Bolts gauge effect on the face bending behaviour of concrete-filled hollow section for hollo-bolted connections

This paper investigates the effect of bolt gauge on the face bending behaviour of concrete-filled Square Hollow Sections (SHS) in Hollo-Bolted connections. A set of full-scale experiments were undertaken to examine the effects of varying the bolt gauge on the SHS face bending behaviour while controlling all other parameters. Typical experiment involved one row of two bolts pulled out of concrete-filled SHS. A special dummy bolts were manufactured to the exact size and geometry of open Hollo-Bolts, and were used in the experiments to remove the influence of any deformation associated with the real Hollo-Bolts, and isolate the face bending behaviour. Non-contact video-based equipment was used to record the SHS face deformation. This deformation is recorded as force-displacement relationship which is commonly used to represent the structural behaviour of similar components, and typically defined by initial stiffness, yield force and post yield stiffness. Across the range considered in this investigation, it was found that varying the bolt gauge to SHS width ratio have a significant effect on the concrete-filled SHS face in bending component. Both the initial stiffness and the yield force of the component were found to increase with the increase of the bolt gauge. The Post-Yield stiffness was not affected by the change in bolt gauge