This paper presents a simple analytical approach for predicting the overall thermal and structural behavior and inelastic buckling failure of columns subjected to axial load (P) and elevated temperatures from fire loading effects. The approach consists of three parts, (ⅰ) The first part conducts a 2D heat transfer analysis of the cross-section, (ⅱ) The second part conducts a fiber model analysis of the cross-section to predict its fundamental moment-curvature (M-φ-T) behavior, (ⅲ) The third part conducts inelastic column buckling analysis using Newmark's method, which was modified to use the section M-φ-T behavior at elevated temperatures. This analytical approach was implemented and verified for composite concrete filled steel (CFT) columns because they include both steel and concrete materials and are expected to have better fire resistance than steel columns. The approach was verified by comparing analytical results from parts (ⅰ-ⅲ) with experimental results that were developed separately as part of this research, and also using experimental data developed by other researchers. The approach was verified further by comparing the analytical results with those from 3D finite element analysis. The verified approach is recommended for predicting the overall behavior and stability failure of columns under fire loading.
展开▼
