Large Deflection and Stability OF RIGID FRAMES

Abstract

A method for analyzing in‐plane deflections of elastic framed structures by numerical integration of the exact differential equations governing the finite bending and axial deformations of beams has been developed and applied to nonrectangular rigid frames. In principle, the method leads to exact results. Load‐deflection curves, up to buckling, were calculated for gabled bents with and without overhangs, under symmetric and asymmetric distributed loads and under combinations of independently prescribed distributed and concentrated loads. Asymmetric as well as symmetric gabled bents and a two‐story, two‐bay frame were analyzed. Load‐deflection curves, interaction diagrams, and curves showing the results of parametric studies are presented. Symmetric gabled bents under symmetric loads were found to buckle in either a symmetric snap‐through mode or by sidesway according to rise‐to‐span ratio and column height‐to‐span ratio. In virtually all cases considered, it was concluded that the members of a frame would have to be unrealistically thin for the frame to buckle elastically.