Before he led the structural design on such groundbreaking tall buildings as the Torre Cepsa in Madrid and the World Trade Center in Abu Dhabi, Robert Halvorson studied structural engineering at Cornell and Stanford, and he began to love the challenge of making the impossible possible.

“In school I was taught that design really isn’t a search for freedom,” Halvorson says. “It’s a search for constraints, which is really true. If you don’t have any constraints, you don’t know where to start. There’s no right answer, but if you have a bunch of constraints, like a challenge to solve, then you can think about creative ways to solve that challenge or overcome that challenge.”

More than 40 years later, Halvorson’s work at Skidmore, Owings & Merrill (SOM), at his own firm Halvorson and Partners and finally at WSP, where he is executive vice president and global leader of building structures, has met and overcome those challenges of constraint and left a record that has pushed structural engineering forward in the 21st century and earned him ENR Midwest’s 2021 Legacy Award. In 2019, Halvorson entered semiretirement at WSP, although he still works with several longtime clients and advises other structural engineers at the firm.

Halvorson has been recognized as a fellow of both the American Society of Civil Engineers and the Institution of Structural Engineers in the U.K. In 2016, IStructE honored Halvorson with its Gold Medal, elevating him to an elite club of structural engineering greats that includes Ove Arup, Santiago Calatrava and Edmund Happold.

Young Engineer

Halvorson began his career at SOM in 1976 and worked in the firm’s Chicago, Houston, New York and London offices. He became SOM’s youngest partner at the age of 31 in 1983, and that same year, Halvorson and fellow engineer Michael Fletcher spent the night of Hurricane Alicia on the Allied Bank Center’s [now the Wells Fargo Center] unfinished top floor, just to see how much the building would sway and if it fit into the design calculations they made for the 71-story tower. The design passed the test. Halvorson is quick to point out that his quick rise at SOM would not have been possible without the mentoring in which the firm takes pride.

“There were a handful of guys there at the time, Hal Iyengar and Stan Korista, who have both now sadly passed away, and some others that spent a lot of time with me and watched me make mistakes and correct them, and those men I owe a lot to,” Halvorson says, “All of us sort of go through that process, but it’s really not so much a formal process. It’s really just spending a lot of hours working on projects together. I spent a lot of time with Hal Iyengar when I worked with them. He was a good friend and just a brilliant, incredible guy. He could get right to the heart of any issue that came up.”

One of Halvorson’s last projects in the Houston office was a tower project where SOM’s architect partners recommended they go to Chicago and receive input from Willis Tower engineer and architect Fazlur Khan.

Striking Out on His Own

By 1996, Halvorson was ready to start his own firm and founded Halvorson and Partners with a few engineers that decided to come with him.

“The market was really not good at the time,” he says. “I sort of felt I had traveled around the world, started in Chicago, Houston, New York, then London and finally wound up back in Chicago.”

The one thing Halvorson’s firm had going for it was that there were a lot of former SOM architectural partners out there who had left and started their own Chicago firms and were looking to hire structural engineers.

“Our first clients actually were my former partners,” he says. “Lucien LaGrange, Jim DeStefano and others, they actually supported us and got us going.”

As the small firm grew from one computer, one cabinet and one table, more small projects continued to come in. Halvorson and Partners was brought in for a Chicago skyscraper project that was being planned by the Pritzker family, owners of the Hyatt Hotel chain. The development was scrapped due to economic uncertainty after the 9/11 terrorist attacks, but the architect that Halvorson and Partners worked with on the project was Foster and Partners, and that led to a longtime collaboration between Lord Norman Foster and Halvorson.

“Foster called back and had a project in Madrid [the 815-ft-tall Torre Cepsa] and asked if I could help them with it, so that was sort of the start of a very long and productive collaboration with Foster and Partners. It really, really was, professionally, a wonderful, wonderful thing,” Halvorson recalls.

Using two external reinforced concrete cores to provide lateral and vertical support for the entire tower was a solution that evolved from an iterative architectural and structural design process with the goal to create valuable unobstructed views and a dramatic column-free ground floor lobby. Another project with Foster + Partners was the Index Tower in Dubai.

As the firm grew, so did the number of young engineers that Halvorson mentored. One of them was Eric Fenske, who joined the firm immediately after graduating from the University of Minnesota. Over a career at Halvorson and Partners, Thornton Tomasetti and at DeSimone Consulting Engineers, where he’s now associate principal, Fenske has been a lead engineer on significant projects in all corners of the globe, serving as senior project engineer on the World Trade Center in Abu Dhabi, for example.

“Being at a firm of that size and being able to be a big part of some very big jobs was an amazing opportunity at that time in my career,” Fenske says.

Elder Statesman of the Profession

As the firm grew to 40 engineers and other employees, it was acquired by WSP in 2015. Halvorson was an instrumental member of WSP’s leadership, growing the global building structures practice while continuing to deliver clever structural engineering designs that, as one client put it when describing the Hanking Center in Shenzhen, China, “make magic.”

“There’ve been a number of people like Eric who I’ve really enjoyed working with, bright guys who, yeah, maybe I helped them a bit,” Halvorson says, “but they came up with ideas that I never would have thought of. Isn’t that how Socrates did it—the students and the teacher would argue and talk and learn from one another?”

Halvorson still works on select projects for clients at WSP and is excited about where technology has moved the profession and how engineering problems are not the daunting tasks of the past. “Even our ability to analyze these things quickly and without too much pain,” he says. “The tools and the technology really have come of age over the last couple of decades.”