Fire Performance and Design Recommendations of Very High Strength Steel S960

Abstract:

In order to reveal the high temperature mechanical properties of very high strength steel （VHSS)S960, tensile tests were conducted under both steady state and transient state fire conditions. The elastic modulus, yield strength, ultimate strength, stress-strain curve as well as failure mode of S960 were obtained. The test results were compared with current steel structure codes, such as EC3, ASCE, AISC, AS 4100 and BS 5950, to verify the applicability of standards for high strength steel (HSS). For comparison, the available research results in literature on S460, S690, Q460, Q550, Q690 and Q890 were compared with the test results of S960.Besides, the fitting formula of the mechanical properties of the VHSS S960 under the action of high temperature of fire was put forward, and its accuracy was verified. It is shown that fire-resistance design of steel structures with S960 is unsafe according to the current design standards, and differences of mechanical properties of HSS exist in different kinds of HSS. Moreover, the fitting formula for the deterioration of S960 at high temperatures was validated for practical engineering design.

Key words:very high strength stee（VHSS）;S960;mechanical properties;fire;high temperature;fitting formula