R/C Space Frames with Column Axial Force and Biaxial Bending Moment Interactions

Hysteretic responses of single mass reinforced concrete columns subjected to seismic biaxial base motions with constant and varying axial load are studied using the triaxial spring model. Comparisons are made with the trilinear degrading and the biaxial bilinear models based on plasticity theory. Varying axial load on columns due to overturning effects of 10‐story space frames subjected to biaxial base motions are investigated. The results indicate the axial force and biaxial bending moment interaction on R/C column is important.