MARCH 30 2022
The I-91 Interchange 29 Exit Ramp Flyover Bridge in Hartford, Conn., is the 2022 Bridge of the Year!
The National Steel Bridge Alliance and participants of last week’s World Steel Bridge Symposium in Denver selected the 880-ft. bridge for the top honor in NSBA’s Prize Bridge Awards program. This is the first year NSBA has presented the Bridge of the Year Award.
“It’s fitting that the inaugural Bridge of the Year Award goes to a first-of-its-kind project,” said NSBA Senior Director of Market Development Jeff Carlson. “The I-91 Interchange 29 Exit Ramp Flyover Bridge marks the beginning of a new approach to eliminating fracture critical elements by providing load path redundancy–one that has already made an impact beyond Connecticut’s borders.”
The I-91 Interchange 29 Exit Ramp Flyover Bridge is the centerpiece of a recent project to reduce daily congestion. The interchange now features a two-lane, high-speed ramp that showcases a novel approach: a triple I-girder straddle bent that provides load path redundancy, eliminating fracture-critical designations and the associated long-term inspection costs.
“The triple I-girder straddle bent cap is a highly innovative and very effective solution,” said Prize Bridge Award Judge Domenic Coletti, PE, principal bridge engineer at HDR. “It took advantage of steel’s benefits all around.” The DOTs in Texas and Georgia, which both typically rely on concrete straddle bents, are closely examining this steel alternative.
An additional benefit became clear during fabrication: The triple I-girder configuration is surprisingly economical to fabricate, costing substantially less than a comparable box girder with reduced shipping costs, as well. The team found even more economy by choosing uncoated weathering steel, in which a patina protects the structural steel from corrosion. The Connecticut Department of Transportation has used uncoated weathering steel since the early 1960s, and some of the oldest bridges are still in very good condition after more than 55 years of service.
The American Institute of Steel Construction and National Steel Bridge Alliance have recognized outstanding bridge design since 1928. Eight bridges won Prize Bridge Awards in the 2022 competition. NSBA will accept entries for the 2024 competition in the spring of 2023.
Completed project image by CDOT and O&G/BHD
Detail image by CHA Consulting