Study On Hysteretic Behavior Of Three-Legged Concrete-Filled Steel Tubular Latticed Columns

Concrete-filled steel tubular (CFST) latticed members have a large cross-sectional moment of inertia due to the main load-bearing limbs being away from the centroidal axis. Compared with single CFST members under the same conditions, CFST latticed members have a lighter weight, a better axial stability and a larger flexural stiffness. In practical engineering, CFST latticed members are adopted when the member has the large load eccentricity ratio and/or slenderness ratio, such as column of industrial plants, trestle column, arch rib of arch bridge, etc. Currently, the static performance of CFST latticed columns and hysteretic behavior of two-legged and four-legged CFST latticed columns has been studied by the researchers; however, there is no literature about the seismic performance of three-legged CFST latticed columns. To promote the application of three-legged CFST latticed columns in the earthquake area, it is necessary to comprehensively investigate the hysteretic behavior of three-legged CFST columns.The hysteretic performance of three-legged CFST latticed columns were experimentally studied in this paper and the calculating method for horizontal bearing capacity of the tested specimens was also discussed. The main contents are as following:(1) The related studies available in the literature, including seismic performance of single CFST columns, static behavior of CFST latticed columns and seismic performance of CFST latticed columns, were reviewed.(2) Tests on six three-legged CFST latticed columns and two corresponding three-legged steel latticed columns under cyclic loading were carried out to investigate the effect of diameter-to-thickness ratio of column limbs and axial compressive load ratio of the latticed column on the load versus displacement hysteretic and skeleton curves, initial stiffness, energy dissipation and displacement ductility of the specimens.(3) The method for bearing capacity prediction of three-legged CFST and steel latticed columns was investigated by comparison between the calculated horizontal bearing capacities using the design codes and the experimental results.