Reliability of a steel member in case of loss of local stability of a web

Introduction. Thin-walled steel beams are widely used in the construction of buildings and structures. Steel beams with thin webs are popular due to their efficient bending performance, although the issue of local stability becomes relevant. The ana­lysis of models, simulating resistance to shear and local loading pursuant to various regulatory documents, shows that calculation formulas are complex in most cases and have a limited scope of application, while resistance values, obtained using different methods, are vastly different. Materials and methods. The accuracy and essential areas of improvement of a resistance model can be identified by analyzing the numerical characteristics of model simulation uncertainties and comparing them with the experimental data. Results. The author has identified statistical characteristics of the model uncertainty. Values of reliability factors, that ensure the target level of reliability, are identified with account taken of the variability of basic variables and the uncertainty of resis­tance models. Conclusions. These values are indicative of the conservative nature of the model under consideration, which confirms the need to develop a design method on the basis of FEs of models that will take account of design features of the member under consideration and ensure more accurate and universal solutions. Their reliability is guaranteed by unified requirements for FE models, followed by their verification by the experimental data and reliability parameters applied to check the limit states. The article also offers a method for identifying the value of the reliability factor for a nonlinear load-bearing model, taking into account the statistical characteristics of basic variables included into the resistance model.