This document discusses specifications for structural steel design published by organizations like AISC and AASHTO. It covers the two main design methodologies: Allowable Strength Design (ASD) and Load and Resistance Factor Design (LRFD). ASD divides the nominal strength by a safety factor while LRFD uses load and resistance factors. The document also classifies steel sections as compact, non-compact, or slender based on width-to-thickness ratios. It describes hot rolled, cold rolled, and built-up steel sections as well as their uses and properties. Built-up members are constructed by connecting plates or shapes and may be needed for large areas, rigidity, or connection requirements.