Tensile Behavior of Cast-in-Place and Undercut Anchors in High-Strength Concrete

Abstract

This paper deals with the pullout capacity, the failure cone geometry, and the load deformation behavior for both cast-in-place and post installed undercut anchors embedded in high-strength concretes with compressive strengths of 7500 and 12000 psi. Cast-in-place anchors where embedded at depths of 4, 6, and 8 in., whereas the undercut anchors were only embedded at a depth of 8 in.. Shallow cone failure angles, ranging from 21 to 28 deg, occurred consistently for all cases regardless of embedment depth, contradicting the 45 deg cone assumed in many design methods. For cast-in-place anchors, current design methods (such as CCD, ACI 349, TVA, TRW-Nelson) over predicted anchor pullout capacity. Over prediction of pullout capacity increased with increasing concrete compressive strength. For the post-installed anchors, the CCD model under predicted anchor pullout capacity, whereas the ACI model over predicted anchor pullout capacity.