Direct analysis for structures made of high strength steel

Buckling curves for high strength steel are not easily obtainable because of limited resources in testing the members under high loads, resulting in difficulty for engineers to design structures made of high strength steels. This paper proposes a method based on direct analysis (DA) method for design of high-strength steel members and frames allowing explicit modeling of residual stresses such that numerical simulation analysis and design can be conducted as substitutes of full-scale physical tests. A section analysis technique based on quasi-Newton iterative scheme is adopted to take into account the effects of residual stress with the geometrical imperfections measured. Residual stress for the welded box-sections and H-sections fabricated by high-strength steel are measured and adopted for illustration. To complete the consideration of buckling and second-order effects, the initially crooked with arbitrarily-located-hinge (ALH) element is introduced. A fiber hinge model using the sectional strength-iteration surfaces is used for modeling of material yields. Several examples are employed to verify the accuracy and validity of the proposed approach. This paper is to contribute to the formulation of a versatile numerical procedure to account for residual stresses and geometric imperfections separately for design of high-strength steel members and frames where physical tests are expensive.