Research Reports: Development and Experimental Testing of Press Brake Tub Girders

Topics: Accelerated, Innovation, Press Brake & Folded Plate, Research

Press brake steel formed tub girder 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. Once the plate has been press-brake-formed, shear studs are then welded to the top flanges. A reinforced concrete deck is then cast on the girder in the fabrication shop and allowed to cure, becoming a composite modular unit. The composite tub girder is then shipped to the bridge site, allowing for accelerated construction and reduced traffic interruptions.

The Short Span Steel Bridge Alliance developed standardized plans using standard plate sizes (60”, 72” 84”, 96”, 108”, 120”). The designs were developed to achieve maximum structural capacity.

The complete research report is provided in seven volumes and is available for free download:

Volume I – Development and Feasibility Assessment of Shallow Press-Brake-Formed Steel Tub Girders for Short Span Bridge Applications – Barth/Michaelson

Volume II – Experimental Evaluation of Non-Composite Shallow Press-Brake-Formed Steel Tub Girders – Barth/Michaelson/Kelly

Volume III – Evaluation of Modular Press-Brake-Formed Tub Girders With UHPC Joints – Barth/Michaelson/Kozhokin

Volume IV – Field Performance Assessment of Press-Brake-Formed Steel Tub Girder Superstructures – Barth/Michaelson/Gibbs

Volume V – Fatigue Performance of Uncoated and Galvanized Composite Press-Brake-Formed Tub Girders – Barth/Michaelson/Tennant

Volume VI – Field Performance and Rating Evaluation of a Modular Press-Brake-Formed Steel Tub Girder With a Steel Sandwich Plate Deck – Barth/Michaelson/Tennant

Volume VII – Field Evaluation of Modular Press-Brake-Formed Steel Tub Girder in an Application that Includes Skew and Superelevation – Barth/Michaelson/Tennant/Roh

Volume VIII – Development and Validation of Live Load Distribution Factors for Moment in Press-Brake-Formed Steel Tub Girder Bridges – Barth/Michaelson/Woldegabriel

Download the Full Report (6 MB)

Volume IX – The Impact of Skew on the Ultimate Capacity of Press-Brake-Formed Tub Girders – Barth/Michaelson/Morgan

Download the Full Report (4 MB)

Testing for the press brake tub girder was completed at West Virginia University.

For More Information:

Karl E. Barth, Ph.D.
Co-Leader, SSSBA Bridge Technology Center
Jack H. Samples Distinguished Professor at West Virginia University
Email: Karl.Barth@mail.wvu.edu

Gregory K. Michaelson, Ph.D., P.E.
Co-Leader, SSSBA Bridge Technology Center
Assistant Professor, Department of Civil Engineering at Marshall University
Email: michaelson@marshall.edu

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→