Ultimate and post-ultimate behaviour of thin-walled cold-formed steel open-section members under eccentric compression. Part Ⅰ: Collapse mechanisms database (theoretical study)

摘要

The paper investigates the possibility to use the local plastic mechanisms to characterize the ultimate strength of short thin-walled cold-formed steel members subjected to eccentric compression and presents a database of local plastic mechanisms of failure for lipped channel section columns subjected to eccentric compression about minor axis. The background of yield line analysis related to thin-walled steel members is presented. Also, the buckling behaviour of examined members is briefly discussed. The geometries of the theoretical models of local plastic mechanisms for those members, for a wide range of applied eccentricities, are presented in detail. Comparative diagrams of equilibrium paths obtained from FE simulations together with post-ultimate curves derived via yield line analysis are shown based on developed mechanisms models. At the end, some conclusions concerning the applicability of presented mechanisms models for determination of load-carrying capacity of structures under investigation are derived.