Press-Brake Tub Girder System Introduced for Short-Span Bridges

See the Amish Sawmill Bridge case study. (Photo courtesy of SSSBA) 

The press-brake tub girder system (PBTG) — a new technology for short-span steel bridge applications — developed by the Short Span Steel Bridge Alliance (SSSBA) in conjunction with West Virginia University and Marshall University, has evolved from a research project to a viable solution for short-span bridges. Last year it was introduced in the construction of the Amish Sawmill Bridge in Buchanan County, Iowa. In collaboration with members of SSSBA, the Iowa Department of Transportation and the Buchanan County Engineer worked to construct the bridge with funding through the Innovative Bridge Research and Deployment Program (IBRD).

According to SSSBA, the PBTG system was designed specifically for the short-span bridge market and offers a number of advantages over traditional systems used in short-span bridge construction. A standard plate size is folded into a trapezoidal shape using a press brake, similar to a larger steel tub girder. Using standard plate sizes ensures material is readily available and pricing is economical. Unlike the larger steel tub girder, the press-brake tub girder does not require welding and therefore fabrication time is significantly reduced. One girder can be produced in as little as 45 minutes, says SSSBA. And because of the girder’s lighter weight, a precast deck can be placed on the girder and shipped to the jobsite, a significant advantage in accelerated bridge construction (ABC). The weight savings also allows for installation with smaller cranes or by county engineering crews. Through conversations with county engineers, the steel industry has determined that county engineers can better control costs and find savings by using their own crews for construction.

The Federal Highway Administration recently awarded the Ohio Department of Transportation and Muskingum County, Ohio, an Accelerated Innovation Deployment (AID) grant for the installation of a PBTG system with a sandwich plate deck system. West Virginia is also evaluating two locations for the system.

More information on the PBTG system can be found on the SSSBA website, here.