Valmont Press Brake Formed Tub Girder Steel

“Save a Bundle with Tub Girders” – Modern Steel Construction

Topics: Accelerated, Innovation, News, Prefabricated, Press Brake & Folded Plate

Excerpt and images provided by Modern Steel Construction – Save a Bundle with Tub Girders: Press-brake-formed tub girders allow state DOTs to implement bridge bundling programs that do more with less

Gretchen Whitmer became Michigan’s governor in 2018 with a platform that included a pledge to “fix the damn roads.” She and her administration soon learned, though, that a state tax hike would not fund this infrastructure upgrade.

The Michigan legislature voted against an increase in the gas tax, necessitating an innovative and less expensive method for repairing decaying bridges. Their solution: Combine the reconstruction of several bridges into a single contract.

In 2019, the Michigan Department of Transportation (MDOT) launched a design-build pilot “bundling” project called Rebuilding Our Bridges. Preserving, maintaining, rehabilitating, or replacing bridges in groups, referred to as bundling, allows agencies to save time and money by expediting project delivery and reducing design and construction costs.

MDOT bid out the Pilot Design-Build Bridge Bundling project to local contractors in February 2021, and the awarded team of builders and design consultants selected Valmont’s U-BEAM™ galvanized steel press-brake-formed tub girders (PBFTGs).

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Additional Resources

What are Press Brake Tub Girders?

Press-brake-formed tub girder (PBTG) is a new technology for short span bridge applications. It consists of modular galvanized shallow trapezoidal boxes fabricated from cold-bent structural steel plate (watch fabrication video). A concrete deck is recommended to be precast on the girder and the modular unit can be shipped by truck to the bridge site.

The system utilizes standard plate widths (based on availability) and is optimized to achieve maximum structural capacity, with most of the steel in the bottom flange and increased torsional stiffness. It is a closed system, since the girder is closed at the bottom. It is versatile for multiple-deck options.

The system utilizes Accelerated Bridge Construction practices, since it:
- Can be installed in one or two days
- Is modular, allowing the use of a precast deck
- Is cost-effective―as much as 1/3 less than a standard concrete girder structure
- Is simple to fabricate, requiring very little welding.
The Short Span Steel Bridge Alliance has developed standardized plans using standard plate sizes (60”, 72” 84”, 96”, 108”, 120”). The designs were developed to achieve maximum structural capacity and are available to use in the free-to-use, web-based design tool eSPAN140.

The press-brake-formed tub girder system is open source.

Learn more about press brake tub girders→