i am working on a cost effective ramp to carry a load of 100kgs on very light weighted structure. I hit a road block now, on a frame horisontal and 415mm wide X 650mmm long. with a thickness of 20mm. This frame should be below a kg weight but carry a static load capacity of 80 to 100kgs. With an aluminium structure, tack welded with cross sections of 1.5mm thick channels ( iteration 1), Langles with 1.2mm thk, cross sections, i am buidling it. Pl. heelp me know how to arrive at the moment of inertia for this bbeam structure. Thanks