CONCRETE-FILLED HSS CONNECTIONS

A novel method of reinforcement for welded-truss connections between hollow structural sections (HSS), in which the chord member is filled with concrete, is described. The behavior of concrete-filled T-, X-, and gapped K-connections is examined by means of tests on 31 filled and unfilled connections, and the effects of concrete filling on structural performance are established. It is shown that there is a significant improvement in strength for connections that have a branch member, or members, loaded in compression. Moreover, the strength of concrete-filled HSS connections can be adequately predicted by considering the bearing capacity of the confined concrete (under compression loading) or a subset of existing design expressions for unfilled HSS connections (under tension loading).