INDOT has discovered the next big thing in bridge building: NEXT beams.
NEXT stands for Northeast Extreme Tee, a beam cross section developed by Precast/Prestressed Concrete Institute Northeast as an alternative to adjacent box beams.
“Box beams have their limitations: a two-phased pouring process, durability concerns, and closed cells that make inspection difficult,” said INDOT Bridge Design Manager Pete White. “NEXT beams feature a single-pour production that includes the top flange to reduce offsite fabrication and onsite installation costs. They are easier to inspect because they are visible underneath. They also work well for accelerated bridge construction (ABC).”
ABC is the practice of offsite bridge fabrication so that installation goes quickly, often within 48 to 72 hours.
NEXT beams are 8 to 12 feet wide with typical span range of 20 to 80 feet. They are often used as an alternate to adjacent box beams, but since they’re wider, each NEXT Beam takes the place of at least two adjacent box beams.
INDOT is using NEXT beams in three pilot projects:
· Clark County: U.S. 31 over Blue Lick Creek (prefabricated sections put in place August 2023)
· Fountain County: State Road 341 over Dry Run (prefabricated sections put in place October 2023)
· Porter County: State Road 49 over Ahlgrim Ditch (November 2023 project letting with prefabricated sections expected to be put in place in 2024)
“The three pilot projects are to demonstrate the applications of these new beam shapes as an additional alternative for short- to mid-span bridges across the state,” said White.
INDOT Seymour District Capital Program Management Director Chris Wahlman witnessed the installation of the U.S. 31 NEXT beams.
“In the span of just a couple of hours, the beams were put in place,” said Wahlman. “The process was incredibly concise and accurate and used classic ABC principles.”
Said Seymour District Project Manager Greg Prince: “It was exciting to be part of this innovative and unique pilot project. I appreciate the tremendous coordination from so many to help make this project a success.”