High Performance Steel Designers' Guide
8.0 Closing Remarks
The development of high performance steels is a very successful story of putting research into practice in a very short span of time. It exemplifies the vision and leadership of a strong and collaborative partnership between governmental agencies, industry and academia. In recognition of the accomplishments of the joint effort, the Civil Engineering Research Foundation (CERF) awarded the Charles Pankow Award to AISI, FHWA and the Navy.
The cost effective application of HPS in bridge design and construction has already been demonstrated by the performance experience of in-service HPS bridges in many states as shown in Appendix C HPS Scoreboard. The major benefits of HPS are noted below.
- The high strength of HPS allows the designers to use fewer lines of girders to reduce weight and cost, use shallower girders to solve vertical clearance problem, and increase span lengths to reduce the number of piers on land or obstructions in the streams.
- Improved weldability of HPS eliminates hydrogen induced cracking, reduces the cost of fabrication by lower preheat requirement, and improves the quality of weldment by using low hydrogen practices.
- Significantly higher fracture toughness of HPS minimizes brittle and sudden failures of steel bridges in extreme low service temperatures. Higher fracture toughness also means higher cracking tolerance, allowing more time for detecting and repairing cracks before the bridge becomes unsafe.
- Good 'weathering characteristics' of HPS assures long-term performance of unpainted bridges under atmospheric conditions.
- Optimized HPS girders can be attained by using a hybrid combination of HPS 70W in the negative moment top and bottom flanges, and Grade 50W or HPS 50W in other regions.
- Optimized HPS girders have shown to result in lower first cost and are expected to have lower life-cycle cost.
High performance steels are justifiably claimed to be 'The Bridge Construction Material for the New Century.'