Lateral?Torsional Buckling of beams with warping restraints at Supports

In practice, the elastic lateral-torsional buckling of doubly symmetric I-section steel members is analyzed assuming free warping at supports. However, welded stiffeners, bolted end-plate connections or column base plates maintain elastically opposite flange out-of-plane rotations and thus induce substantial restraints. This paper proposes analytical formulations for evaluation critical bending moment beams taking into account restraints Assuming series displacement rotation fields containing one two terms, energy method permits to derive expressions under constant linear distribution moment. A single expression coefficient kw proposed whatever shape diagram. The factor C1 can be conveniently calculated by multiplying coefficients that depend on diagram restraint stiffness, respectively. Finite Elements analyses with supports have been performed considering a beam element model developed LTBeamN shell created in ANSYS. good agreement numerical results obtained finite models.