Comparison between codes of practice for designs by LRFD method

In this paper a procedure for the comparison of steel column design by load and resistance factor design (LRFD) method, between the Egyptian code and other codes of practice, is set out. A column design curve for slender sections was established by applying a reduction factor, Q, to the LRFD column design curve. A stability analysis was conducted to study the effect of plate local buckling on flexural column buckling. A finite element model of an axially loaded I-column was developed using shell elements. Material and geometric nonlinearities were incorporated. Geometric imperfections similar to the first buckling mode with amplitude of 1/750 of column length, L, were applied. The analysis was carried out using a general purpose finite element program ANSYS. A wide range of plate width-to-thickness ratios and column slenderness ratios was studied. Column sections were grouped into three: Group 1; sections with slender unstiffened plate elements, Group 2; sections with slender stiffened plate elements, and Group 3; sections composed of slender stiffened and unstiffened elements. The buckling loads for 144 I-column configurations made of steel St.37, St.44 and St.52 were compared to respective values adopted by the AISC-LRFD and Eurocode 3 specifications.