Issue 78

S. M. Khalil et alii, Fracture and Structural Integrity, 78 (2026) 346-366; DOI: 10.3221/IGF-ESIS.78.20

Figure 20: Stiffener’s shape area effect showing von-Mises stresses at failure load.

C OMPARISON WITH I NTERNATIONAL DESIGN C ODES

T

o evaluate the existing design provisions with the examined stiffened closed-flange configurations, the ultimate load from the FEM (P FEM ) is compared to the web resistance as per EN 1993-1-5 [33] (P Code ) under localized patch loading. Both triangular and rectangular closed flanges with stiffener thicknesses of 4, 6, and 8 mm and under varying patch loaded length of 0, 75, and 150 mm are considered in the comparison. For EN 1993-1-5, the equation for patch load resistance for stiffened girders is given as   RD y F F M1 F = F χ λ / γ (1)

where:

F y = yield resistance, and is calculated as y

(2)

yw w y F= f t L





a 

y 2 L = S +2t 1+ m +m S f 1

L y = effective loaded length, and is calculated as

(3)

m 1 is a dimensionless parameter that takes into account hybridity, and m 2 is also a dimensionless parameter that considers the girder's web contribution, and are calculated as:

(4)

1 yf f yw w m = f b /f t



 2

2 w f m = 0.02 h /t

(5)

1

  χ λ = F F



1

(6)

  F

2

 

+ - λ

  Fo F Fo F 1 = 1+ α λ - λ + λ 2     

(7)

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