Abstract: Concrete confined by stirrups has a greater ductility than unconfined concrete which is widely used in reinforced concrete (RC) structures and its behavior is a classic topic of discussion. Non-linear behavior of reinforced concrete is complex due to involvement of various heterogenic material properties and cracking behavior of concrete. It is very important to understand the response and failures of columns subjected to lateral loads in order to save lives and reduce thedamage to the building components. The failure prediction of reinforced concrete elements is usually carried out using experimental testing, and the observations are recorded only at critical locations due to restriction at the cost of testing equipment and accessories. To avoid the destructive testing, cost-cutting of materials and labor, the behavior prediction of reinforced concrete elements is typically carried out using numerical methods like Finite Element Method which responds well to non-linear analysis as each component possesses different stress-strain behavior.Keywords: Reinforced concrete columns, size effect, lateral loading, seismic analysis