Integrating near‐surface mounted SMA and externally bonded CFRP for concrete beams strengthened in flexure

Abstract

This study aims to develop a new hybrid strengthening approach for reinforced concrete beams by integrating near‐surface mounted shape memory alloys (SMAs) and externally bonded carbon fiber reinforced polymers (CFRPs). Due to the superelasticity and shape memory effect of SMAs, the proposed strengthening can enhance the flexural strength of concrete beams without compromising ductility. The recovery behavior of deformed SMA wires was studied to determine the optimal prestrain level that can achieve the highest recovery stress. Afterward, the flexural performance of concrete beams strengthened with SMA, CFRP and both was investigated by performing three‐point tests. The results show that integrating SMA and CFRP has more influence on increasing the ultimate moment than the cracking moment and leads to a more significant improvement in the ultimate moment than individually utilizing SMA and CFRP. Besides, the effect of the integrated approach on enhancing the ductility is more notable than increasing the ultimate moment. The ultimate moment was analytically calculated, and the calculations show reasonable agreement with experimental results. The effects of the SMA and CFRP amount on the ultimate moment were also clarified through a parametric study.

Numerical evaluation of axial compressive behavior of hollow concrete columns reinforced with GFRP bars and spirals

“…In the last two decades, valuable research work has been carried out on applications of FRPs as retrofitting and strengthening material for structures [13][14][15][16][17] as well as on the use of FRP bars as flexural and shear reinforcement for concrete structures, 14,[18][19][20][21][22][23][24][25][26] therefore, different design codes have been developed for the design of FRP reinforced structures. [27][28][29] Later, several researchers focused on the application of FRP bars and ties in compression members.…”