Novel Adhesive Anchoring System Through Engineered Interface

Abstract

This report describes a study of an innovative adhesive anchoring system. The weak link in the load transferring path of adhesive anchors is at adhesive-concrete (A-C) interface; hence, the innovation is about creating threads/grooves in drilled holes in concrete before the holes are filled with adhesive and anchors are installed. The new anchoring system is expected to improve the robustness of A-C interface and the consistence of adhesive anchors. The new adhesive anchoring system was verified in this study using both unconfined and confined pullout tests in uncracked concrete. The tests were divided into to two groups, one using traditional adhesive anchors and the other using the new adhesive anchors, considering two anchor sizes and three hole-cleaning conditions that represent typical practices. Finite element (FE) analyses using ABAQUS were also conducted to simulate the behavior of the adhesive anchors under tensile loading. The nonlinear analyses incorporating surface-to-surface contact, concrete damaged plasticity and nonlinear spring models were found suitable to capture the global and local behavior of the adhesive anchors with pullout bond failure. The test results and analyses showed that the new adhesive anchors greatly improved the capacity and consistence of adhesive anchors. Meanwhile, further studies are needed to validate the benefit of the proposed adhesive anchors under a variety of conditions such as sustained loading and in cracked concrete. It is also critical to develop a feasible tool to facilitate the implementation.