On the SP 16.13330.2017 standard stability calculation of I-type bending elements with constant and variable cross-sections

Abstract

Introduction. The current Russian standards for steel structures, including the SP 16.13330.2017, contain rather limited material in terms of calculating the stability of bending elements. Moreover, these documents provide no information on the calculation of variable cross-section bars for longitudinal and transverse bending, as well as for the stability of such elements. Claimed analytical methods for solving stability problems can offer ever more convenient solutions in addition to numerical analysis.

Aim. To develop a methodology for calculating the stability of bending elements with constant and variable I-sections; to improve the code of rules for steel structures in terms of arch stability.

Materials and methods. The present study includes the determination of coefficients accounting for the variability of the beam cross-section along the length; the Bubnov-Galerkin analytical method is used to consider the effect of the bending moment gradient. An alternative representation of bending-torsional beam characteristics takes into account the height effect of point load application. The obtained analytical solutions are compared in LIRA-SAPR and ABAQUS software packages.

Results. The performed analytical study offers a set of additional coefficients and formulas to support the development of a technique for calculating the stability of bending elements. The solutions are in line with the SP 16.13330.2017. The results of the numerical analysis confirm the obtained analytical solutions.

Conclusions. The present theoretical study has shown the possibility of improving the existing method for calculating the total stability of beams. The paper proposes a simple idea of regrouping the bending stability coefficient and making it deterministic for many cases including beams with a variable web height.