Fracture Toughness Characterization of High-Performance Steel for Bridge Girder Applications

The use of high-performance steel (HPS) in new bridge construction continues to increase as engineers and owners recognize the potential for cost savings and performance benefits. One intended advantage of HPS is the increase in fracture toughness when compared with conventional bridge steel. However, limited research has characterized HPS fracture toughness, and current material specifications provide no opportunity for owners to benefit from the improved performance resulting from increased fracture toughness. This paper presents the fracture toughness testing and analysis of eight A709 HPS 485W (70W) and 690W (100W) steel plates. The resulting fracture toughness values are used to determine tolerable flaw sizes for a representative girder flange. A comparison is made with tolerable flaw sizes based on toughness estimations from the current fracture critical material toughness specification. The results indicate that HPS is exhibiting toughness far in excess of current specification requirements. (c) 2019 American Society of Civil Engineers.