i-91 rockingham bridges winter construction
NEWS

HDR-Designed Twin I-91 Bridges in Vermont Honored with PCI Design Award

Project’s 100-Year Service Life and Design Innovations Impress

The Rockingham I-91 Bridges in Vermont have been recognized with a Precast Concrete Institute 2021 Design Award. The twin structures were honored in the transportation category as the best bridge with a main span of more than 150 feet.

The PCI Design Awards program, in its 58th year, recognizes design excellence and construction quality using precast concrete. The award is the third year in a row that an HDR transportation project has been honored. Previous winners include the Marc Basnight Bridge in North Carolina and Project Neon in Las Vegas in 2020, and the Gov. Mario M. Cuomo Bridge in New York in 2019.

The bridges in Rockingham take I-91 across the Williams River. They replace two that were built in the 1960s and were showing signs of advanced deterioration. HDR was the design-build engineer of record on the project, responsible for the complete design of the two replacement bridges, the associated road work, maintenance of traffic and coordination of environmental permitting. 

Each bridge is a four-span spliced precast concrete girder structure — a first in Vermont. The Vermont Agency of Transportation had initially prepared a precast concrete balanced cantilever base technical concept. During the proposal phase however, HDR’s team evaluated all applicable bridge solution types and determined that a haunched, spliced precast girder solution was the most efficient and cost-effective.

The spliced design and material choices, such as stainless steel reinforcing in the pier caps and deck, combined to give the bridges a 100-year service life, 25 years longer than standard for other bridges in the area. The bridges, which will be completed in the summer of 2021, also feature massive prestressed concrete beam segments of up to 93 tons, maxing out the lifting capacity at the plant that produced them.

“This award recognizes the innovation and dedication of an amazing team that designed and built this project,” said Thomas French, HDR senior project manager. “These bridges will connect the people of Vermont for the next 100 years, and it’s humbling to realize the part that we will play in so many lives in the coming decades.”