Undercut and grouted anchors as post-installed shear reinforcement

The need for conservation in engineering has become apparent in the past several decades as a result of resource depletion, aging infrastructures, and diminishing real estate. In addition, many structures see increased loads due to building re-purposing; others simply do not meet the demands of modern code provisions. As a result, techniques to retrofit existing buildings are becoming increasingly important. This thesis investigates the use of post-installed undercut and grouted (rods grouted in place) anchors for strengthening reinforced concrete beams in shear. These techniques are especially useful when access to members requiring retrofit is limited. Experimental results are compared to the ACI-DAfStb shear database19,20 and to American Structural Design Code provisions. The results indicate that high strength anchors can effectively strengthen beams and achieve equivalent or greater deformation and load capacity as traditionally reinforced elements. However, precautions should be taken to avoid alternate anchor failure modes; a designer should validate that anchor yield can be achieved, or account for the possibility that post-installed anchors will not yield.