Inelastic failure of high strength steel wide flange beams under moment gradient and constant moment loading

摘要

Compactness and bracing provisions for the design of steel beams are formulated so as to ensure that the resulting beam exhibits adequate structural ductility. The specification of such compactness and bracing requirements involves several assumptions. One such assumption centers on the constitutive nature of the structural steel being used. Such material response assumptions, which are inherent in existing codes, are valid for designs incorporating most grades of mild carbon steels and many HSLA grades. However, it appears from the current research that these material response assumptios may produce invalid compactness and bracing criteria when applied to the design of I-shaped beams made from the high performance steel grade HSLA80. The mechanical propertis of HSLA80 steel deviate from the properties of more conventional structural steels in several key areas of its response. One such area is the relative closeness of they yield strength and ultimate strength of HSLA80 which is not observed in mild carbon steels.