A bedplate assembly of a wind turbine is provided. The bedplate assembly includes a rotor shaft with a first end coupled to a rotatable hub of the wind turbine via a rotor flange and a second end coupled to a gearbox. The bedplate assembly also includes a bedplate support frame coupled to the gearbox and to the rotor shaft for supporting the gearbox. The bedplate support frame includes a torque arm support device for supporting torque arms of the gearbox. The bedplate support frame also includes a circular support for housing a shaft support bearing for supporting the rotor shaft at the first end. Further, the bedplate support frame includes a cross-structure located under the rotor shaft, wherein the cross-structure comprises one or more arms connected internally to a first side wall and a second side wall.