Comparisons of Performance of Building Using Bright New And Old Rusted Rebar

Abstract

Reinforced cement concrete structure are the most common structures in India. The strength of structure depends mainly on two components i.e. concrete and steel rebar. One of the main constituent i.e. steel, changes its strength along with the changes in property of steel rebar irrespective of the types of steel, mainly due to rusting of iron i.e. formation of iron oxide by the reaction of iron and oxygen in the presence of water or air moisture. In the present study, experimental investigation has been done as to find the property of steel for the bright new rebar as well as for the old rusted rebar of a particular brand of steel rebar. The experimental result showed that the new bright rebar has ~ 50% higher yielding strength as compared to the old rusted rebar strength. The ductility of new bright rebar is having ~125% higher than the old rusted rebar. The material property of steel extracted from the experiment has been incorporated in Finite Element modelling of a particular building using SAP 2000. The building has been designed under the gravity load as well as uniform lateral load. The performance of building is found out through push over analysis in terms of load vs displacement. The ultimate strength of building using new rebar is around 60% higher than the strength of building with old rebar. The displacement capacity of building also differs significantly i.e. building with new rebar is having ~60% higher than building with old rebar’s. Overall, the steel rebars need to be protected from corrosion for the construction of structures.