A Strain-Driven Moment-Curvature Analysis of Composite Cross-Sections Exposed to Fire

This paper presents a novel strain-driven incremental-iterative procedure for moment-curvature analysis of composite steel concrete cross-sections of arbitrary shape exposed to fire.The equilibrium equations are expressed in terms of prescribed axial force and bending moment ratio, while the inelastic behaviour and the solution are controlled at the fibre level, enhancing the global convergence properties of the entire process.The distinctive features of the strain-driven approach outlined here include its ability to accurately capture all critical points on the complete moment-curvature diagrams and eliminate the need for specialized load-path numerical strategies to address singular points associated with ultimate strength capacity.The validation process involves comparisons with other numerical results and experimental data from international literature, extending also the benchmark results used for strength capacity assessment and moment-curvature diagrams of composite cross-sections exposed to high temperatures.