Beam assembly with multi-hollow formation

A beam assembly comprising:

• a first beam comprising a first tubular portion and a first projecting portion extending along the first tubular portion;
• a second beam comprising a second tubular portion and a second projecting portion extending along the second tubular portion;
• wherein the first and second beams are formed from a metal sheet, the first and second tubular portions each having a seam disposed along a length thereof that is defined by an edge section of the metal sheet attached along an intermediate section of the metal sheet, and the first and second projecting portions integrally protruding at the seam from the intermediate section of the metal sheet;
• and
• wherein the first beam is attached to the second beam with the first projecting portion attached to the second tubular portion and the second projecting portion attached to the first tubular portion to define a hollow area between the first and second projecting portions.