The effects of partial shear connection in composite flush end plate joints Part I — experimental study

The experimental results of partial shear connection composite beams subjected to hogging bending have been previously reported. An extension to this work which considers the presence of a semi-rigid, partial strength connection is described herein. Five sub-assemblages of cruciform composite joints that simulate the internal region of a semi-continuous frame were tested. The joints were constructed using a novel approach of blind bolting a flush end plate to concrete-filled square hollow columns. Apart from the level of shear connection, the other parameter varied was the reinforcement area. In addition, a bare steel joint was also tested to act as comparison specimen. Based on the experimental results, the intrinsic behaviour of the joints in terms of strength, stiffness and ductility was assessed. It was further affirmed that by lowering the levels of shear connection, the rotation capacity of the composite joints was enhanced with only a slight compromise if the stiffness and moment resistance. A notable effect on the connection behaviour was also observed by varying the reinforcement levels. The outcomes clearly affirmed the benefits of partial shear connection in contributing the additional flexibility to increase the joint ductility, which is extremely advantageous for plastic design purposes. In view of this, the current restriction of providing full shear connection design within hogging moment regions of continuous and semi-continuous structures could be relaxed.