SABRE2 represents a fundamental advancement in the design of steel I-section column, beam and beam-column members. With SABRE2, the consideration of attributes such as general member geometry, moment gradient, load height, end restraint, member continuity effects and beam-column strength interactions is handled via a rigorous computational framework, removing the need for tedious and relatively inaccurate Cb, K and beam-column strength interaction calculations.
SABRE2 achieves its solution efficiency by calculating the member inelastic stiffnesses using Stiffness Reduction Factors (SRFs) obtained from the Specification resistance equations, as well as by modeling the member behavior using a Thin-Walled Open-Section (TWOS) frame element. This frame element uses seven (7) degrees of freedom at each joint or nodal location – three translations, three rotations, and one warping degree of freedom.
SABRE2 is focused on the analysis of members and frames subjected to loading within the plane of a planar structure, but in which the strength limit states can involve in-plane or out-of-plane stability, including lateral-torsional buckling under combined axial loading and flexure. SABRE2’s current strengths are in the design assessment of individual members, either as isolated unbraced lengths with idealized end conditions or considering multiple unbraced lengths and the influence of continuity across braced locations. The modeling of the three-dimensional interaction between members at structural joints is still an area were further advances are needed.
The SABRE2 system is not aimed at “production design.” Only one load case or load combination is accommodated at any one time. SABRE2 is focused on teaching, demonstration, and fundamental validation of structural analysis and design concepts.
