Development of Plastic Hinge Models for Corroded Reinforcement in RC Beams

Abstract

Earthquake can cause great amount of damage to humanity among all-natural hazards. In order to avoid collapse of building during major earthquakes, most of the multistoried buildings are designed and detailed to combine strength and ductility. To attain the required ductility, they need to be proportionally adjusted to ensure that in the event of a large earthquake, the beam swing failure mode takes precedence over the cylindrical swing failure mode. The designated area in the structure (called a potential plastic hinge) is designed to withstand inelastic deformation, while the rest of the structure undergoes elastic deformation. Dynamic performance of building is determined through these plastic hinges once yielding has occurred. Also, deformation capability of plastic hinge in RCC structure are dependent on quality of steel. Reinforcing steel bars have been corroded to different levels due to environmental effects in already existing structures. Further, corroded reinforcements will not allow the structure to behave as ductile moment resisting building during earthquake. Therefore, incorporating plastic hinge model of corroded RC beams to make sure weak beam- strong column behaviour is the base of this research to prevent collapse of RC structures during earthquakes. In this work, plastic hinge model of RC beam under flexure loading incorporating the effect of 10%, 20% and 30% corrosion in reinforcement bar has been attempted. Nonlinear behaviour of Reinforced Concrete structures is observed using developed plastic hinge model. The study of the effect of corroded old reinforcement is done on the plastic hinge parameters of RCC structures. For this, the effect of different grade of concrete and different reinforcement bar along with the condition of reinforcement (bars have been corroded outside the beam) on a RC beam is studied under flexure loading. The beams are simply supported under four-point loading to ensue flexure behaviour. The moment carrying capacity is increased when the concrete grade is increased.