A prefabricated column assembly includes a hollow tubular column having a longitudinal axis. A gusset plate assembly includes a plurality of gusset plates connected to the column and extending laterally outward from the column in planes generally parallel to the longitudinal axis of the column. A first pair of the gusset plates extends laterally outward from the column along a first axis and defines a space for receiving an end portion of a first beam for mounting the first beam on the first pair of gusset plates. A second pair of the gusset plates extends laterally outward from the column along a second axis that is nonparallel and non-coincident with the first axis. The second pair of gusset plates defines a space for receiving an end portion of a second beam for mounting the second beam on the second pair of gusset plates to provide a bi-axial joint connection.