Shallow single plate steel tub girder

A method of manufacturing a steel tub girder member comprising:

• configuring a roll-forming machine (80) having a plurality of roll-forming stations (82A-82R) to form a pair of external upper longitudinal bends (18) and a pair of internal lower longitudinal bends (20);
• passing unheated steel plate material through the roll-forming machine, wherein at least some of the plurality of roll-forming stations progressively cold form the upper longitudinal bends and the lower longitudinal bends to produce the steel tub girder member;
• and
• configuring a subset of the plurality of roll-forming stations to induce a positive camber in the unheated steel plate material as the unheated steel plate material is passing through the roll-forming machine;
• wherein the subset of the plurality of roll-forming stations includes a first station (82P) configured to provide a fixed-roller anchor point, a second station (82Q) including at least one vertically-actuated roller configured to automatically move up and down to engage the unheated steel plate material, and a third station (82R) configured to provide another fixed-roller anchor point.