Effect of Concrete Infill and Slenderness on Column-Face Component in Anchored Blind-Bolt Connections

Abstract

Previous research on blind-bolted connections to hollow columns have provided a wealth of experimental data but little information on parametric analytical models to guide their design. One of the connection components that requires further understanding is the column-face bending. This paper presents the results and evaluation of experimental tests and finite element analyses for the bending behavior of the column-face component. Tests were conducted on full-scale connections to investigate the effect of concrete type and strength on the component. The results demonstrated that concrete strength has a direct influence on component strength and stiffness. The increase in concrete strength correlated with a significant increase in component strength. The increase in component stiffness was less significant, and is found to be limited by the column slenderness ratio (width/thickness). Slenderness ratio limits were defined beyond which the increase in concrete strength has no effect on component stiffness. A formula for evaluating the confinement effect on the concrete infill is proposed. The strength and stiffness of the component were not affected when using self-compacting concrete, but the use of lightweight concrete reduced both strength and stiffness. The failure mode of the component is bolt anchorage failure followed by a complete yielding of the column face plate around the bolts.