Zhong-qiu, Boi-Hai, Lei, Wen-Jie
6 short columns and 27 slender columns containing lightweight aggregate concrete were tested under axial compression to compare and study failure mode and failure mechanisms.
Experimental Study, Results, and Discussions
This research paper investigated and analyzed high-strength and lightweight concrete-filled steel tubes. Specifically, macroscopic deformation characters, axial force-longitudinal strain curves, failure modes, and failure mechanisms of lightweight CFTs were reviewed. For this research paper, a compressive axial test of 33 short and slender specimens is completed and the overall performance is discussed. The parameters for this test include the slenderness ratio, pipe size, and prism strength of concrete. Each axial compressive load was maintained for two to three minutes during the testing to allow for full deformation development. Failure modes occurred from excessive lateral deformation. As the load decreased, the lateral deflection increased at a greater rate. This research paper determined that a greater slenderness ratio will result in a lower bearing capacity and increasingly higher plastic deformation rate. Additionally, it was determined that the stability coefficient and the peak strain of concrete have a linear relationship.
Design Formulation
New equations are proposed to calculate lateral deformation, using the hoop strain and longitudinal strain of the steel column.
Reference
Zhong-qiu, Fu, et al. “BEHAVIOR OF LIGHTWEIGHT AGGREGATE CONCRETE FILLED STEEL TUBULAR SLENDER COLUMNS UNDER AXIAL COMPRESSION .” Advanced Steel Construction, vol. 7, no. 2, 23 Nov. 2010, pp. 144–156.