Ultimate Load Behavior of Beams With Initial Imperfections

More exact expressions of the fundamental equations of a member with initial imperfections subjected to the action of bending and torsional moments are derived. Since beam problems involve moderately large in‐plane deformation prior to collapse, only nonlinear terms of in‐plane displacement and in‐plane resulting force are considered in the numerical analysis using the transfer matrix method. In the formulation of stress resultants in a partially yielded section, the equivalent section properties are used. The proposed idea is obtained by a transformed‐section method of analysis of reinforced concrete beams. Finally, the effects of initial deformation, initial lateral deflection, residual stress patterns, strain hardening, and load and support conditions on the ultimate strength and deformation behavior of beams are investigated.