ASEISMIC PERFORMANCE TEST AND FEM ANALYSIS OF UNIFORM SECTIONAL CFST LATTICE COLUMN WITH FLAT LACING TUBES

To study the aseismic performance of uniform sectional concrete-filled steel tubular (CFST) lattice columns with flat lacing tubes, the quasi-static tests are conducted for seven test specimens focused on the effects of different concrete strength, longitudinal spacing of CFST limbs, and vertical spacing of lacing tubes on stiffness, strength, and ductility. The hysteretic behaviors of specimens are also simulated with a fiber model using OpenSees platform, and the results obtained by fiber element model agree well with test results. By analyzing the damage modes, the load-displacement hysteretic loops, the skeleton curves, and the following conclusions can be derived. All the specimens have a good aseismic performance, characterized by the overall bending damage; and the horizontal load-displacement hysteresis curves are plump; with the increase of concrete strength from C40 to C60, the bearing capacity is improved by 5.7%; as the longitudinal spacing of CFST limbs increased from 250 mm to 650 mm, the bearing capacity and the ductility factor are significantly improved by 14.5% and 6.8%; as the vertical spacing of lacing tubes increased from 200 mm to 313 mm, the bearing capacity and the ductility factor are respectively reduced by 12.9% and 12.0%.