This lecture covers the pre-dimensioning of steel beams and the use of i-Cremona for steel beams, similar to reinforced concrete beams. It emphasizes the importance of using [N] and [mm] as units and discusses the dimensions of steel profiles. The lecture also includes information on steel beams with wide flanges, applets for metallic beams, and sections of double T beams with dimensions and weights. It concludes with an overview of an applet for designing composite steel-concrete beams.