Experimental and numerical studies on seismic performance of rectangular concrete columns reinforced by CFRP bars with different ratios and positions

Abstract

In order to investigate the impact of Carbon Fibre-reinforced Polymer (CFRP) bar replacement ratio, CFRP bar position, and axial compression ratio on the seismic performance of concrete column, 8 specimens with the same geometry and reinforcement ratio but different CFRP bar replacement ratios and positions were constructed, and then tested under combined lateral low cyclic reversed load and different axial compression ratios. The seismic performances, such as failure mode, hysteretic behavior, and self-centering capacity were researched based on the test results. Furthermore, a numerical analysis model was built by OpenSees program to predict the seismic performance of the specimens, and then verified by comparing with experimental results. The results show that: (1) The peak lateral load of the columns increased with the increase of CFRP bar replacement ratio, and residual drift ratio decreased with the increase of CFRP bar replacement ratio. (2) The energy dissipation coefficients of all columns were inversely proportional to CFRP bar replacement ratio under the same axial compression ratio. (3) The peak lateral load and energy dissipation capacity of the specimen under the compression ratio of 0.3 were greater than that under the compression ratio of 0.15. (4) The failure modes of specimens reinforced with CFRP bars were characterized by compressive rupture of CFRP bars at drift ratio larger than 4%. (5) The numerical analysis results were in good agreement with the experimental results, and the numerical analysis model is able to take into account the effect of CFRP bar replacement ratios, CFRP bar positions, and axial compression ratio on the seismic performance of the specimens.