Experimental investigation of bolted hollow section splices using unstiffened circular end plate

Moment resisting connections are widely used nowadays in different applications. The use of circular hollow sections (CHS) has increased due to its aesthetic appearance and good mechanical properties. Attention should be given to their connections under different loading conditions to achieve greater flexibility for their use. This research investigates the behavior of bolted CHS splices with solid circular end plates under pure bending moment that allows the use of CHS as long flexural members. Eight connections were tested and corresponding finite element models were constructed. The finite element models were verified against the experimental results and shown to provide acceptable agreement in terms of both ultimate moment capacity and load-displacement curves. Three modes of failure were observed where the first is pure bolt failure, the second is pure end plate yielding while the third is a combination of the two modes where end plate yielding is accompanied by bolt failure. Stiffness was also observed and was found to be greatly affected by the thickness of the end plate. Increasing the number of bolts in the end plate did not have a substantial effect on the connection stiffness but it increased its moment capacity. Contact forces between the two end plates were observed and the axis of rotation can be conservatively considered to be tangent to the CHS on its compression side. This finding can be used for end plate yielding analysis. [Display omitted] •An experimental program of eight specimens is carried out for CHS splices.•Different geometrical configurations are considered in the program.•Different modes of failure are observed in the tested specimens.•Effect of different parameters on the behavior of the splice is studied.•A finite element model is constructed and verified against the experimental results.