Influence of rebar couplers on the cracking behavior of reinforced concrete beams

Abstract

Mechanical connections of rebars are widely used and demonstrated high effectiveness in reinforced concrete structural elements, but the differences in the performances of different connection methods in reinforced concrete beams from the perspective of adhesion, bending, and load transfer are rarely documented. In addition, existing rebar connections are large and may lead to local cracking because of their size. In this study, we investigated the use of compact mechanical couplers by pull-out tests and bending tests of full-scale reinforced concrete beams. For pull-out tests, the influence of the couplers position in concrete was studied. Different rebar configurations were tested for beams: continuous, with a covering, or connected with compact mechanical couplers. The nonlinear behaviour of beams was analysed under monotonic and cyclic load conditions. The overall behaviour of beams is discussed in terms of load–displacement curves and concrete cracking distribution. To study the local behaviour, digital image correlation was set up, allowing to monitor strain distribution and crack opening.Experimental results show no significant impact of the compact couplers on the global or local behaviour of reinforced concrete beams compared to the beams using continuous rebars: failure load, overall stiffness, and crack distribution are similar, in the uncertainty range of tests. The regulatory calculation of crack openings and spacing fits the experimental results for most of the studied cases.