Stability of prestressed stayed I-section steel columns: Zones-based and intelligent design considering local buckling

The instability and design methods of prestressed stayed I-section steel columns are investigated with local buckling taken into accounts. Mechanical tests on this system are conducted, and a validated finite element modelling is developed. The conventional prestressing zones are revised through introducing the effective crosssection from EN 1993-1-5. It is found that the nonlinear stability and actual optimum prestress of this system are strongly linked to dominant global buckling modes, and for the cases with more significant local buckling, the buckling and post-buckling behaviour are less sensitivity to stay size, crossarm length and prestressing levels. Explicit expressions for designing the load-carrying capacity of this system are proposed based on the revised prestressing zones, and an artificial neural network (ANN) model for predicting ultimate loads is also developed. The comparison between these two design methods shows that the performance of the ANN model based design method is more robust and satisfied.