Structural behavior of expanded rib steel bars used in reinforced concrete beams

Conventional headed rebar is advantageous in reducing embedment depth and simplifying construction; however, they are subject to concentrated stresses at the anchor point which can lead to failure of the structural element. To alleviate the stress concentration and avoid failure, rebars with numerous expanded ribs are proposed herein. The effects of expanded rib bars were investigated by comparing a jointed specimen with an expanded rib bar joint to a specimen with a conventional headed bar and an unjointed continuously reinforced specimen using the four-point bending test. The maximum strength, displacement ductility, cracking analysis, and rebar strain were recorded and analyzed. In terms of structural performance, the expanded rib bars outperformed the conventional headed bars and were equivalent to the unjointed continuously reinforced sections. •Rebars with numerous expanded ribs are proposed to reduce stress concentration.•Effects of expanded rib bars are compared in various specimens.•Maximum strength, displacement ductility, cracking, and rebar strain are analyzed.•Expanded rib bars are found to outperform the conventional headed bars.