高强结构钢S690高温力学性能

Mechanical Properties of High Strength Steel S690 at Elevated Temperatures

摘要:

在火灾下，材料力学性能的退化是导致钢结构承载力降低的主要因素.对高强结构钢S690进行稳态和瞬态火灾试验研究，并将S690的高温材性试验结果与欧洲、美国、澳大利亚、英国和中国钢结构设计规范进行对比，结果表明，依据各国现行钢结构设计规范进行高强钢S690钢结构的抗火设计是不安全的.另外，对试验得出的高温下高强钢S690的弹性模量、屈服强度和极限强度折减系数进行数值拟合，给出可准确表征S690高温下材料性能退化的预测公式，可用于指导含高强钢S690构件的钢结构抗火设计，并为相关规范的修订提供参考依据.

关键词:高强钢; S690; 力学性能; 折减系数; 高温

Abstract:

Under fire conditions, the load bearing capacity of steel structures reduces mainly due to the deterioration of its mechanical properties. In this paper, an experimental investigation was conducted, using both steady state and transient state methods. The comparison of test results with European, American, Australian, British and Chinese design standards of steel structures shows that fireresistance design of steel structures with S690 is unsafe according to the current design standards. Based on the reduction factors of the elastic modulus, and the yield strength and the ultimate strength of S690 obtained from this study, some specified predictive equations were proposed to describe the deterioration of mechanical properties of S690 at elevated temperatures. The predictive equations can be employed for practical fireresistance design of steel structures with members made of S690, providing reference for the revision of current worldwide leading design standards.

Key words:high strength steel; S690; mechanical properties; reduction factor; elevated temperatures