EFFECT OF LATERAL REINFORCEMENT RATIO ON STRENGTH AND DUCTILITY OF RC COLUMNS

Abstract

In this paper, effect of lateral reinforcement spacing or ratio on the cyclic behavior of reinforced concrete columns is analytically investigated. The finite element analysis (FEA) is performed using computer software VECTOR. Two types of RC columns, i.e., short and long columns were modeled with varying lateral reinforcement rations such as 6 mm bars placed at 200 mm spacing (Type-1) and 6 mm bars placed at 75 mm spacing (Type-2). The RC Columns with Type-1 reinforcement details represent the non-ductile columns that are mostly found in the buildings of Thailand. In FEA plane stress rectangular elements were used for the modeling of reinforced concrete. Smeared cracking approach was considered in concrete and steel over the element. Finite element analysis (FEA) results indicate that performance of RC short columns with Type-1 reinforcing details is very poor against lateral loading with the development of significant cracks at very low drift levels. Whereas the behavior of RC short columns with Type-2 reinforcement were observed highly improved in terms of crack pattern, fracture mode, ultimate load capacities and ductility ratio as compared with non-ductile columns. However; the increase of lateral reinforcement ratio in long columns is found not effective to enhance ductility against lateral displacement.