Three-Dimensional Benchmark Problems for Design by Advanced Analysis: Impact of Twist

Design codes for steel structures continue to provide additional opportunities for the use of more advanced methods of nonlinear analysis. As the complexity of the analysis increases, it becomes more important for the designer to validate the capabilities of their analysis software and, just as importantly, their ability to properly utilize it. Many benchmark problems can be found in the literature; however, few include three-dimensional behavior and fewer include I-shaped sections, which are torsionally flexible and where warping restraint can be significant. This paper introduces a new set of benchmark problems that contribute to a much needed database of examples in which the accurate modeling of three-dimensional or spatial behavior is essential. A secondary goal of the paper is to illustrate new steel design provisions and the type of comparisons that were part of their development.