| Concrete-filled steel rectangular tubular (CFRT) columns are becoming more andmore widespread structural applications in seismic region,because they have theadvantages of better stability and carrying capacity, simple connections betweencolumns and beams, convenient construction, regular shape and excellent earthquakeresistant properties. Now many countries have carried a lot of research on seismicbehavior of CFRT, but the effect of seismic behavior is based on a single experimentalfactor, few report is about the experimental research by using orthogonal designmethod, so it is important in research of the performance of CFRT structure inearthquake conditions.In this paper, nine concrete-filled rectangular steel tubular columns are studiedunder cyclic horizontal loading. The charcteristics of its failure, capacity of loading,distortion, energy absorption and properties of rigidity degradation are studied. Usedanalysis of variance, the best combination among axial compression ratio, steel ratioand slenderness-ratio is found.The results of this experiment indicated: (1) the hysteretic curves of CFRTcolumns are plump in shapes, and have no significant pinch phenomenon. CFRTcolumns have more high horizontal capacity and better deformation under cyclicloading. (2) The intensity degradation of CFRT columns is smooth. (3) Analyzedductility coefficient, axial compression ratio, steel ratio and slenderness-ratio aresignificant factors on earthquake resistant properties. Steel ratio is the first influentialfactor,axial compression ratio is the second influential factor, slenderness-ratio is thethird influential factor. The best combination of earthquake resistant properties isA1 B2 C3 ,that is to say, axial compression ratio n equals one point two,slenderness-ratioλ equals seventeen point sixty, steel ratioα equals zero point onehundred eighty one.
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