Built-up 3D Trusses from Scrap Bars Used as Transfer Beams

Abstract

The transfer beam used in structural testing such as ASTM method of testing for flexural strength of concrete using simple beam with third-point loading are generally built-up from structural steel using wide flange shapes which are generally expensive and heavy. There are a lot of scrap bars left over from the tensile test and these bars virtually can be used to resist load even through they are tested until yielding occurs. Alternative transfer beams built-up from scrap deformed bars of diameter 25 millimeters were made in the form of 3D trusses with sizes of 0.2x0.3x1.0 meters and 0.2x0.3x1.5 meters. Each truss was analyzed and tested under a single point load of 10 tons and 15 tons with the corresponding deflections at mid-span of 0.53 millimeters and 0.97 millimeters respectively. The testing results showed that both trusses performed elastically. The maximum deflections were within the required limit of 1.7-2.5 millimeters (L/600) . Cracking or failure of welds and buckling of truss members did not occur. Both trusses can be used as transfer beams.