Localization and Size-Dependent Response of Reinforced Concrete Beams

Abstract

This paper describes an experimental investigation conducted to determine whether the flexural response of reinforced concrete beams is size (length) dependent. 16 normal- and high-strength concrete beams were tested with 4 different constant-moment zone lengths and 2 different reinforcement ratios. Closed-loop control was used to obtain post-peak behavior, which allowed additional information about the failure mechanisms to be obtained. Results indicate that damage localization occurs in the compression zone, and the size of the damage zone is constant between specimens of different size. Evidence of strain-softening behavior could be seen by comparing local and global strains. While moment-carrying capacity of different size beams was relatively constant, the average strain at yield and maximum moment was observed to be slightly dependent on specimen length. The overall ductility of the beams was dependent on the constant-moment zone length, with larger specimens demonstrating a more brittle response.