Structural performance of composite base column connections

ABSTRACT: The present paper provides the results of a comprehensive experimental research program carried out on partially encased composite steel-concrete columns connected to the foundation block through traditional (bolted steel end plate) and an innovative system employing a socket type system. Experimental tests under monotonic loads show that the structural behaviour of the traditional connection is significantly influenced by the response of the anchorage bolts. The latter cause large fixed end rotations and exhibit limited energy dissipation. Conversely, innovative composite base column connections with socket systems possess adequate inelastic deformations and energy absorption. Furthermore, the use of socket-type connections is beneficial for the spreading of inelasticity at the base of the composite columns without damage localization on concrete and interface components. It can thus be argued that the innovative connection assessed in this study is a viable solution for applications in framed structures fulfilling capacity design requirements, e.g. structural systems in earthquake prone regions.