Flange Bending in Single Curvature

Local bending of beam and column flanges is a common design consideration in steel structures. In most cases, the flange bends in double curvature due to the restraining effect of the connecting element. When a restraining force is not present, the flange will deform in single curvature. Common cases of single-curvature bending occur at the bottom flange of monorail beams and at hanger rod connections. In this paper, the equivalent width method was explored in an effort to determine design procedures for elastic and plastic strength of flanges in single-curvature bending.This paper compares the available procedures for designing flanges bent in single curvature. New finite element models and yield line analyses are used to verify, expand and improve the existing design methods. Design recommendations are made for both elastic and ultimate strength approaches. Recommendations are also made for interaction of the local bending strength with longitudinal stresses in the flange. The effects of closely spaced loads and loads acting near the ends of members are also addressed.