A modular space frame support system comprises an upper frame comprising a plurality of joists interconnected with a plurality of interconnection structures; a lower frame comprising a plurality of joists or chords interconnected with a plurality of interconnection structures; at least two interconnection structure brackets, wherein a first of the at least two interconnection structure brackets is connected to one of the plurality of interconnection structures of the upper frame and a second of the at least two interconnection structure brackets is connected to one of the plurality of interconnection structures of the lower frame, each interconnection structure bracket comprising a hollow tubular section, and at least one chord-engaging structure; and at least one chord secured at a first end to the first of the at least two interconnection structure brackets and at a second end to the second of the at least two interconnection structure brackets.