Experimental study on post-fire mechanical properties of high strength Q460 steel

• Published in: Journal of constructional steel research Vol. 114; pp. 100 - 109
• Main Authors: Wang, Weiyong, Liu, Tianzi, Liu, Jiepeng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2015
• Subjects: Cooling; Exposure; Fires; High strength Q460 steel; High strength steels; Mathematical analysis; Mechanical properties; Post-fire mechanical properties; Proposed equations; Structural steels; Ultimate tensile strength; Post-fire mechanical properties; Proposed equations; High strength Q460 steel
• ISSN: 0143-974X; 1873-5983
• DOI: 10.1016/j.jcsr.2015.07.019

In order to evaluate the residual strength of high strength Q460 steel structures after fire, an experimental study was undertaken to investigate the post-fire mechanical properties of high strength Q460 steel. Tensile coupons taken from high strength Q460 steel sheets were exposed to different temperatures up to 900°C, and were then allowed to cool down to ambient temperature before they were tested to failure. Two cooling methods were considered, namely; natural air cooling and cooling by water. Tensile coupon tests were conducted to obtain their post-fire stress–strain curves and associated mechanical properties (yield strength, elastic modulus, ultimate strength and elongation). It was found that the post-fire mechanical properties of high strength Q460 steel are significantly reduced below the original ambient temperature mechanical properties if they had been exposed to temperatures exceeding 600°C. Hence a new set of equations is proposed to predict the post-fire mechanical properties of high strength Q460 steel. Such post-fire mechanical property assessments allows structural and fire engineers to make an accurate prediction of the safety of fire exposed high strength Q460 steel buildings. •Tensile tests for high strength Q460 steel were undertaken after cooling down from temperatures up to 900°C.•Post-fire mechanical properties of high strength Q460 steel were reported.•Predictive equations were given for evaluating performance of high strength Q460 steel after fire exposure.•Reference for safe evaluating and reuse of members made of high strength Q460 steel after fire was provided.