Plastic Deformation Capacity of H-Shaped Beams Reinforced by End Stiffeners

Abstract

The H-shaped beams reinforced by the horizontal stiffeners at the beam end can be expected improvements in the plastic deformation capacity. The purpose of this paper is to show plastic deformation capacity of the H-shaped beams and to clarify the optimal stiffener shape. For this purpose, authors conduct cyclic loading tests on the several parameters ( length of the beam, thickness of the web and length, width and thickness of the stiffener ), and confirm the distinction of plastic deformation capacity related to the stiffener shape. Furthermore, in addition to the loading tests, by using the numerical analysis and the energy method, authors fix the required rigidity and the required length of stiffeners according to the demanded performance.

Estimation of plastic deformation capacity for I‐shaped beams with local buckling under compressive and tensile forces

“…In addition, under compressive axial force, the preliminary analyses confirm that the wavelength of the local buckling becomes shorter, and the out-of-plane deformation due to the lateral-torsional buckling tends to be larger than that under no axial force. Therefore, the position of constraint for out-of-plane deformation is determined as 0.25L, which is nearer to the fixed end 20 In Figure 12A, H-300 9 150 9 6 9 9 (No. 2), which possesses a larger flange width, originates local buckling only, regardless of the existence of out-of-plane constraint, whereas H-300 9 125 9 6 9 9 (No.…”

“…In Figure (A‐2) and (B‐2), the out‐of‐plane deformation is constrained at 0.25 L from the fixed end. With regard to the position of the out‐of‐plane deformation, it can be assumed to be 0.3 L to 0.4 L based on the optimum bracing position, which switches the first buckling mode to the secondary mode, derived by Kimura and Yoshino; previous cyclic loading tests on I‐shaped beams collapsed with the local buckling in the tests conducted by Ikarashi et al under no axial force.…”

“…In addition, under compressive axial force, the preliminary analyses confirm that the wavelength of the local buckling becomes shorter, and the out‐of‐plane deformation due to the lateral‐torsional buckling tends to be larger than that under no axial force. Therefore, the position of constraint for out‐of‐plane deformation is determined as 0.25 L , which is nearer to the fixed end than the optimum bracing position by Kimura and Yoshino and cyclic loading tests by Ikarashi et al . In Figure A, H‐300 × 150 × 6 × 9 (No.…”

“…In Figure 12(A-2) and (B-2), the out-of-plane deformation is constrained at 0.25L from the fixed end. With regard to the position of the out-ofplane deformation, it can be assumed to be 0.3L to 0.4L based on the optimum bracing position, which switches the first buckling mode to the secondary mode, derived by Kimura and Yoshino 19 ; previous cyclic loading tests on I-shaped beams collapsed with the local buckling in the tests conducted by Ikarashi et al 20 ; and the wavelength of local buckling along the beam axis obtained from the strain distribution on the flange reported by Kimura 11 under no axial force. In addition, under compressive axial force, the preliminary analyses confirm that the wavelength of the local buckling becomes shorter, and the out-of-plane deformation due to the lateral-torsional buckling tends to be larger than that under no axial force.…”

The plastic deformation capacity of the structural system for thin‐web steel beam reinforced with stiffener plates

“…In previous study of H-beams with large web width-tothickness ratios in which the beam ends are stiffened by stiffeners, the plastic deformation capacity of steel beams has been confirmed to be improved by stiffeners [1]. Various types of stiffening methods for beam ends have been proposed [2], and the improvement in plastic deformation capacity of steel beams due to stiffeners has been confirmed.…”