Flange-induced buckling of plate girders of high strength steel

摘要

Design practice shows that the simple web slenderness limit given in EN 1993-1-5 to prevent flange-induced buckling does not usually govern the web design other than for very slenderness class 4 plate girder webs in steel grades S235 to S355. However, the same formula applied to plate girders designed in S690 or S700 high strength steel (HSS) gives much lower slenderness limits that can govern web design and restrains the possibilities for reducing their thickness to profit from the high steel resistance. This paper reviews the background of the simplified web slenderness limit currently used. The results obtained with this formula are compared with numerical results from full non-linear analysis of steel and steel-concrete composite girders that present different buckling modes of the web. The case of hybrid plate girders adopting HSS only on the flanges and the possible benefits of transverse stiffeners are also investigated.