Development of engineering methodology for calculating the plane bending stability of an I-beam

Introduction . In the ongoing code of practice for steel structures, the methodology for calculating the plane bending stability of beams is undoubtedly regarded as its’ weak point. Due to the limitations of the method, the calculation results often do not agree with numerical calculations and studies. The normative calculation method uses a three-factor formula, thus providing for the calculation of simple cases only. While the use of steel structures for various needs is increasing, design codes remain behind the present demands thereby often failing to follow the calculations and provide sufficient answers to questions. Apparently, the reason lies in the fact that there are no modern developments in the field of stability theory. No previous results are revised and no attempt is made to improve the current theory. Moreover, in the case of beam theory, a dead end seems to have been reached. Aim . To develop a more advanced approach in resolving the bending-torsional loss of beam stability, as well as to make a unified equation of bending stability coefficient. Materials and methods. The bifurcation problem in V.Z. Vlasov theory for thin-walled rods was revised, and a formula in deformation theory was developed based on Merchant’s formula, exponential and degree functions. Results . An improved methodology for calculating the stability of the plane bending form of a beam, as well as a new set of coefficients and equations for solving the problem are proposed. These solutions complement and extend SP 16.13330.2017. Conclusions . The methods and standards for the calculation of steel structures in terms of the overall stability of beams can be extended to comply with contemporary requirements.