PBTG bridges may be a quicker, more cost effective solution for short-span projects

Updated Aug 4, 2018
St. Clair County, Michigan, workers reduced installation time when they replaced a 70-year-old severely deteriorated steel superstructures with a new press-brake-formed steel bridge superstructure in 2017.St. Clair County, Michigan, workers reduced installation time when they replaced a 70-year-old severely deteriorated steel superstructures with a new press-brake-formed steel bridge superstructure in 2017.

For bridge builders and owners, there’s growing interest in an innovative bridge system for replacing structures with spans of up to 60 feet.

The Short Span Steel Bridge Alliance (SSSBA) has published the results of extensive research on the development and experimental testing of an innovative bridge system designed by members of the organization and several partners.

“Press-brake-formed steel (PBTG) tub girder bridges are an excellent solution for replacing structures with spans of up to 60 feet because they are cost-effective, remain in service for up to 100 years with proper maintenance, and can be installed in less time than some other types of bridges, minimizing traffic delays,” explains Rich Tavoletti, director of the Short Span Steel Bridge Alliance.

One such example of saving time and money came in St. Clair County, Michigan, in 2017, when the St. Clair County Road Commission (SCRC) chose to replace two 70-year-old severely deteriorated steel superstructures with a new press-brake-formed steel bridge superstructure, the alliance says.

Those on the project saved time in St. Clair County, Michigan, with press-brake-formed steel tub girders.

The existing bridges had carried traffic on the Marine City Highway, a two-lane road that handles more than 10,000 vehicles per day. It’s the main thoroughfare into and out of Marine City, Michigan, for commercial and school traffic.

The two bridges involved a 25-foot-span steel beam bridge and a 35-foot-span steel beam bridge on a 45-degree skew.

The alliance provides an overview of this project on its website as one example of the advantages of using press-brake-formed steel.

“These and other benefits are generating interest from bridge owners, engineers and other design professionals who are looking for solutions to their own bridge infrastructure challenges,” Tavoletti says.

“We published the research to answer many of their questions and are making it easily accessible for wider distribution. We anticipate PBTG bridges will become a common solution for federal, state and local jurisdictions that need to replace many bridges quickly and economically.”

The research, “Development and Experimental Testing of Press-Brake-Formed Steel Tub Girders (PBTG) for Short Span Bridge Applications” was compiled by Karl Barth, Ph.D., the Jack H. Samples Distinguished Professor of Structural Engineering – Civil and Environmental Engineering at West Virginia University; and former research assistant Greg Michaelson, Ph.D., P.E., now Assistant Professor of Civil Engineering at Marshall University.

“Development and Experimental Testing of Press-Brake-Formed Steel Tub Girders for Short Span Bridge Applications” consists of five volumes that are available for free download here. They include:

  • Volume I – “Development and Feasibility Assessment of Shallow Press-Brake-Formed Steel Tub Girders for Short Span Bridge Applications”
  • Volume II – “Experimental Evaluation of Non-Composite Shallow Press-Brake-Formed Steel Tub Girders”
  • Volume III – “Evaluation of Modular Press-Brake-Formed Tub Girders With UHPC Joints”
  • Volume IV – “Field Performance Assessment of Press-Brake-Formed Steel Tub Girder Superstructures”
  • Volume V – “Fatigue Performance of Uncoated and Galvanized Composite Press-Brake-Formed Tub Girders”

The alliance says it provides essential information to bridge owners and designers on the unique benefits, innovative designs, cost competitiveness, and performance related to using steel in short span installations up to 140 feet in length.

SSSBA partners comprise bridge and buried soil steel structure industry leaders, including manufacturers, fabricators and representatives of related associations and government organizations.

For more news or information, visit shortspansteelbridges.org.