Time-dependent reliability assessment and durability analysis of industrial and recycled steel fiber reinforced concrete beams

This paper investigates the performance evaluation of high-strength steel fibre reinforced concrete beams (HSFRC) under various corrosion environments. A durability analysis of reinforced concrete structures in coastal areas is conducted, focusing specifically on the time-dependent reliability of shear resistance in beams reinforced with industrial steel fibres (ISF) and recyclable steel fibres (RSF). A novel shear model accounting for corrosion effects is proposed to assess the over-time reliability of beams under different environmental conditions. The shear capacity of ISF and RSF reinforced concrete beams is examined and predicted using extensive experimental data and theoretical foundations. Compared to RSF-reinforced beams, ISF-reinforced beams exhibit superior mechanical performance, particularly in residual shear strength and long-term durability under corrosive environments. Nevertheless, RSF remains a viable alternative due to its sustainability advantages, providing an environmentally friendly solution while maintaining adequate structural performance. The study addresses chloride-induced corrosion by introducing a calculation method for corrosion initiation time and considers chloride ion transport mechanisms impacting structural lifespan. Additionally, probability information and reliability indices over time are computed by employing the improved First Order Reliability Method (FORM-iHLRF) for the performance functions of HSFCRC beams. A comprehensive evaluation is also conducted on key research parameters influencing concrete corrosion within the established calculation framework. Results indicate that increasing concrete protective layer thickness and reinforcement ratio effectively enhances structural reliability. Although the addition of ISF does not enhance the overall reliability index of the beams, it notably prolongs the structure’s service life. Among environmental factors, temperature emerges as the most crucial factor influencing the corrosion process of structures. This study offers theoretical and methodological support for designing and maintaining the HSFRC structures in coastal areas, filling a research gap in related fields. • Proposed an innovative corrosion mechanism model to evaluate corrosion in HSFRC beams. • Applied FORM-iHLRF for analysing the long-term reliability of concrete structures. • Developed a shear model to assess the performance of ISFRC and RSFRC beams, considering the impact of corrosion. • Conducted sensitivity analysis on key parameters affecting structural durability. • Optimized concrete structural design using experimental data and SFRC beams to assess time-dependent reliability.