Cyclic behavior of mono and hybrid fibre reinforced high performance concrete exterior beam-column joints

Abstract

Beam-column joints have been recognized as critical elements in the seismic design of reinforced concrete moment resisting frames. When the frame is subjected to seismic forces, it should be designed and detailed properly in order to resist the effect of earthquake. The beam-column joints are failed due to bond and shear failure mechanism. Therefore adequate anchorage to longitudinal bars and confinement of core concrete in resisting shear should be provided. With the variation of hybrid composition, different seismic performance of the composite could be adjusted. The experimental study was carried out to investigate the effect of mono and hybrid fibres on the strength performance and structural behavior of high performance concrete beam-column joints subjected to cyclic loading. High performance concrete of M30 grade was designed using IS 10262-2009. Two types of steel fibres with aspect ratio of 33 and 60 were used in mono and hybrid form with a total volume fraction of 1.5%. Four sets of beam-column joints are cast and tested under cyclic loading to predict the load-deflection response, ductility characteristics, stiffness degradation, energy absorption capacity and deformation characteristics. The combination of 0.8% volume fraction of long hooked end steel fibre and 0.2% volume fraction of short crimped steel fibre specimen exhibits more ductility and energy absorption capacity when compared with that of the conventional concrete specimen and single fibrous concrete specimen.