高强钢S460高温力学性能研究与抗火设计建议

针对钢结构抗火设计中高强度结构钢材料力学性能参数的取值进行研究.为研究最常用的高强度结构钢S460N在高温下的力学性能,对其在稳态和瞬态不同火灾情况下进行材性试验,得到不同温度下S460N的弹性模量、屈服强度和极限强度的折减系数,并与现有文献和现行主要钢结构设计规范进行对比分析.通过与现有文献中欧标钢S460N和S460M、国产钢Q460以及普通钢的研究结果的比较,发现高温下结构钢的力学性能退化取决于钢材种类及其加工工艺.因此,各国现行的钢结构设计规范基于普通钢研究成果得出的设计建议不适用于高强度结构钢.此外,给出可用于指导设计的高强度结构钢S460N在高温下力学性能退化的拟合公式,并对其进行校验.

Study on Mechanical Properties of High Strength Steel S460 at Elevated Temperatures and Fire-resistance Design Recommendations

This paper investigates the parameter evaluation of mechanical behavior of high strength structural steels in fire-resistance design. In order to reveal the elevated-temperature mechanical properties of high strength steel S460N, tensile tests were conducted under both fire conditions of steady state and transient state. The elevated-temperature reduction factors of elastic modulus, yield and ultimate strengths of S460N were obtained and compared to those in the current design standards and available literature. According to the comparison between the research results on S460N, the available research results in literature on S460N, S460M, Q460 and various mild steels, it is found that the deterioration of mechanical properties of structural steels at elevated temperatures is dependent on steel grades and manufacturing method. Therefore, the recommendations in current design standards are not applicable to high strength structural steels. Moreover, unique predictive equations for the deterioration of S460 mechanical properties at elevated temperatures were proposed and validated against the available literatures.