Strength of Composite Sections with Foamed and Lightweight Aggregate Concrete

Tests on steel hollow tubes of square and circular sections filled with foamed and lightweight aggregate concrete were conducted to investigate the contribution of these concretes to the strength of cross sections of composite members. Eight short column specimens filled with foamed and lightweight aggregate concrete, four specimens each, were tested under axial compression to calculate the squash load. Furthermore, eight simply supported short beams of similar sections, also four specimens for each concrete, were tested in bending to calculate the ultimate moment capacity. Unfilled steel sections of similar specimens were also tested and results were compared to those of filled sections. Theoretical values of squash loads and ultimate moment capacities for the test specimens are also included in this paper. The results of this investigation showed that the foamed concrete contribution to the squash load of composite sections is negligible while its contribution to the bending strength is quite significant. On the other hand, the contribution of lightweight aggregate concrete to the squash load and bending capacity is shown to be considerable.