Mehrab Ekraghanbari - M.Sc, Department of Civil Engineering, University of Mazandaran, Babolsar, Iran.

In this research, effectiveness of Carbon Fiber Reinforced Polymer (CFRP) has been investigated for improving seismic performance of concrete frames. For this purpose, one reinforced concrete frames with ۸ story is designed in accordance with moderate ductility regulation of ACI ۳۱۸-۱۴. In order to improve the seismic performance of structures, CFRP reinforcement in the areas susceptible to inelastic behavior has been used as the main retrofit technique in this paper. Achieving the code-based acceptable level of regulation has been considered as the main objective in retrofitting the above-mentioned buildings. In the second step, satisfying the weak beam- strong column criterion even after the application of CFRP retrofits is considered. Standard No. ۳۶۰ (according to ASCE ۴۱-۱۳) is utilized for the evaluation of seismic performance of the selected structure. Then Seismic responses of the original and retrofitted structures were evaluated using nonlinear time-history analysis performed under a set of long duration ground motions. The results were compared in terms of distribution of maximum inter story-drifts, residual displacement, hysteresis energy and plastic rotations at beams and columns. The results indicate that the plastic hinge relocation technique for beams, using the suggested flange-bonded technique, can effectively improve the seismic performance of existing code-compliant RC structures.In this research, effectiveness of Carbon Fiber Reinforced Polymer (CFRP) has been investigated for improving seismic performance of concrete frames. For this purpose, one reinforced concrete frames with ۸ story is designed in accordance with moderate ductility regulation of ACI ۳۱۸-۱۴. In order to improve the seismic performance of structures, CFRP reinforcement in the areas susceptible to inelastic behavior has been used as the main retrofit technique in this paper. Achieving the code-based acceptable level of regulation has been considered as the main objective in retrofitting the above-mentioned buildings. In the second step, satisfying the weak beam- strong column criterion even after the application of CFRP retrofits is considered. Standard No. ۳۶۰ (according to ASCE ۴۱-۱۳) is utilized for the evaluation of seismic performance of the selected structure. Then Seismic responses of the original and retrofitted structures were evaluated using nonlinear time-history analysis performed under a set of long duration ground motions. The results were compared in terms of distribution of maximum inter story-drifts, residual displacement, hysteresis energy and plastic rotations at beams and columns. The results indicate that the plastic hinge relocation technique for beams, using the suggested flange-bonded technique, can effectively improve the seismic performance of existing code-compliant RC structures.

CFRP, Long duration ground motion, Nonlinear time-history analysis, Seismic retrofit, Hinge plastic