Studies on hybrid fibre reinforced beam-column joints under reverse cyclic loading

Abstract

Under seismic excitation, the beam column joint region in a framed structure is subjected to horizontal and vertical shear forces, whose magnitudes are typically many times higher than those with the adjacent portions of beams and columns. If the joint is not carefully detailed, the beam column joint may become the weak link. To prevent this weak link, superior detailing technique should be given in the joint region. The primary objective of this study is to devise innovative joint formed by using hybrid fibre (combination of steel and synthetic fibre) reinforced joint. The entire study was carried out in four phases. In the first and second phases there were twenty eight numbers of exterior beam-column joints (seven types) using M20 and M25 concrete, were cast and tested under cyclic and reverse cyclic loading. In the third phase, ten numbers of exterior beam-column joint were cast in the similar manner but with M60 concrete. The results of reverse cyclic loading tests performed on the exterior beam column joint models indicate that the fibre reinforced concrete is a partial replacement of confining reinforcement to provide adequate ductility. An analytical investigation of experimentally tested exterior beam column joint specimens were carried out in the fourth phase of this study using Finite Element Software ABAQUS and the results were discussed and compared with the experimental results. The analytical and experimental results are correlating well. The hybrid fibre combination in the beam column joint region reduces the damages caused by the earthquakes. This is a positive step to save humanity.