Tensile Behavior of Small Screw Anchors under Cyclic Crack Openings

Small-sized anchors (typically 6 mm [0.24 in.]) are commonly used for nonstructural applications. There has been increasing demand for seismic performance of fastenings for nonstructural applications; however, there have been no 6 mm (0.24 in.) size screw anchors with seismic prequalification for large crack width. This study investigated the feasibility of small-sized screw anchors to perform under tension loading in crack widths of up to 0.8 mm (0.03 in.). Tension tests were conducted in cracked concrete with varying crack widths (0.3, 0.5, and 0.8 mm [0.01, 0.02, and 0.03 in.]) under monotonic, pulsating, and varying crack width load protocol. Based on the findings of this study, 6 mm (0.24 in.) screw anchors exhibited load drop and slip behavior in large crack width during the residual capacity test, even for anchors with a deeper embedment. Finite element analysis was conducted to investigate the feasibility of a larger-sized thread width to perform in 0.8 mm (0.03 in.) crack width.