Experimental and numerical investigations into S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures

• Published in: Thin-walled structures 2023-02, Vol.183, p.110349, Article 110349
• Main Authors: Su, Andi, Jiang, Ke, Wang, Yuyin, Zhao, Ou
• Format: Article
• Language: English
• Subjects: Heating; Local buckling; Numerical modelling; Post-fire cross-section compression resistance; S960 ultra-high strength steel; Slenderness limits; Soaking and cooling; Welded I-section stub columns
• ISSN: 0263-8231
• DOI: 10.1016/j.tws.2022.110349

This paper reports experimental and numerical investigations into S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures. A testing programme was firstly conducted and included heating, soaking and cooling of specimens as well as post-fire tensile coupon tests, initial local geometric imperfection measurements and stub column tests. Following the testing programme, a numerical modelling programme was conducted, where finite element models were developed and validated against the test results and then employed to perform parametric studies to generate further numerical data over a wide range of cross-section dimensions. Given that there are currently no available design standards for high strength steel structures after exposure to elevated temperatures, the relevant ambient temperature design rules, as set out in the European code, American specification and Australian standard, were assessed, using post-fire material properties, for their applicability to S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures. The assessment results revealed that the codified slenderness limits for plate elements in compression were generally accurate when used for cross-section classification of S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures up to 700 °C but conservative for higher temperatures beyond 700 °C. Moreover, the codified design rules were shown to provide accurate and consistent post-fire cross-section compression resistance predictions for S960 ultra-high strength steel welded I-section stub columns after exposure to elevated temperatures up to 700 °C but resulted in conservative predictions for higher temperatures beyond 700 °C. •The post-fire behaviour of S960 ultra-high strength steel welded I-section stub columns is studied.•14 stub column tests are conducted.•FE models are developed and validated against the test results and then used to perform parametric studies.•The applicability of the codified slenderness limits is assessed.•The applicability of the design rules for cross-section compression resistances is assessed.