The five volumes of the work into ‘Development and experimental testing of press-brake-formed steel tub girders (PBTG) for short span bridge applications’ are now available for free download from the SSSBA’s website (link opens in new tab). The work was compiled by Professor Karl Barth of West Virginia University and former research assistant Dr Greg Michaelson, who is now at Marshall University.

The new technology involves cold-bending standard mill plate to form a trapezoidal box girder. The steel plate can either be weathering steel or galvanised steel. Once the plate has been press-brake-formed, shear studs are then welded to the top flanges. A reinforced concrete deck is 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; the team says that the technique allows for accelerated construction and reduces traffic interruptions.

Press-brake-formed steel tub girder bridge

"Press-brake-formed steel 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, minimising traffic delays,” said SSSBA director Rich Tavoletti. “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. 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.”