Perhaps the most famous architect and engineering duo of the late 20th century, Bruce Graham and Fazlur Kahn revolutionized high-rise design through structural expressionism, the idea that a building’s structure should be intuitively legible and integrated with its aesthetics. Their work coincided with the dawn of Modernism—an approach that fundamentally combined formal and aesthetic qualities with functional performance.
Kahn and Graham founded SOM, a firm that continues to push architecture forward. Ryan Culligan, an architect design partner at SOM, says that the pair’s wildly successfully collaborations were the product of their humility and clarity. For example, their 100-story, 1,200-foot John Hancock Center in Chicago is derived from two ideas: structural expression through its signature X-brace trusses, which distribute the vertical (gravity) loads and lateral (wind) loads across the building’s structure, and the variety of mixed-use programs and activities that have made it a hub of urban vitality in Chicago since it opened in 1970. “The designers behind that building were sensible enough to not try to upstage these very clear ideas,” Culligan says.
For Khan, this sort of artist vs. engineer collaboration was the next best thing to realizing the pre-Modern master-builder tradition, which was shattered by the specialization and professionalization of building trades. That’s a tide that’s not likely to recede anytime soon, and the need for collaboration with engineers still guides Culligan’s work today.
“We talk about that a lot in our current work,” Culligan says. “How do we allow for, in a humble way, a really strong idea that might not have originated in architecture to be amplified through the architectural expression?” Understanding the differences between architects and engineers and putting workflow structures in place that allow—or require—effective communication creates a strong foundation for any building project.
Aside from builders, architects and engineers are the two most visible professions in the construction industry, and their skills are entirely complementary. In general, architects are responsible for the overall design of buildings while engineers are viewed as technicians who help enact this vision. However, the most progressive and successful collaborations between the two significantly blur this boundary.
Clients hire architects to design buildings at a wide range of scales—from a single house to an entire neighborhood. It’s their job to holistically consider the building and to define its conceptual direction. These designers are responsible for all the broadly defined elements of the building and how it interacts with its immediate context. This includes helping clients determine the program of the building (what activities will take place in it and how it will function), its form and shape, its interior environments, and the materials that will be used.
This wide purview means that architects are sometimes less focused on technical details. However, architects are increasingly concerned with ensuring that their buildings run efficiently and sustainably—with as little energy as possible—and these criteria often require intense technical management.
In the United States, the standard professional architecture degree is the Bachelor of Architecture (BArch), which often takes five years to complete. Some architecture firms see the next professional degree, a two-year Master of Architecture (MArch), as the preferred professional level. PhD programs for architecture are available but are typically for people who want to work in academic or research settings instead of professional practice.
The American Institute of Architects (AIA) is the largest professional association serving architects in United States. To be solely responsible for a building project, architects must be licensed, which requires passing a series of exams. In general, it’s more common for clients to hire architects as their primary consultant, with engineers as subconsultants.
If architects are typically responsible for the what of a building, engineers handle the extremely important how. Traditionally, engineers focus on the technical execution of the architect’s plan: How to balance material economy and expense to achieve a design plan’s functional goals and aesthetics. This emphasizes quantitative skills such as science and math over qualitative ones such as artistic composition and balance. In a building, engineers might be responsible for any of the structure’s mechanical systems and hidden infrastructure (wastewater, HVAC, electrical systems, and so forth).
The most common engineers that architects work with are civil engineers—who focus on public infrastructure such as airports, bridges, and roads—and structural engineers, who specialize in the structural systems for buildings and other construction projects. Any number of engineering specialties can be relevant to architectural collaboration, depending on the project: geotechnical engineers for underground projects, transportation engineering for transit buildings, environmental engineering for green infrastructure, and so on. Some architectural engineers even specialize in working with architects or work in-house alongside them.
Undergraduate professional engineering degrees (Bachelor of Engineering degrees) tend to take four years, and engineering master’s degrees take two years. Similar to architecture, PhDs in engineering generally focus on research and academia. There are more subfields of engineering degrees than architecture; new graduates might specialize in mechanical engineering, structural engineering, chemical engineering, civil engineering, electrical engineering, or material engineering—just to name a few.
Being an engineer also requires licensure in accordance with state laws. Several professional associations serve engineers; two of the most prominent are the American Society of Civil Engineers (ASCE) and the National Society of Professional Engineers (NSPE). Typically, engineers are subconsultants to architects.
The public-facing visibility of a project can be a clue to whether it needs an architect, engineer, or both. For example, repairing or installing new sewer utilities calls for an engineer while designing an office building requires an architect. However, any public-facing project of even moderate sophistication will require both roles. A new building design that is novel or rare in any substantive way will benefit from the perspective of both professions—as will repair, renovation, or reuse projects for particularly degraded properties.
Traditionally, architects and engineers work together in what’s called the design-bid-build process, a model that’s slowly being discarded in favor of more collaborative, less hierarchical arrangements. In design-bid-build, an architect designs a building in relative isolation, then hands it over to an engineer to essentially troubleshoot, fixing errors and inefficiencies in the structural systems. Next, the project is put out to bid for contractors to estimate how much they would charge for the job. Finally, the project is built.
The relationship between the architect and engineer shifts as the process moves along. Early on, when architects are formulating design concepts, engineers take on consultant-like roles, checking the architect’s work to make sure it’s viable. As construction nears and finally begins, engineers become more central, managing and coordinating execution. Often, each of these phases happens separately, with limited communication between disciplines and a discrete “baton handoff” from one profession to the other; each discipline’s responsibilities are narrowly tailored to limit liability.
More collaborative approaches between architects and engineers are emerging that fundamentally question the way cross-disciplinary teams work together. For instance, integrated project delivery (IPD) means that at the outset of a project, architects, engineers, project managers, clients, and contractors sign a joint contract that outlines shared risk and involvement across the entire design and construction process. This establishes communication protocols and workflow processes that ensure the entire team is aware of what’s happening on a project at any given time, providing a higher and more participatory level of quality control.
This practical approach can be enhanced with digital tools such as building information modeling (BIM) that provide a shared, manipulatable model for all parties. “It alleviates some of the traditional challenges associated with having the architect ‘in charge’ of all the consultants on the project,” says Clare Olsen, an assistant professor of architecture at Cal Poly San Luis Obispo and co-author of the book Collaborations in Architecture and Engineering (Routledge, 2014) with engineer Sinéad Mac Namara. “With an integrated project, the major players are contracted to work together as a team from the beginning.”
“The relationship allows for buy-in on the design concept from all parties earlier on, which means that people have more at stake in terms of getting it done well,” says SOM’s Culligan. “It’s not enough for an architect to hand engineers a design quandary they devised, then ask for the engineer to adopt a ‘problem-solving approach.’” Ideally, engineers have a hand in creating the design challenge to be solved.
When this doesn’t happen, catastrophic structural failure can result, but the most common negative outcomes are cost overruns, lost time, and wasted carbon emissions. Another potential result is “spaces that are not tuned to climate and comfort,” Culligan says, referring to the way gaps in the design and building process can create buildings that are too hot, cold, or drafty. Similarly, he says, a strained architect-engineer relationship is likely to create spaces that are not flexible enough to accommodate the inevitable changes in building use over its decades-long lifespan.
In the book Collaborations in Architecture and Engineering, Olsen and Mac Namara asked architects and engineers to rank the most important criteria in hiring employees. Surprisingly, design talent and skill didn’t make the top of the list. Instead, the most desirable quality was “the ability to collaborate.”
BIM is one tool among many that architects and engineers can use to encourage better collaboration across disciplines. The BIM process lets professionals access more detailed information about buildings at various stages before, during, and after construction; 3D-design software such as Autodesk Revit can help designers and engineers make sound decisions early on, saving time and money by preventing issues later. “It’s really about the way BIM allows for collaboration in the process of designing buildings and enables more efficient construction of them,” Olsen says.
With near-instantaneous shared access to a digital model, design team members can be much more iterative across disciplines, Culligan says. For example, in the space of a week, they can swap out different HVAC systems to see how climate thresholds and spatial qualities are affected. “We’re able to make decisions so much faster than we used to be able to,” he says.
Beyond this sort of technical deep-knowledge, BIM’s ability to aid communication and transparency are key. “Transparency is a very important thing to have on any project; it enables us to see what others are doing or planning to do,” says Paul McGilly of engineering firm Buro Happold, which has been working with Revit since 2005. The firm has developed in-house computational tools to help identify detailed design changes (and their ramifications) that are made in a design partner’s BIM model. “It’s a lot for us to ask an architect to outline all the changes,” McGilly says. “They might give us a broad overview by email. I just don’t think that’s a sufficient way of communicating changes on multimillion-square-foot projects, where we are faced with tighter, more demanding project deadlines.”
At SOM, nearly all projects begin by inviting in leads from each discipline to talk through design concepts, review building contexts, and agree on the proposed program. Teams will sketch and diagram, putting together a loose charrette. “We’ll ask for each of the different disciplines to come with some homework prepared where they bring three ideas that they think might be special for this project,” Culligan says. “In my experience, a few of these ideas, or one, rise to the surface really quickly.”
Most important, in this setting, a winning idea can arise from any discipline—architecture or beyond. Inviting all building and construction disciplines to the table at an early stage is essentially opening up the holistic design of the building to all team members—a spotlight that some architects can be sensitive about sharing.
Designed by Killa Design and engineered by Burro Happold, the museum is a torus-shaped teardrop with a void at its center with structural gymnastics to spare, but its most complex element might be its facade. Covered in windows shaped like delicate Arabic calligraphy, the building’s facade is made up of 1,240 unique, jointless stainless steel and fiberglass–fused panels. The entire design process from initial conceptualization beyond construction documents was completed in Revit.
The O-14 tower turns architecture’s typical ideas of structure and ornamentation inside out. The building by architecture firm Reiser+Umemoto advances Graham and Kahn’s ideas of structural expressionism, but instead of presenting the structural elements of a high-rise as discrete facade elements in a larger composition, O-14 makes the entire primary exterior facade its source of structural strength and its main aesthetic experience, all while completely separating it from the habitable floor plates of the building. With structural engineering firm Ysrael A. Seinuk and mechanical engineering from ARUP, the fluid honeycomb concrete shell is clearly what’s keeping the building upright, yet its pattern of circular voids is a purely architectural encounter.
From three 55-story towers, split and splayed into six legs, this resort by Safdie Architects and ARUP hoists a 1,000-foot-long “SkyPark” 656 feet into the air, a lushly landscaped place to drink, dine, mingle, and swim to the edge of an infinity pool looking out over Singapore’s skyline. Like a sleek cruise ship bridging these towers, the SkyPark hull was made offsite and transported in 14 steel segments, eventually lifted into place with hydraulic stand jacks over the resort’s hotel, convention center, casino, retail spaces, nightclubs, event plaza, and museum. The SkyPark features one of the longest cantilevers in the world, at 232 feet (the length of a 747 jet), into which is stowed a 5-ton mass dampener to aid stability.
Often, the most impressive feats of architectural engineering happen far from where they can be seen. That’s the case with New York City’s Hudson Yards, a tabula-rasa skyscraper district on Manhattan’s West Side. Its high-rises (by KPF, Diller Scofido+Renfro, Rockwell Group, and SOM) sit atop a web of utilities and dozens of active rail lines that were active during construction, which meant that less than half of the site could have structural supports inserted.
Led by Thornton Tomasetti (the structural engineer) and Langan (the environmental and geotechnical engineer) the 18-million-square-foot development is built on a platform 30-plus feet above the train tracks, much of it made from precast concrete slabs and structural steel. That’s 25,000 tons of structural steel for just one section, the Eastern Yard, held aloft by 288 caissons, ranging from 4 to 5 feet in diameter, reaching 20 to 80 feet in depth drilled to reach bedrock. Inside this vast structural assembly is a network of cooling liquid tubes that moderate the scalding-hot temperatures (up to 150 degrees) in the train yard to give the plantings up top designed by landscape architecture firm Nelson Byrd Woltz a chance to thrive.
SOM’s office tower for a Chinese conglomerate is the latest evolution of the structural expressionist cross-bracing system Kahn and Graham deployed at the John Hancock Center. The 31-story skyscraper uses an interior concrete core and an exterior diagrid system: a diagonal diamond-hatch pattern of exterior structural steel that shares vertical gravity and lateral wind loads ultra-efficiently. This muscular and dramatic exoskeleton (made of steel tubes filled with concrete and clad in white aluminum) wraps about the building’s curved facade, even while each structural member is ramrod straight. By locating all of the structural supports at the extreme perimeter of the building, the architects and engineers at SOM created a sheath-like system that allows for endless expanses of glass, column-free interiors, and two 400-foot atriums that nearly reach the very top of the tower.
This article has been updated. It was originally published in July 2015.
Zach Mortice is an architectural journalist based in Chicago.
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