Experimental Study on Axially Loaded Circle-Section Concrete Columns Confined by CFRP under Long-Term Load

In order to analyze the effect of creep in concrete and CFRP(Carbon Fiber Reinforced Plastic)on the axial compressive behavior of CFPP confined concrete column under the sustained load, a total of twelve circular columns specimens were tested under three types of the long-term axial load modes. The failure characteristics of specimens were observed and the influence of sustained load on the deformation, the peaks of the strain and the stress of CFPP confined concrete columns were studied under different load modes and ratio of sustained load. The experimental results show that all of the CFRP confined columns lose carrying capacity due to the rupture of CFRP in loop direction, and the position of rupture generally locates at the mid-height of concrete column. The axial strain of CFRP confined concrete is smaller than that of unconfined specimens, and the deformation increases with the load magnitude. Under different sustained load types, the long-term axial preload have different effects on peak stress and peak strain of CFRP confined concrete. In general, the peaks of the stress and strain of concrete decrease along with the increment of the ratio of sustained load. When the ratio of sustained load is relatively high, peak stress and strain will decrease about 13% and 6% , respectively.