Effects of loading conditions on behaviour of semi-rigid beam-to-column composite connections

In the design and analysis of moment resistance framed structures, the internal joints are generally modeled as two separate connections with independent characteristics. However, in the case of composite frames, the interaction between two connections located on both sides of the column can be significant, especially under the action of anti-symmetrical moments. In this paper, the experimental results of four composite beam-column internal joints are presented. The specimens were constructed using either flush endplate connections or partial depth endplate connections. Three different loading conditions were considered, namely, (1) hogging moment developed at connection of one side of the joint; (2) sagging moment developed at connection of one side of the joint; (3) hogging moment developed at one connection and sagging moments developed at the other connection simultaneously. Test results indicate that the connection subjected to loading case (1) or (2) has the moment capacity over 20% higher than the corresponding value developed under the loading case (3). Finally, the experimental results are compared with the calculations of an advanced component-based model. It is demonstrated that the analytical results were in good agreement with the experimental results.