Engineer, architect, creative thinker Ted Zoli. He designed the new Lake Champlain Bridge.
Structural engineer and architect Theodore “Ted” Zoli is recognized as one of America’s brightest designers of beautiful and lasting modern bridges. His creative use of technological advances in the material sciences—for example, developing a composite, blast-resistant material that has a variety of construction applications—has given new promise to the nation’s transportation infrastructure in the post 9/11 world.
Now, Zoli has produced his latest engineering marvel—the exciting, new Lake Champlain Bridge. The new structure, which replaces the demolished 1929 span, links the Crown Point-Chimney Point narrows between Vermont and New York.
But before the celebrated Lake Champlain Bridge project, Zoli made his mark with several notable, and award-winning bridge projects including Boston’s Bunker Hill Bridge, Ohio’s Blennerhassett Island Bridge, and the Missouri River Pedestrian Bridge.
In addition to the art of designing, Zoli has tackled the challenges of engineering science as well—that of armoring several of America’s iconic bridges “to maintain their structural integrity against the possibility of damage from explosion.”
After Sept. 11, 2001, and in a time of budgetary restraints and aging infrastructure, Zoli is developing tomorrow’s designs today to ensure robust, safe, and cost-effective new structures.
Zoli studied at Princeton University and the California Institute of Technology. He is currently affiliated with the HNTB Corporation where he is as a vice president and technical director of bridges. Zoli also lectures at Princeton University’s Department of Civil Engineering and at Columbia University’s Department of Civil Engineering and Engineering Mechanics.
Recently, Zoli became a MacArthur Foundation fellow. A MacArthur fellow is an individual showing exceptional creativity in his or her work with the prospect for still more in the future—Zoli fulfills the MacArthur ideal and more.
We interviewed Zoli about the new Lake Champlain Bridge and how it will impact the region—
How did you become involved in the new Lake Champlain Bridge project?
I grew up in the region—in Schroon Lake, N.Y. I was interested immediately in becoming a part of this project. I grew up knowing the 1929 span very well. My family has deep roots in the transportation infrastructure of the area, too. My grandfather, Theodore Zoli, built the Northway in New York. So, I jumped at the chance to also be apart of a big project in my greater hometown area.
Our Modified Network Tied Arch concept is the basis for the new span. Flatiron Constructors of Longmont, Colo., with the U.S. subsidiary of the German firm Hochtief AG, won the contract for the new bridge. I truly appreciate being involved with such an important project.
When you were asked to submit a bridge design, what governed your creative process leading up to finished drawings?
While it happened all so quickly, I typically spend a fair amount of time thinking about a conceptual design. When I was alone at night, I did a lot of thinking—the look, the use of materials, etc. I even woke myself up from sleeping to work on this design. It was a deep part of my life for many months.
Looking back to the 1929 bridge that so many local residents cherished, what kinds of advances will make this 21st-century bridge a better replacement?
Fay, Spofford & Thorndike Engineers of Burlington, Mass., designed the 1929 bridge. They had to create several techniques—new in 1929—to address specific needs of that span. For instance, he designed continuous bridge trusses without the aid of a computer. This type of truss—a combination of through truss, deck truss, and deck plate girders—is not used very much today, but is was common on early highway bridges.
The 1929 bridge was an important work historically, at least in the field of bridge construction. It survived 80 years which I believe is a good life span for a bridge in that environment.
The new bridge has inclined hangers with multiple intersections that make the network arch structure act like a truss with only axial compressive and tensile forces acting on it. Bending moments and shear forces are very small in network arch structures.
There are several innovations on the new span—flanking “Vs” (supports above the concrete piers), inclined hangers, cross cabling (based on the cross timbers inside an old fashioned covered bridge), load-box girders, the use of thermal spray coating (which isn’t paint, but an application of 85 percent zinc and 15 percent aluminum that is designed for a corrosive maritime environment), and a redundant five-parallel girder approach. (Also, the “modular” arch was built nearby and floated to the span.)
Overall, our modified arch bridge is very safe—it’s state-of-the-art when it comes to structural safety.
Pardon the pun, but what is the lifespan of a modern bridge? 80 years? 100 years?
Bridge lifespans today are between 50 and 75 years. I would say the new Lake Champlain Bridge will last at least 75 years—at a minimum. And because this bridge is vital to the local economy, many of the elements were designed to be replaceable. Repairs won’t impact traffic on the same level as the 1929 truss structure. Cables and decking sections are better designed today; they were created with minimizing traffic delays.
As a bridge engineer-architect, what are your concerns about bridge wear and tear as well as inspection concerns?
The parts of similar modern bridges that require the most frequent inspection are the splash zones, the deck, structural steel components, and the arch. But as a bridge ages, inspections need to be increased. Also, new federal changes to inspection rules require more vigorous inspections. All around bridge safety inspection protocols are evolving and improving. But with less money available, planners and designers need to prioritize rural crossings. We saw how important it is after the demolition of the 1929 bridge. This new bridge is of monumental importance to the region.
What other projects are you working on? What does the future hold—bridgewise?
I am involved with a pedestrian bridge, now under construction, in Dallas, Texas. The bridge spans a city street and had to be designed with a constrained environment in mind—very unlike the Lake Champlain Bridge. The Dallas bridge includes towers and cabling. It’s very interesting visually. Also a pedestrian bridge along the Brooklyn Heights waterfront in New York City. This is a cabled-timber bridge.
In the future, I think bridges will make more use of rigid frames. This is an area worthy of more exploration from a design and material standpoint.