Anchorage of Beam Bars with 90-deg Bend in Reinforced Concrete Beam-Column Joints

Based on the author's previous tests, failure modes of beam bar anchorage with 90-degree bend used in reinforced concrete beam-column joints were classified into three types: a side split failure, a local compression failure and a raking-out failure. In order to clarify the raking-out failure, the least understood of the modes, column type specimens with beam bars with 90-degree bend in the beam-column joint were tested under pull-out loading at the bars. The specimen variables were: development length, column depth, lateral reinforcement ratio, spacing between beam bars, concrete compressive strength. From the test results, influence factors on the raking-out failure mode were discussed and an equation evaluating anchorage strength was proposed.