Buckling resistance of longitudinally stiffened panels with closed stiffeners under direct longitudinal stresses

Abstract

The buckling behaviour of panels may be determined according to EN 1993-1-5 [1]. Most of the design rules relating to stiffened panels in EN 1993-1-5 were derived on the basis of opensection stiffeners. Several recent investigations have shown that the application of the design rules according to EN 1993-1-5 considering the torsional stiffness of the stiffeners may overestimate the resistance of the panels. Therefore, the recent Amendment A2 to EN 1993-1-5 states that the torsional stiffness of stiffeners should generally be neglected in determining critical plate buckling stresses. In addition, prEN 1993-1-5 [2] provides rules for considering the torsional stiffness of stiffeners. However, in this article it is shown that even the rules of prEN 1993-1-5 are not sufficient to overcome the safety deficiencies. The article focuses on the investigation of the buckling behaviour of stiffened panels with closed-section stiffeners subjected to constant longitudinal compression stresses. Improved rules have been developed that allow to consider the torsional stiffness of the stiffeners. Based on an extensive numeri cal parametric study, a new interpolation equation be tween column-and plate-like behaviour is proposed. In comparison to [3], the investigations have been extended to the effec tive width method. They show that the proposal provides a safe and economic solution for the reduced stress method and the effective width method when considering the torsional stiffness of stiffeners by calculating the critical plate buckling stresses.Keywords bridge design; plate-like behaviour; column-like behaviour; stiffened panel; longitudinal; reduced stress method; effective width method; torsional stiffness of stiffenerThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Analytical and numerical calculation of the buckling stress for panels with closed‐section stiffeners

“…If we assume a buckling shape with one half-wave in the transverse direction (n = 1), the buckling coefficient kσ,p is a function of m, α and the nondimensional parameters δ, γ and θ of the stiffener. Finally, by minimizing the function (11), kσ,p can be defined in two branches, the first part corresponding to the value of kσ,p for m = 1 and the second part representing the minimum value of the function:…”

“…If the deformation was greater than 0.5, the buckling mode was defined as the global buckling mode. More information on the methodology of the global buckling identification can be found in [11]. [6,11] 4…”

“…More information on the methodology of the global buckling identification can be found in [11]. [6,11] 4…”

“…Finally, both approaches to determine σcr,p, namely the newly proposed analytical approach and the numerical approach, are used to calculate the ultimate resistance of plates according to the new procedure from FprEN 1993-1-5 [7] and compared with the GMNIA results from [6].…”

Buckling resistance of stiffened panels subjected to constant transverse compression stresses

“…New investigations [4], [5] concluded that the torsional stiffness of closed longitudinal stiffeners should be neglected in the calculation of critical buckling stresses to achieve safe results. Pourostad [6] proposes a new interpolation formula for the EN 1993-1-5 buckling design to consider the torsional stiffness of stiffeners, see Equations ( 2) and (3). The proposal in [6] is derived based on longitudinally stiffened panels under direct longitudinal stresses.…”