Experimental assessment of I-shaped steel beams with longitudinal stiffeners under lateral-torsional buckling

Abstract

This study focused on the experimental assessment of the behavior of I-shaped steel beams with longitudinal stiffeners under the action of lateral-torsional buckling. Thirty-three IPE-140 steel beams with and without longitudinal stiffeners were tested under simple-support conditions with a laterally unbraced length ranging from 0.69 to 6.0 m. The stiffeners spacing was 0.42 m, which represented three times the depth of the section. The structural behavior of the beams is discussed in terms of their flexural capacity, the lateral displacement of the compression flange and the failure twist angle. The results showed that the use of longitudinal stiffeners increased the flexural capacity up to 82%, decreased the lateral displacement of the compression flange and the failure twist angle up to 72 and 90% respectively, with respect to the specimens without stiffeners.

Effect of longitudinal stiffeners’ spacing in lateral-torsional buckling

“…In order to validate the experimental results of this research carried out at 1:9 scale, the measured moment vs laterally unbraced length Lb of the specimens without longitudinal stiffeners and with a ratio e/d = 3 were normalized and compared with the experimental results performed on a real scale in the work carried out by (Prado et al, 2018) as shown in Figure 8. Figure 8 shows a good concordance of the values of measured moment of the specimens tested at real scale and 1:9 scale in the inelastic and elastic buckling zone, validating the experimental results of this research, whereas in the plastic buckling zone, the measured moment values are associated to the material strength.…”

“…Finally, Prado et al (2018) experimentally evaluated the use of longitudinal stiffeners with different laterally unbraced lengths Lb. The tests in this study were performed using only a spacing of 420 mm between longitudinal stiffeners, which represented an e/d ratio of 3, defined as the center-to-center spacing of the stiffeners divided by the depth of the section.…”

Strengthening of Steel Beam by Inclined Stiffeners

“…The experimental study of four-point bending of beams IPE 140 equipped with longitudinal stiffeners at beam ends shows that such stiffeners are very effective especially for more slender beams [4].…”