Development of Post-installed Headed Bars Embedded into Grouted Holes with Enlarged Ends

To secure good quality post-installed anchors with a relatively short anchorage length and sufficient pull-out/shear resistance, an anchoring method with enlarged diameter at the end of drilled holes has been developed. Anchors were provided with head plates and fixed into the enlarged holes using non-shrinkage high-strength cementitious grout. Pull-out and shear preliminary tests were conducted to investigate the behavior and evaluate the strength of such anchors set in concrete. Furthermore, an evaluation method, based on the Japanese recommendations for design of composite constructions, was proposed. The evaluated pullout and shear capacities of all tested anchors designed to fail by steel yielding ensured sufficient safety margin as to test results, whereas those of some anchors designed to fail by concrete cone breakout should be reduced.