Structural behaviour of FRP-confined concrete-encased cross-shaped steel columns

Over the past three decades, fibre-reinforced polymer (FRP) has gained wide applications in the strengthening and retrofitting of existing reinforced concrete structures. More recently, the use of FRP in combination with conventional construction materials (e.g. steel and concrete) to develop novel hybrid column forms for new construction has attracted increasing research attention. This PhD thesis presents the conceptual development and research on the structural behaviour of a novel type of hybrid columns, namely, FRP-confined concrete-encased cross-shaped steel columns (FCCSCs). An FCCSC consists of a square FRP outer tube, a cross-shaped inner steel section and concrete filled in between. This sectional configuration ensures that the concrete is very effectively confined despite the square shape of the column. In addition, the cross-shaped steel section serves as the ductile longitudinal reinforcement for loads in the two lateral directions and its possible buckling is constrained by the FRP outer tube and the concrete, leading to a column that is highly ductile...