In a simplified workflow, the designer first selects a section based on the maximum bending moment. They then check the "Lateral-Torsional Buckling" (LTB) resistance. LTB occurs when the top flange of a beam tries to move sideways under a load. If the beam is braced frequently enough, this can often be ignored, greatly simplifying the math. Finally, the beam is checked for deflection to ensure it doesn't sag so much that it cracks the ceiling or alarms the occupants. Connections: The Critical Links
A traditional method where the calculated stress on a member must be less than a pre-defined "allowable" stress. Load and Resistance Factor Design (LRFD): simplified design of steel structures pdf