Effects of BFRP retrofitting and cyclic loading on the load-bearing capacity of reinforced concrete beam-column joints

Abstract

This paper investigates the effects of Basalt fiber reinforced polymer (BFRP) retrofitting and cyclic loading on bearing capacity of reinforced concrete beam-column joints with orthogonal beams. Experiments were conducted on eight beam-column joints. These joints were classified into four groups; each group had two joints. One group was not retrofitted (control group). Three remaining joints were retrofitted with various configurations. For each group, one joint was monotonically loaded and one joint was cyclically loaded. The results showed that damage mode was in the form of concrete crushing in the compression zone and concrete cracking in the tension zone. The damage was concentrated on the beams, while the damage did not appear on the columns. Under monotonic loading, BFRP retrofitting increased the ultimate load of the joints by about 8.5%. Under cyclic loading, BFRP retrofitting increased the ultimate load by 3.3–7.0% compared with that of the control joint. Cyclic loading had a great influence on the ultimate load capacity of the joints. Compared to the control joint subjected to monotonic load, cyclic loading reduced the ultimate load of the unretrofitted joint by 14.3% and the ultimate load capacity of BFRP retrofitted joints by 8.3–17.2%.