As a child, civil engineer and MIT Morningside Institute for Design (MAD) fellow Zane Shemer marveled at the grandeur of San Francisco’s Golden Gate Bridge, but he’s always been fascinated by bridges — what they look like, why they serve a purpose, and how they are designed and built.
While preparing for college, he considered choosing between architecture and engineering, but found himself intrigued by the why and how of structural engineering and chose the latter. He now approaches design as an iterative process of writing algorithms that perfectly balance the forces involved in each individual part of a structure, creating an overall design that optimizes function, minimizes carbon emissions, and still produces a manufacturable outcome.
This may seem like an obvious goal in structural design, but it’s not. It’s new. It’s a more holistic view of the design process that can optimize materials, angles, and even the number of components within the nodes or joints that connect larger components like buildings, bridges, and towers.
Schemer says there hasn’t been much progress in optimizing structural designs to minimize embedded carbon, and current research often results in designs that are “too complex to realistically build.” Embedded carbon in a building is the total amount of carbon dioxide emitted throughout a building’s life cycle, from the extraction or production of materials to transportation, use, and then the building’s demolition and disposal of materials. Working with Josephine V. Carstensen, the Gilbert W. Winslow Career Development Associate Professor of Civil and Environmental Engineering at MIT, Schemer focuses on the part of the cycle that takes place during construction.
In September, at the IASS 2024 conference “Redefining Structural Design Technology” in Zurich, Schemer and Carstensen presented their work on a discrete structural optimization algorithm that could reduce the embodied carbon footprint of bridges and other structures by up to 20 percent by selecting materials based not only on their appearance and ability to work, but also on their affordability, proximity to the construction site and the carbon footprint of their manufacture and transportation.
“The real novelty of our algorithm is that it can generate manufacturable designs that consider multiple materials in a highly constrained solution space and have user-specified force flows,” says Schemer. “Real-world problems are complex and often come with many constraints. In traditional formulations, it’s difficult to have a long list of complex constraints. Our goal is to take these constraints and make the design easier to take out of the computer and make in the real world.”
Steel towers, for example, can be “an ultra-lightweight, efficient design solution,” Schemmer explains. Because steel is so strong, you don’t need as much steel to build a large building as you do with concrete or wood. But steel is very carbon intensive to produce and transport. Shipping steel domestically, especially from other continents, can dramatically increase the carbon price of the steel. Schemmer’s structural optimization involves replacing some steel with wood components and reducing the amount of steel in other components, creating hybrid structures that are functionally efficient and have a reduced carbon footprint. “This is why using the same steel in two different parts of the world results in two optimized designs,” he explains.
Schemer, who grew up in the mountains of Utah, earned bachelor’s and master’s degrees in civil and environmental engineering, including graduate studies in seismic design, from the University of California, Berkeley. He said his education provided him with “a very traditional, very strong engineering background that has solved some of the toughest engineering problems,” along with knowledge of structural engineering traditions and current methods.
But a lot of the research he sees at MIT “removes the constraints of current societal conventions about how things should be done and asks, how could we do things in a more ideal way, and what are we looking at? And I think that’s really great,” he says. “But I also think that sometimes there’s a big gap between the most perfect version of something and where it is now, and we need to build a bridge between the two. And I feel like my education allows me to understand that bridge.”
The bridge he is referring to is a structural optimization algorithm that allows for better designs that can reduce the potential for global warming.
“That’s where optimization algorithms come in,” says Shemer. “Unlike standard structures designed in the past, this algorithm can use the same design space and come up with a much more efficient use of materials, while still meeting all the structural requirements, complying with regulations, and having everything we want in terms of safety.”
That’s where the MAD Design Scholarship comes in. The program offers graduate students from across the Institute one-year fellowships and full financial support, facilitating interactions with each other, MAD faculty, and external lecturers who leverage design in new ways across an incredible variety of disciplines, helping students better understand how to use iterative design in their own work.
“Typically, people think about their work in terms of, ‘Oh, I have this background,'” Shemar said. “I’ve been thinking like this for a long time. And then when you look at it from an outside perspective, you’re like, ‘Oh my gosh. I never thought I’d do it that way. Maybe I should give it a try. That can move you on to new ideas and inspiration to do your job better.”
He chose civil and structural engineering over architecture about seven years ago, but says, “I don’t think 100 years ago architecture and structural engineering were separate professions. I think they were fused together, with an understanding of how things looked and how they worked. Maybe it was more efficient than doing them separately. But now that I understand how the whole system works and can weave more of the freedom of architectural design with the mathematical design of a civil engineer, I think it makes sense. I think there are a lot of benefits to fusing them together.”
Which brings us back to a bridge that Shemar has loved for years: the Golden Gate Bridge. I can still hear the excitement in his three-year-old boy’s voice as he talks about it.
“It’s so iconic,” he said. “It connects two pieces of land that jut straight out of the ocean. There was fog coming in and out for days. The size of the cable and everything, it’s a really magical place. All I can say is, ‘Amazing.’ People built this place over 100 years ago, before we had a lot of the computing tools that we have today. So all the calculations, all of the design, are done by hand, in your head. It’s crazy to think about it, because nothing is computerized.”
As Shemer continues to pursue his doctorate at MIT, his MAD fellowship will give him exposure to great ideas from other fields, allowing him to somehow combine some of those ideas with his own engineering knowledge to design better ways to build bridges and other structures.
