Experimental and Analytical Examination of Various CFRC-Strengthening Combinations for Buildings with Poor Concrete Quality

This study presents a rapid and economic strengthening method for existing RC framed and infill walled buildings with poor concrete quality especially those located in seismic regions and such as Turkiye. An important difference of this paper from similar studies is the preparation of frame specimens using low-quality concrete, aiming for a more accurate simulation of the existing building stock in Turkiye. To achieve this goal, six reinforced concrete (RC) specimens with different combinations of carbon fiber-reinforced cement-based composites (CFRC) were fabricated. These specimens were both experimentally and analytically tested under reversed repeated axial loading and compared with un-strengthened bare and infilled specimens. Accordingly, certain parameters such as maximum lateral load capacity, stiffness, damage-crack formations, ductility, and energy dissipation capacities were examined. The application of CFRC-strengthening prevented the dispersion and out-of-plane collapse of the infill walls. The strengthened specimens exhibited fewer cracks in comparison to the un-strengthened bare and infilled specimens. In addition to presenting the CFRC strengthening combination with the highest overall performance, this study also introduced cost-effective alternatives with acceptable performance and ineffective application combinations with inadequate strength. In conclusion, this study is believed to make a valuable contribution to the field and serves as a useful guide for retrofitting structures constructed in seismic regions with poor concrete quality.