Parametric Study to Decide the Optimal Rebar Grade for Flexural Members

The growing interest of using higher strength reinforcing steel for certain applications within the reinforced concrete industry is driven primarily by relief of congestion; particularly in buildings assigned a high seismic design category. Construction efficiency can be improved by high strength bar or combined with high strength concrete which allows reinforced concrete to be used in more demanding applications. High grade steel generally increases the cost as well allows smaller concrete member which creates a problem of placement of reinforcement. Therefore there is a need to study the better option between lower quantity of high grade and high quantity of lower grade. This paper presents the parametric study to see the effect of beam span and member sizes on the results obtained in design of simply supported flexural members using different rebar grades, such as Fe415, Fe500, Fe550 and Fe600 in terms of crack width and member deflections for mild and moderate exposure conditions. It was observed that detailing plays vital role in cost saving and crack width limit governs final steel requirement in moderate exposure condition. Cost analysis was also performed for different grades and Fe500 is found optimum grade.