Optimization of HPS 70W Applications

In February 1996, the Tennessee Department of Transportation, in cooperation with the Federal Highway Administration, the American Iron and Steel Institute, the U.S. Navy, and various steel plate manufacturers, agreed to design the first bridge in the United States to use HPS 485W (70W) steel. Since that time, the department has constructed a second bridge using HPS 485W (70W) and has let to contract a third bridge that uses HPS 485W (70W) in both quenched and tempered and thermomechanical controlled processing HPS 485W (70W) steel. These three projects were intended to help develop design and fabrication experience with the new HPS 70W steel. This paper will discuss lessons learned in the process and present optimization techniques employed. Some of the optimizations are directly associated with HPS 485W (70W) steel while others deal with economics brought about by employing money-saving details and properly interpreting the intent of the design specifications.