Extreme Engineer of the Month

Profile: Kieran Kelly-Sneed, Architectural Engineer
Advanced Structures, Inc.

Kieran had always been interested in architecture, but he was good in math as well. So he set his sights on a college program that would combine the best of architecture and engineering. He knew he definitely wanted to be involved in designing buildings. He first looked for architecture schools that also had strong engineering schools, but didn't find any that allowed him to combine the two. Then he discovered the field of architectural engineering and the program at Cal Poly San Luis Obispo—the California Polytechnic State University.

To graduate from the program, students are required to do a senior project. CalPoly gives students the opportunity to build large-scale structures. The school has a 13-acre outdoor laboratory where students are encouraged to build things full scale. For his project, Kieran assembled a team to build a tensile structure, using essentially the same materials as the Denver International Airport. "I saw this as a very clear expression of engineering in architectural form," Kieran said. "That strikes at the very heart of what architectural engineering can be in the way that it blends the two fields. That combination of form and function and expression of an architectural aesthetic is one of the reasons that architectural engineering is the field for me."

As Kieran explained, tensile structures are defined by picking a series of points. In this case it was six perimeter points and one central point that all varied in elevation. For any given set of boundary edges or points, there is typically one surface that will cover them. He says you can model that with a soap film, for instance, if you bend up a wire frame in a zigzag pattern, you get a soap film that takes the same sort of tent shape. That surface is called a minimal surface, he explained. In it, the stress in any direction—or every direction—is uniform. "It's a pure engineering or architectural shape—and also a natural shape," he said. A lot of early work on structures such as that drew heavily on inspiration from nature for ideas about how these structures should be shaped. Advanced Structures, Inc. (ASI) provided Kieran some computer modeling help and access to software to identify the minimal surface that fits the points that he wanted to use. ASI was impressed with his project and hired him after graduation.

The first project Kieran worked on for ASI was the new civic center for San Jose, CA, which just opened in October 2005. It was designed by internationally known architect Richard Meier, who also designed the Getty Center in Los Angeles. Kieran says that is one of the exciting things about his job—having the opportunity to work with cutting-edge architects on impressive structures.

The portion of the civic center Kieran worked on was the large glass dome, which is about 110 feet tall and 90 feet in diameter and rests on a cylinder. The design translates a traditional Federalist style rotunda into a modern structure in character with Silicon Valley. The dome is covered by 5 ft. by 5 ft. and 5 ft. by 10 ft. tempered, laminated glass with stainless steel trusses and aluminum cladding to create an unusual, but magnificent structure. Kieran and his colleagues at ASI worked on the glass cladding system, which is supported by a system of cable trusses.

The architectural engineering team applied cable trusses to the dome structure with one-half inch cables running horizontally and vertically behind the glass. The trusses have four-point arms mounted to them and the arms connect to the glass. The result is that there is no visible supporting structure for the most part on a 25-foot wide by 100 foot tall span. Implementing this advanced architectural concept required a heavy dose of engineering.

Kieran spent about a month and a half in the field working with the contractor to erect the structure. “The cable system is difficult technology to understand and one needs an intuitive sense of how it behaves,” says Kieran. “It’s not something that most contractors have experience working with. It requires a lot of support.” On site Kieran conducted tests to ensure that the system performance matched what the computer modeling and analysis had predicted. “That’s where the engineering comes in,” says Kieran, “identifying and solving problems. There is always something that is not quite as expected in the field. The object is to identify the problem, its source, and how to fix it. As an engineer, that’s something I love doing.”

Working for a consulting company, Kieran works on small portions of many large buildings—and often on the most interesting and complicated portions of those structures. The company often begins working on a project with preliminary consulting to help refine the initial design and make sure it’s practical to build. The company has worked on a lot of airports, institutional buildings such as the Securities and Exchange Commission Building in Washington, D.C., museums including the new Newseum, government buildings, and libraries, including Clinton Library in Little Rock, Arkansas.