In a plural grid modular space frame system of the type including at least two uniform dimensioned substantially rectangular grid planar chord frames held apart and substantially parallel by diagonal struts, one frame being out of registration with the other frame by one-half grid dimension in each substantially rectangular direction so that each chord intersection point on one frame is substantially apart from and opposite an open center of a grid rectangle of the other frame, each of said diagonal struts being one of a group of four struts extending from each said chord intersection point on one frame to each of the four nearest chord intersection points bounding said grid rectangular of the other frame to form a grid module, the improvement comprising:
- a plurality of continuous chords;
- a plurality of tie chords, said tie chords and said continuous chords being disposed in two substantially uniform dimensioned substantially rectangular grid planar chord frames, in each one of which all of said chords lie in a single plane for disposing any associated chord forces in said single plane, said continuous chords extending in one direction of said substantially rectangular grid with said tie chords extending in the other substantially rectangular direction at an angle to said one direction, each of said tie chords being a substantially discontinuous chord and extending one grid dimension from the intersection point with one of said continuous chords to the intersection point with the next continuous chord, said tie chords and said continuous chords being comprised of elongated hollow substantially rectangular tubes having four substantially flat side walls;
- a plurality of diagonal struts, each extending from one of said chord intersection points on one of said chord frames to one of the four nearest chord intersection points on the other of said frames, said diagonal struts being elongated hollow tubes having side walls;
- and
- interconnection means for joining said continuous chords, said tie chords and said diagonal struts together at each of said intersection points, said interconnection means comprising threaded bolt means, threaded nut means threadably engageable with said threaded bolt means, and a plurality of bent plate connectors substantially uniformly modularly spaced apart along the longitudinal axis of each of said continuous chords throughout the length thereof and secured thereto at each of said interconnection points, each of said bent plate connectors being a substantially continuous member having a substantially straight portion secured to said continuous chord and a plurality of angulated portions extending therefrom to substantially define the planes of said diagonal struts in said space frame, said straight portion bearing against an external area of one of said flat side walls of each of said chords with said angulated portions being in load bearing relation with said struts, said bent plate connectors each having apertures through each of said portions within said load bearing area to receive said threaded bolt means, said continuous chords, said tie chords and said diagonal struts each having tube wall apertures, within said load bearing area alignable with said bent plate connector apertures for receiving said threaded bolt means disposed through said bent plate connector apertures, each of said threaded bolt means being disposed through said aligned bent plate connector and tube wall apertures and engaged with said threaded nut means so that each of said tie chords and diagonal struts is secured to said respective bent plate connector at each of said intersection points, said interconnection means further comprising means for fixedly securing each of said respective bent plate connector straight portions to said continuous chords at said intersection points, said continuous chords being concentrically loaded in said space frame and said substantially discontinuous tie chords being eccentrically loaded in said space frame, said continuous chords in said space frame having said bent plate connectors secured thereto being substantially stronger in compression and local bending than said substantially discontinuous tie chords in said space frame, said continuous chords being common for a plurality of said grid modules with said spaced apart bent plate connectors secured to each of said common continuous chords defining said intersection points for said plurality of grid modules, whereby enhanced strength in column activity and transverse bending for said modular space frame is provided.