Experimental investigation on the flexural behavior of steel cold-formed I-beam with strengthened hollow tubular flanges

摘要

This research presents an experimental study to examine the flexural behavior of steel cold-formed I-beam with strengthened hollow tubular flanges. Nineteen of cold-formed steel I-beam with hollow tubular flanges were prepared and experimentally tested on four-point bending tests. One of these specimens was not strengthened, which used as a control specimen, and eighteen specimens were strengthened with filling the tubular flanges by different materials. Twelve specimens were strengthened at the compression hollow tubular flanges only, with and without shear connectors. Finally, six specimens were strengthened at the compression and tension hollow tubular flanges. The strengthened materials used are different types of wood wastes (Particleboard Wood-Sawdust with cement mortar- Sawdust with epoxy- Sawdust with polyester), light weight concrete, and polymer-mortar. All specimens were loaded by two vertical loads to failure. Specimens' mode of failure and vertical displacements were recorded. Vertical load-deflection at mid-span relationships have been analyzed to study the effect of strengthened materials. It was observed that maximum capacity was achieved by using polymer-mortar rather than the other materials. Using shear studs and strengthened compression and tension flanges did not show an obvious effect on the ultimate load of the tested specimens compared to those that were strengthened the compression flanges only. For all the strengthened specimens, improving in the load-mid span deflection relationships were achieved compared with the control specimen. The bending moment capacities were compared with the expected values using the Egyptian Code of Practice for Steel Construction (LRFD), which indicates that the design method of this code is conservative in comparison to the experimental test results, but it is not conservative in expected the moment capacities of strengthened specimens that used the Sawdust with cement mortar and light weight concrete materials.