material. Post-tensioned beams were used elsewhere to reduce the structure’s thickness.
Programme
A triple height main lobby with a cantilevered staircase and mezzanine creates “layered spaces of activity.” The internal palette of exposed concrete, wood and red brick echoes the exterior and “draws inspiration from the neighbourhood’s industrial character.” The lobby has flexible, movable seating and informal spaces for working and collaborating, and has been designed to “blend seamlessly into the
busy streetscape.”
The range of amenities (a “big part of the building’s marketing power, in that neighbourhood”) did change during the project. “There are so many offices being built that it almost becomes a kind of amenities race, who can provide more and better.” As well as retail and “community spaces,” the architects added conferencing centres, areas for respite and lounging, and a fitness centre. On level 18, half the floor is a social lounge and game room, and opens up onto the sunset terrace so workers can enjoy a drink at the end of the day.
The terraces have a clear social value, in the months when they are usable, but are an expense that the client has to justify. Rodenkirch says that “tilting the needle” in 2017 was the fact that BOMA (the US standard for buildings measurement), acknowledged that fitted out terraces could be considered rentable. “In theory you could share some of that cost with the tenant,” adds Rodenkirch.
The architects didn’t want excessive amounts of landscape in the spaces, but “enough density so you could read it from the street.” The terraces alternate from standard rectilinear forms in plan to tapering triangular ones, presenting even more variety to the south elevation.
A healthy, smart building
The architects re-evaluated the mechanical systems on a health and safety basis to ensure they were future-proofed post-pandemic. However, says Kevin, “We didn’t make any major changes as the building’s VRF and DOAS ventilation system, somewhat atypical in a Chicago office, uses 100% fresh air.” This ‘mechanical penthouse’ system, which includes some heat recovery, means there’s no recycling of air within the office space.
There are myriad touchless sensors in the building, “which I think we’ll see on every new building going forward,” says Kevin. There’s also a focus on user control, and apps enable access, and control air, light and other parameters, and can be used to reserve amenity spaces such as the fitness suite.
The building is also festooned with smart systems to monitor various conditions and operations and thereby optimise energy efficiency as well as environmental quality for users. The client engaged IT firm Buildings IOT to provide “cloud-based machine learning insights,” while tweaking and optimising fresh air circulation. The building also features electronic charging stations, and scooters for staff or tenants.
Through extensive analysis of the building’s life cycle and a painstaking design approach, the architects managed to reduce the overall structure’s embodied carbon by 65%, compared with an “average commercial office,” thereby meeting the 2030 carbon reduction target set by The American Institute of Architects (AIA).
Rodenkirch says that the seemingly daunting task of attaining both LEED and WELL was made easier by the fact that they overlap in lots of cases. “When you pursue LEED Platinum, you pretty much have WELL certification.” And he adds: “LEED has a lot of points about air quality, which is closely related to WELL.” He says that a lot of aspects are simply good design, but it’s a means of tracking the approaches through a project, and verifying them, while “providing a level of accountability.”
In most US cities, according to Kevin Rodenkirch, architects still need to “fight” to get to the higher levels of energy performance. This was the case in Chicago until recently; he says it’s only in the last two years that the city has “pushed for more aggressive energy codes.” He thinks that this building is a sign of more things to come.