Load supporting frame assembly

A load supporting frame assembly comprising, in combination, a pair of longitudinally extending transversely spaced main beams, a plurality of central transverse members extending between said main beams in longitudinally spaced relationship along said main beams and a plurality of transverse outboard members outwardly extending from said main beams in longitudinally spaced relation along said main beams, a longitudinally extending side rail secured to the extending ends of said transverse outboard members, said main beams having a generally I-shaped configuration and comprising a vertically disposed web having an upper edge and a lower edge, an upper flange formed by a pair of angle members each having a pair of flanges perpendicular to each other and secured back-to-back to the web at the web upper edge by one flange each whereby the other flanges fall in a common plane, and a lower flange formed by at least one angle member having a pair of flanges perpendicular to each other secured to the web at the web lower edge by one flange whereby the other flange is in a plane in proximity to said lower edge, a connector for detachably securing said transverse central members and said transverse outboard members to said main beams comprising a planar base adapted to abut the beam web, and one of said angle member flanges or said connector planar bases having a key formed thereon and the other having a mating keyway formed therein whereby the angle members, connectors and transverse members are self-aligning with each other when assembled and secured together.