The following definitions apply for purposes of this section:
Slab. A flexural member of uniform depth supporting area loads over its surface.
A slab may be reinforced for flexure in one or two directions.
Joist-slab. A ribbed slab with ribs in one or two directions. Dimensions of such a slab must be within the ACI 318 Building Code limitations (see Art. 9.54).
Beam. A flexural member designed to carry uniform or concentrated line loads. A beam may act as a primary member in beam-column frames, or may be used to support slabs or joist-slabs.
Girder. A flexural member used to support beams and designed to span between columns, walls, or other girders. A girder is always a primary member.
