Evaluation of RC and SFRC exterior beam–column joint under cyclic loading for reduction in lateral reinforcement of the joint region

Abstract

The integrity of a reinforced concrete structure should be safe and stable under lateral loads, especially those structures that depend on the behaviour of the beam–column joint. The ductility capacity of structural elements has a key role to play in seismic design. The ability of the structure to sustain levels of inelastic deformation under lateral loads, implicit in ductility values, is dependent on the material and detailing used. For the ductile behaviour of beam–column joints, a considerable amount of lateral reinforcement is necessary. An experimental investigation is presented on the use of steel fibre reinforced concrete (SFRC) to provide ductility in a beam–column joint even after the increase in hoop spacing of lateral ties. Six one-third scale exterior beam–column joints were tested under reverse cyclic loading. The SFRC beam–column joint contained volume fraction of 1·5% steel fibre for all variable hoop spacing. The results were compared and evaluated with respect to strength, displacement ductility, energy dissipation, specific damping capacity and stiffness. Experimental results reveal that a SFRC beam–column joint performs satisfactorily and improved joint behaviour is indicated. The results also indicate that a reduction in the number of lateral ties in the beam–column joint by the appropriate use of SFRC can be an alternative solution for avoiding conjunction of reinforcement.