Behaviour of Bolted Pipe Splices with Circular Pattern

Abstract

Moment resisting connection are widely used nowadays in different applications. The use of circular hollow sections (CHS) have 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 its use. CHS splices can be achieved either using a ring flange or a solid end plate. This research investigates the behavior of the bolted CHS splices with solid circular end plates under pure bending moment that allows the use of CHS as long flexural members. As the study focuses on small-to-medium diameters, number of bolts considered are 6, 8 and 10 bolts to fulfill code requirements for bolt spacing. Eight connections are experimentally tested and the corresponding finite element models are constructed. The finite element models are verified with the experimental results and showed acceptable agreement in terms of both ultimate moment capacity and load-displacement curves. Three modes of failure are 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 plastifies accompanied by bolt failure. Stiffness is also observed and is found to be greatly affected by the thickness of the end plate. Increasing the number of bolts in the end plate does not have such significant effect on the connection stiffness while it increases its moment capacity. Contact stresses between the two end plates are observed and the axis of rotation can be conservatively considered tangent to the CHS at its compression side. This concept can be considered for end plate yielding analysis used in the mathematical model developed through the study.