Experimental Evaluation of Tension and Shear Capacities of New Headed Cast-in Specialty Inserts in Cracked Concrete

Abstract

Headed cast-in specialty inserts are often developed and employed for their improved constructability and time-saving benefits over traditional cast-in and post-installed anchors. Their acceptance criteria (AC 446) were established by The International Code Council Evaluation Service. However, previous research on the behavioral characteristics of headed specialty inserts is rare. This study investigates the performance of a newly developed insert anchor for use as an earthquake-resistant anchor for fire protection systems and suspended lightweight piping. Firstly, three cyclic tension tests of the specialty insert with a threaded rod were conducted in accordance with AC 446. These tests resulted in all experimental subjects achieving the target strength without defects. Subsequently, monotonic tension and shear tests of the insert anchor in cracked concrete were performed five times each to assess the tensile and shear capacities of the new insert anchor. The results were compared with the nominal strength determined by the anchor design equation provided by the ACI 318 for cast-in headed anchors, finding that the latter adequately approximates the concrete breakout strength of the new insert anchor in tension but underestimates the concrete pryout strength in shear. Based on the measured breakout failure surface angles, a projected area of the failure cone of the corresponding anchor with a relatively large head size is proposed.