NONLINEAR ELASTIC BEHAVIOR OF I-BEAMS CURVED IN PLAN

The vertical deflections perpendicular to the plane of a horizontal be am curved in plan are coupled with its twist rotations, and its axial deflections are coupled with its horizontal radial deflections. Becaus e of the first of these couplings, a horizontally curved beam subjecte d to vertical loading has both primary bending and torsion actions. In the nonlinear range, second-order couplings between the vertical and horizontal deflections and the twist rotations are developed, and the nonlinear behavior of the curved beam becomes more complicated. This p aper studies the linear, neutral, and nonlinear equilibrium of elastic horizontally curved I-beams under vertical loading and develops a cur ved finite-element model for their analysis. It is found that when the included angle of a curved beam is small, the primary coupling is als o small and bending is the major action. In this case, the nonlinear b ehavior is similar to the elastic flexural-torsional buckling of a str aight beam. However, if the included angle of the curved beam is not s mall, the primary coupling becomes significant and both torsion and be nding are major actions. In this case, nonlinear behavior develops ver y early and is quite different from the flexural-torsional buckling be havior of a straight beam.