Experimental Study on Beam- Column Joint with Fibres under Cyclic Loading

Abstract

In earthquake resistant design, it is important to ensure the ductility in the structure, i.e., the structure should be able to deform inelastically and dissipate energy without causing collapse. In frame structure, the bending moment and shear force are maximum in the junction area. So beam-column joint is one of failure zone. Among the beam-column joint, exterior joint behaves more critically than the interior joint during the occurrence of earthquake. Many researchers have done research on joints using different techniques, materials and introduced many repairing methods to enhance the resisting capacity of joints. From literature, it has been observed that Polypropylene and Steel fibres have enhanced many desirable properties of concrete. Hence, these fibrous materials can be introduced in these joints to enhance joint property. Polypropylene is a plastic polymer and Steel fibres are made from prime quality hard-drawn steel wire to ensure high tensile strength and close tolerances. Literature survey on these fibres does not reflect any prominent work carried out on beam-column joint using these fibres, particularly under cyclic loading. Hence, in the present research these fiber materials were used for beam column joint to observe the change/enhancement in the strength, stiffness, ductility and energy dissipation capacity of the joints. In the present work, three one third (1/3 rd) scaled beam-column joints have been caste with plain RC and RC fibres. All the specimen has been detailed by the provisions of IS: 13920 incorporating similitude requirements. The specimens were tested by applying cyclic load. The tests were conducted by using servo hydraulic actuator (MTS made) of 100kN capacity. The recorded data were plotted to draw hysteresis loop. The result were compared in various plot like envelope curve, stiffness, energy dissipate and ductility. It was observed that performance of fibre specimens in term of all the above parameters were better than the plain specimen.