Modelling Studies of Retrofitted Anchorage System in Exterior Beam Column Joint by Supplementary Steel

Abstract

A Nonlinear finite element based ABAQUS modeling studies were conducted to evaluate the performance of exterior Beam Column Joint (BCJ) under quasi-static test loads. Six integrated BCJ models representing different configurations of beam reinforcement anchored in joint are verified by using a novel retrofitting technique called "Post Installation of Supplementary Anchorage" (PISA) by using headed bar as supplementary steel. The configuration of beam reinforcement anchored in column are described by straight bar,90 degree bend ,180 degree hook (confirming to design code IS456:2000) and single head, double head bars (confirming to ACI 318-19, ACI 352R-02 ) and 90 degree long bend of ductile detailing (as per IS 13920-2016). Two series (A&B) of integrated joint specimens representing conventional (series-A) and retrofitted anchorage (series-B) systems are modeled and tested by using ABAQUS software. The test parameters considered are configuration of anchorage system and presence of supplementary anchorage. The test variables representing nonlinear performance of retrofitted joint system are Von Mises stress conditions, Principal tensile stress, Moment-Rotation, Degraded stiffness, Crack mechanics and Damage index. The results shows good improvement of post failure conditions of exterior beam-column joint such as relocation of plastic hinge mechanism and failure mechanics of retrofitted joint system. Also the results validated with experimental program on typical specimens casted and tested. This study imparts useful information on implicit retrofitting methods applied by external means in exterior beam-column joint. It also promotes performance based design principles with viable construction practice.