Consideration of Scale Effect in Reinforced Concrete Members Subjected to Shear Loading

This paper describes how, in most structural members, strength tends to decrease as the member size increases and this phenomenon is known as the scale effect. Many experiments investigating the impact of scale effects on reinforced concrete (RC) structures have already been conducted. However, since few laboratories have the capacity to test large-scale specimens, few experimental investigations have tested near full-scale RC members. This paper investigates the scale effect in RC members that are subjected to shear loading. Two different sized test specimens were prepared and tested. The results clearly indicate that the member strength decreases as its size increases. The Japanese building code, an empirically-based code with no scale effect parameter in the shear formulas, generates overly-conservative predictions for full-scale members. Using plane concrete monotonic compression strength data, a formula defining the shear strength of reinforced concrete members is proposed. Experimental results show that the proposed formula for computing ultimate strength agrees better with the experimental data than existing formulas.