Press-Brake Tub Girder Technology Expands to Multi-Span Applications

Topics: Accelerated, Case Study, Innovation, Press Brake & Folded Plate

Photo Credits: Grand Traverse County Road Commission

Press-brake steel formed tub girder (PBTG) technology consists of cold-bending standard mill plate width and thicknesses to form a trapezoidal box girder, The steel plate can either be weathering steel or galvanized steel, each an economical option.

A concrete or Sandwich Plate System (SPS) deck may be cast-in-place or precast on the girder, making it a single unit. Guardrails are then added, and the structure can be transported by truck to the project site. The unit can usually be installed in one or two days by local crews using their own equipment.

Valmont Structures, a leading providers of infrastructure solutions, manufactures PBTG systems. The Valmont U-Beam™ is a steel bridge beam with a total service life of at least 100 years. The galvanized coating on the beam ensures the first 60 of those years are maintenance-free.

Recently, Valmont Structures installed a multi-span bridge in Michigan using PBTG technology. The following picture are from the installation of the 104’ span bridge. All 12 girders were delivered and installed in a single morning, using a crane from a single location behind the abutment. A cast-in-place deck was set the following week.

Photo Credit: Grand Traverse County Road Commission

Learn more about Press-Brake Tub Girders

For More Information:

Guy Nelson, P.E., S.E.
Business Development Director – North American Structures
Valmont Industries, Inc.
28800 Ida Street
Valley, NE 68064
Tel: 616.813.8514
Email: Guy.Nelson@valmont.com
Website: https://www.valmontstructures.com/products-solutions/traffic-mass-transit/bridge-systems

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→