Modular polymer matrix composite support structure and methods of constructing same

A high load bearing support structure comprising:

• at least one modular structural section;
• and
• a support system attached to said at least one modular structural section, wherein said at least one modular structural section comprises:
• at least one oblong beam comprising a pair of lateral flanges each having a terminal edge extending longitudinally along said at least one oblong beam, and a generally U-shaped medial web extending from one of said pair of lateral flanges to an opposing one of said pair of lateral flanges, said pair of lateral flanges being mounted to and supported by said support system, said at least one oblong beam being a unitary structure and formed of a polymer matrix composite material comprising reinforcing fibers and a polymer resin, wherein a first portion of said reinforcing fibers in a floor portion of said medial web of said at least one oblong beam are unidirectionally oriented and a second portion of said fibers in a vertical side wall portion are in a quasi-isotropic orientation, wherein said second portion of said fibers in said side wall portion of said medial web of said at least one oblong beam are in a quasi-istotropic orientation wherein said quasi-isotropic orientation comprises orientations of about 0.degree. about 90.degree., about +45.degree., and about -45.degree., wherein about 25% of said fibers have an orientation of about 0.degree., about 25% of said fibers have an orientation of about 90.degree., about 25% of said fibers have an orientation of about +45.degree., and about 25% of said fibers have an orientation of about -45.degree., and wherein said fibers are oriented to provide a nearly uniform stiffness in all directions of said support structure;
• and
• a load bearing deck mounted to said pair of lateral flanges,
• wherein said at least one oblong beam transfers load from said deck to said support system.