Numerical analysis on the seismic performance of retangular concrete filled steel tube columns with strengthened bottoms

In order to optimize the influencial parameters of seismic performance of rectangular concrete filled steel tube (CFST) columns, a bottom strengthened rectangular CFST column whose bottom zone was welded with enhancing steel plates, was proposed. Based on the experimental results, the factors affecting the load-bearing capacity were analyzed. By means of the finite element analysis software ABAQUS, the specimens with different compression ratio, different strength grade of concrete, different height and thickness of the bottom strengthened steel plate were numerically analysed. The analytical results were compared with the experimental results. The study shows: as the axial compression ratio increases, the load-bearing capacity and the ductility decrease; as the strength grade of concrete increases, the bearing capacity also increases, but the decline of the performance curve steepens and the ductility decreases; when the height of the strengthened plate increases, the load-bearing capacity of specimens increases steadily, the energy dissipation capacity increases, and yet the ductility approximately holds without change; as the thickness of the strengthened plate increases, the load-bearing capacity improves only a little. The rectangular CFST column with bottom enhancing plates shows better seismic behavior and higher energy dissipation capacity if suitable constructional requirements are satisfied. Such structural configuration can be adopted in design of high-rise buildings. © 2016, Chinese Vibration Engineering Society. All right reserved.