Composite open web beam-joist and method of manufacture

A method of manufacturing a composite open web beam-joist from a beam having a closed uniform web layout, comprising:

• cutting the beam longitudinally along the closed uniform web layout to form a beam-joist portion including a first end, a second end opposite the first end, a top end, a bottom end opposite the top end, a first side, a second side opposite the first side, and an open web layout in the form of a sheet extending between the first end and the second end, the sheet defining a plurality of triangular web sections extending between the top end and the bottom end and having triangular openings between the triangular web sections, each of the triangular web sections including a base disposed at the top end and a peak disposed at the bottom end;
• cambering the beam-joist portion to bend the beam-joist portion along a horizontal plane thereof to form a cambered beam-joist portion;
• attaching a first chord angle beam to the first side of the cambered beam-joist portion at the peaks of the triangular web sections;
• attaching a second chord angle beam to the second side of the cambered beam-joist portion at the peaks of the triangular web sections;
• and
• attaching a plate vertically to the top end of the cambered beam-joist portion such that the plate extends longitudinally along the top end of the cambered beam-joist portion between the first end and the second end of the cambered beam-joist portion, the plate including a first side, a second side opposite the first side, a distal end, and a proximal end opposite the distal end, the first side including a flange at the distal end, the second side including a recess at the distal end;
• wherein the first chord angle beam is attached to the first side of the cambered beam-joist portion at the peaks of the triangular web sections via welding;
• wherein the second chord angle beam is attached to the second side of the cambered beam-joist portion at the peaks of the triangular web sections via welding.