Effect of Confinement on Load – Moment Interaction Behavior of Reinforced Concrete Column

Abstract

Provision of ductility is of particular importance in the design and detailing of reinforced concrete structures subjected to seismic loads. To fulfill this requirement, the recent design code specified the use of transverse reinforcement or stirrups in the structural member such as column. However, the design is based on the simplified stress block of unconfined concrete, and does not account for the strength gain due to the presence of confinement. To investigate the effects of lateral confinement on column capacity an analytical study is carried out. In this study the design stress-strain diagrams for confined concrete are developed by considering different proposed confined models and its effect on column capacity is studied in terms of load – moment interaction diagram of column. The presence of lateral reinforcement expands the interaction diagram of the column particularly when it is in the compression-controlled region