Seismic performance of reinforced concrete columns after freeze-thaw cycles

The purpose of this study is to investigate the seismic performance of reinforced concrete columns after freeze-thaw cycles. Based on low cyclic loading tests of eight column specimens, the failure patterns, hysteresis loops, load carrying capacity, displacement and ductility factor, skeleton curves, stiffness degradation and energy dissipation capacity of frost-damaged concrete columns were analyzed. The effect of freeze-thaw cycles and axial compression ratios were investigated in detail. Test results show that for the column specimens under the same level of axial compression, with the number of freeze-thaw cycles increasing from 0 to 300, the plastic deformation capacity decreased whereas the rate of stiffness degeneration and strength decay increased continuously. The coupling effect of the deterioration of material and loosening of bond induced the value of equivalent viscous damping coefficients to decrease at first then increase, however, the cumulative energy dissipation decreased continuously. Test results also indicate that for the column specimens with the same level of frost damage, with the increase of axial compression ratio, the load carrying capacity and initial stiffness increased, whereas the deformability capacity, the equivalent viscous damping coefficients and the cumulative energy dissipation decreased obviously, respectively. (C) 2015 Elsevier Ltd. All rights reserved.