Prediction model for catenary action of welded RWS connections using PVM link element

Abstract

A link element incorporating a nonlinear axial-shear-flexural (PVM) yield function is established for idealized beams with reduced web section (RWS), focusing on the static response when a column loss is triggered. The proposed model is considered in terms of the lowest level of model reduction, that is, axially restrained beams subjected to mid-span point loading (MPL) with boundary springs. A monotonic loading test was conducted on the perforated beams to calibrate the proposed model. The main features of the new approach include the consideration of the multi-surfaces concept and an anisotropic hardening rule is employed in the plastic hinge. The proposed model can predict the load–displacement relationship before the failure limit. The internal force evolution of the inner hinge is analyzed to determine the change in the load transfer mechanism of the RWS connection with rectangular openings. The numerical results show that the traditional equivalent rectangular opening method should be improved to reflect the large deformation response of the circular web opening beams. The proposed model can offer a practical tool for the progressive collapse design of steel frames with web opening beams under column removal scenarios.