Behaviour of stainless steel reinforced concrete beams in fire

Abstract

Stainless steel possesses excellent mechanical and physical properties, has outstanding corrosion resistance, and is extremely ductile. It finds extensive use in the construction industry and has increasingly been employed in reinforced concrete structures in recent years as there is greater focus on longevity and life cycle costing. However, there has been limited to no research on the fire resistance of stainless steel reinforced concrete structures. In this study, a finite element model of a stainless steel reinforced concrete (SSRC) beam is developed and verified to simulate the fire resistance of the SSRC beams. The model is validated through comparison with available test data before it is employed to undertake a comparative study to evaluate the fire performance of carbon-reinforced and stainless steel-reinforced concrete beams. Various factors, such as load ratio, reinforcement ratio, and concrete strength, are analysed for their impact on the fire resistance of these beams. The ductile failure observed in stainless steel-reinforced concrete (SSRC) beams during fire incidents suggests their potential as replacements for carbon steel-reinforced concrete (CSRC) beams, particularly in fire-prone areas where structural integrity is paramount. SSRC beams can achieve comparable fire resistance to CSRC beams with lower reinforcement ratios, thereby reducing reinforcement requirements potentially. It is shown that stainless steel reinforced concrete beams deform more under flexure than equivalent carbon steel beams largely owing to their greater survival time and resistance to greater temperatures, significantly affecting the fire resistance. A proposed critical temperature limit of 765 °C for SS reinforcing rebar under fire exposure is recommended as a design guideline.