Second-Order elastic analysis of frames using single imperfect element per member

In practical stability design and analysis of steel members and structures, one must allow for member imperfection. Various national design codes impose different values of initial imperfection for member-strength determination, such as 0.001 of the member length in the 1986 Load and Resistance Factor Design Specification for Structural Steel Buildings. This paper presents a new method of including the effects of initial imperfection in the element stiffness without needing to adopt a curved-element formulation, which is deficient for members under high axial load, or to divide a member into two or more straight elements in order to simulate member imperfection. A very considerable savings and convenience in data-manipulation effort and computer time can be achieved when using the proposed element.