Anforderungen an Stahl- und Verbundknoten bei Stützenausfall in einem Rahmentragwerk

Requirements on steel- and composite joints for the load case column removal.

Local failure in a structure (e. g. sudden column loss due to impact or explosion) may lead to progressive collapse propagation of the global structural system resulting in a total collapse. To avoid progressive collapse initiated by local damage a redistribution of force from the damaged part of the structure has to be enabled by alternate load paths. Activation of alternate load paths by change of the bearing mechanism from pure bending state to more or less pure membrane state is a measure that is only possible by allowing large deformations resulting in high deformation requirements for the joints.
In the course of an European RFCS research project ductile joint solutions have been developed to improve the robustness as characteristic of the structure. Main focus of the joint design was to obtain the required deformation capacity for accidental design situations mainly from ductile joint and cause at the same time only few additional material and fabrication costs for the joints. As a result semi-rigid and partial-strength joint solutions have been chosen. Objectives within the project were to determine requirements of the joints concerning deformation capacity as well as M-N-resistance to enable the activation of catenary action for the load case notional column removal.