BEAM-COLUMN JOINTS REINFORCEMENT DETAILING ADEQUACY IN CASE OF A CORNER COLUMN LOSS-NUMERICAL ANALYSIS

Abstract

THIS STUDY INVESTIGATES THE BEHAVIOR OF REINFORCED CONCRETE (RC) BEAM-COLUMN JOINTS AT THE CORNER PANEL AFTER A GROUND CORNER COLUMN LOSS SCENARIO. THE DUCTILITY OF A FRAME IS DEPENDENT ON THE DUCTILITY OF ITS COMPONENTS, PARTICULARLY ITS JOINTS. DEFICIENCY IN JOINTS PERFORMANCE CAN BE RELATED TO AN UNEXPECTED EVENT. FOR EXAMPLE, THE REMOVAL OF A GROUND CORNER COLUMN TURNS THE JOINT ABOVE INTO AN INVERTED KNEE JOINT, AND ALSO INVERSES THE DIRECTION OF THE RESULTED BENDING MOMENTS IN THE ADJACENT EXTERIOR AND INTERIOR JOINTS. THROUGHOUT THIS WORK, THE EFFECTS OF THESE CHANGES ARE EVALUATED NUMERICALLY USING DIFFERENT MODELING TECHNIQUES CONSIDERING BOTH SEISMIC AND NON-SEISMIC REINFORCEMENT DETAILS. NUMERICAL SIMULATIONS OF STANDARD AND SUB-STANDARD JOINTS THAT WERE VERIFIED AGAINST EXPERIMENTALLY TESTED JOINTS ARE ALSO PRESENTED. JOINT MACRO MODELS ARE DEVELOPED USING THE OPENSEES PLATFORM. THESE NUMERICAL MODELS ARE THEN USED TO SIMULATE THE SUBSTANDARD BEAM-COLUMN JOINTS APPEARING IN RC FRAMES AFTER GROUND CORNER COLUMN REMOVAL.  MOREOVER, STRUT AND TIE MODELS (STMS) WERE DEVELOPED FOR A SUBSTANDARD KNEE JOINT TO VALIDATE THE OBTAINED NUMERICAL RESULTS. THE APPLICATION OF THE DEVELOPED NUMERICAL MODELS ALLOWS TO IDENTIFY THE EVOLUTION OF A JOINT’S CAPACITY IN FUNCTION OF ITS REINFORCEMENT DETAILING. THE ANALYSIS SHOWS THE SUITABILITY OF SEISMIC DETAILING FOR EXTERIOR AND INTERIOR JOINTS AND ALSO A DECREASE IN THE INVERTED KNEE JOINT RESISTANCE AND THIS CAN BE RECOVERED BY ADDING I) MORE CONFINEMENT TO THE JOINT PANEL ZONE OR II) JOINT VERTICAL STIRRUPS. AN INCREASE IN THE DEGREE OF CONFIDENCE IN THE NUMERICAL RESULTS IS ACHIEVED BY REPRODUCE SIMILAR BEHAVIOR USING DIFFERENT ANALYSIS METHODS.