LAUSR

Abstract When bolted connections are preferred and concrete-filled steel tubes are chosen as the columns, blind bolts can be used instead of ordinary structural bolts to eliminate the need for access to the inside of the tube to tighten the nut. In order to achieve a stiff and strong connection, a modification of the blind bolt has previously been made by extending the bolt shank into the concrete and inserting another nut at the end of the bolt shank, the so-called headed anchored blind bolt (HABB). A further advance has been instigated here to achieve the maximum possible pull-out stiffness of this type of blind bolted connection by installing an additional head at the middle of the bolt shank anchor, called the first embedded head. This paper reports the results of an experimental investigation of the cyclic behaviour of individual double headed anchored blind bolts (DHABBs), which have two embedded heads, within concrete-filled circular hollow sections (CFCHS) using plain and steel fibre reinforced concrete (SFRC). After achieving a good agreement between the experimental and FE results, the relative contributions to the pull-out force of the first embedded head, end embedded head, and the tube wall were derived. In addition, parametric studies have been conducted using FEA to consider the influence of the concrete strength and type of concrete, the D / t ratio of the steel tube, the removal of the first embedded head, the location of the first embedded head, and the blind bolt diameter.