Steel girder slab details including A girder (/????rd?r/) is a support beam used in construction. It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing flanges separated by a stabilizing web, but may also have a box shape, Z shape, or other forms. For more details of Steel girder download this AutoCAD file or dwg format.