Thermo–mechanical behavior and validation of a temperature-indexed CDP model for reinforced concrete beams, slabs and columns

Purpose The purpose of this study is to develop and validate a temperature-indexed Concrete Damage Plasticity (CDP) model to analyze the thermo-mechanical behavior of reinforced concrete beams, slabs and columns under fire exposure. By integrating temperature-dependent material properties, this research aims to provide a comprehensive approach for evaluating the degradation of mechanical properties, including damage and strain, at elevated temperatures. The findings contribute to enhancing fire safety design practices, supporting Sustainable Development Goal (SDG) 9 (industry, innovation and infrastructure) and SDG 11 (sustainable cities and communities), by improving structural resilience to fire hazards. Design/methodology/approach This study employs a temperature-indexed CDP model to simulate the thermo-mechanical behavior of reinforced concrete beams, slabs and columns exposed to fire. Numerical simulations are conducted using finite element analysis to assess the degradation of mechanical properties such as stress, strain and damage evolution under varying temperature conditions up to 800°C. Experimental data are used to validate the model's predictions. The approach integrates temperature-dependent material properties, providing a comprehensive framework for understanding the structural response to fire and offering insights for enhancing fire-resistant design in concrete structures. Findings The findings of this study demonstrate that the temperature-indexed CDP model accurately predicts the thermo-mechanical behavior of reinforced concrete beams, slabs and columns under fire exposure. The model effectively captures the degradation of mechanical properties, including damage and plastic strain, at temperatures up to 800°C. Numerical simulations align well with experimental data, showing strong predictive capability, although minor discrepancies are observed at higher temperatures, particularly in deflection and strain. The research underscores the importance of refining temperature-dependent material properties for more accurate simulations of concrete behavior in extreme fire conditions. Originality/value This study provides a novel approach by developing and validating a temperature-indexed CDP model for assessing the thermo-mechanical behavior of reinforced concrete under fire exposure. The model integrates temperature-dependent material properties, offering a comprehensive framework for simulating the degradation of concrete's mechanical properties across various structural elements. The originality lies in the model's ability to accurately predict damage, strain and stress evolution at elevated temperatures, filling a critical gap in structural fire safety design. This research advances fire-resistant infrastructure design, supporting more resilient and sustainable urban structures, contributing to SDG 9 and SDG 11.