Precast concrete column (1) for the support of structural modular floor, preferably dry assembled, comprising in its upper part a capital for the support (2) of beams (3), having the support capital (2) a square or quadrangular plan in such a way that four sides (21, 22, 23, 24) are defined for the support of the beams (3), in which each of the sides (21, 22, 23, 24) comprises concave recesses (4) of sides parallel to the axis of the beams (3) that define convex protrusions (5) which sides comprise bearing surfaces (6) such that when laying a beam (3), which ends are complementary to said recesses (4), the bearing forces have directions contained in a plane (41, 42, 43, 44) perpendicular to the axis of the beam (3), having said directions a horizontal component. The invention also refers to a beam complementary to this column and to slab segments, as well as to a structure provided with said columns, said beams and optionally also said slab segments.