A Study on Strength and Ductile Behavior of Beam-Column Joints Using Hybrid Steel Fibres

摘要

This research work deals about the strength and ductility characteristics of the interior and exterior beam-column joint in addition to the hybrid steel fibres. From the past earthquake studies about the interior and exterior beam-column joint concluded that the failure of the beam-column joint mainly happens due to the reduction of its moment carrying capacity and shear strength during a severe earthquake. This may be due to reinforcement provided in the junction and concrete which behaves as brittle materials because of the less ductile in nature. In this study, totally fourteen sets of the beamcolumn joints which have seven interior beam-column joint and seven exterior beam-column joints were cast for two-bay five-story structures. Four sets of exterior beam-column joints which had a percentage of steel fibres as 0%, 0.75%, 1%, 1.5% individually were designed as per IS1893code procedures and detailed based on IS 13920 recommendations. Three sets of the exterior beam-column joints which contained the percentage of steel fibres as 0.75%, 1%, 1.5% were designed as per IS 1893 code provisions and detailed using IS 456 recommendations. Similarly, seven sets of the interior beam-column joint sub assemblages were cast as above mentioned. The model was developed by considering the 1/5th scale of the prototype and was tested under forward cyclic loading. The loading frame was used to impart the cyclic loading to examine the behavior of the beam-column joints in terms of load-carrying capacity, deflection, ductility, stiffness degradation and energy observation. Subsequently, the linear regression model was developed to predict the deflection, ductility factor, stiffness factor and Energy absorption in a beam-column joint using the Levenberg- Marquardt Optimization (LMO) algorithm in Matlab. The study concluded that increased of energy absorption capacity and ductility properties of the interior and exterior beam-column joint as a result of the provision of 1% of the steel fibres and detailed reinforcement as per IS 13920. Thus, the experimental results indicated that fibre reinforced concrete is an innovative solution to conventional confining reinforcement.