Lateral stability of deep-thin flanged i-shaped beams with vertical stiffeners

Abstract EN

In this work, the effect of vertical stiffeners on the lateral stability of deep thin flanged I-shaped beams was investigated.

A mathematical model was established to compute the magnification in the warping moment capacity when edge and intermediate vertical stiffeners were utilized.

Hence the magnification in the beam moment capacity was determined as per the ratio of the stiffeners torsional stiffness to the compression flange flexural stiffness.

A proposed design procedure for vertically stiffened deep-thin flanged I-beams was established by substituting the derived warping moment magnification factor in the nominal moment expression for buckling limit states of beams adopted in the ECP-LRFD.

The proposed design procedure was verified by the finite element method using the general purpose finite element program, ANSYS.

A wide variety of beams geometric dimensions was included in the analysis to cover both inelastic and elastic warping limit states.

Four types of vertical stiffeners were studied including plate, opened angle, closed angle and box-shaped stiffeners.

Material and geometric imperfections were incorporated in the finite element analysis.

The effect of using vertical stiffeners on moment magnification of beams was assessed to encourage designers to account for their effect in the design of deep-thin flanged beams and to select the suitable stiffeners configuration.