A connector assembly, comprising an upper connector coupled to a lower connector and a gusset plate sandwiched between the upper and lower connectors, the lower connector comprising: a lower connector hollow body having lower connector first and second ends, the first end being adapted for receiving a first end of a first module frame and the second end being adapted for coupling to the gusset plate; at least a pair of lower connector bosses coupled to the lower connector hollow body; and at least a pair of lower connector arms, each lower connector arm being coupled to and extending from the lower connector boss and having an aperture, the aperture receiving a fastening means to couple the lower connector to the upper connector; the upper connector comprising: an upper connector hollow body having upper connector first and second ends, the first end being adapted for coupling to the gusset plate and the second end being adapted for receiving a first end of a second module frame; at least a pair of upper connector bosses coupled to the upper connector hollow body; and at least a pair of upper connector arms, each upper connector arm being coupled to and extending from the upper connector boss and having first and second apertures (13, 12), the first aperture receiving a coupling means to couple the upper connector to the gusset plate and the second aperture receiving the fastening means to couple the lower connector to the upper connector; and the gusset plate comprising: a first face, a second face and through holes (31, 32) for receiving the coupling and fastening means (25, 34) to couple the upper and lower connectors. the lower connector comprising: a lower connector hollow body having lower connector first and second ends, the first end being adapted for receiving a first end of a first module frame and the second end being adapted for coupling to the gusset plate; at least a pair of lower connector bosses coupled to the lower connector hollow body; and at least a pair of lower connector arms, each lower connector arm being coupled to and extending from the lower connector boss and having an aperture, the aperture receiving a fastening means to couple the lower connector to the upper connector; a lower connector hollow body having lower connector first and second ends, the first end being adapted for receiving a first end of a first module frame and the second end being adapted for coupling to the gusset plate; at least a pair of lower connector bosses coupled to the lower connector hollow body; and at least a pair of lower connector arms, each lower connector arm being coupled to and extending from the lower connector boss and having an aperture, the aperture receiving a fastening means to couple the lower connector to the upper connector; the upper connector comprising: an upper connector hollow body having upper connector first and second ends, the first end being adapted for coupling to the gusset plate and the second end being adapted for receiving a first end of a second module frame; at least a pair of upper connector bosses coupled to the upper connector hollow body; and at least a pair of upper connector arms, each upper connector arm being coupled to and extending from the upper connector boss and having first and second apertures (13, 12), the first aperture receiving a coupling means to couple the upper connector to the gusset plate and the second aperture receiving the fastening means to couple the lower connector to the upper connector; and an upper connector hollow body having upper connector first and second ends, the first end being adapted for coupling to the gusset plate and the second end being adapted for receiving a first end of a second module frame; at least a pair of upper connector bosses coupled to the upper connector hollow body; and at least a pair of upper connector arms, each upper connector arm being coupled to and extending from the upper connector boss and having first and second apertures (13, 12), the first aperture receiving a coupling means to couple the upper connector to the gusset plate and the second aperture receiving the fastening means to couple the lower connector to the upper connector; and the gusset plate comprising: a first face, a second face and through holes (31, 32) for receiving the coupling and fastening means (25, 34) to couple the upper and lower connectors.