Material characterisation tests of ultra‐high‐strength steels S960QL and S1100M under natural fire conditions

Fire hazards represent one of the most important threats to the built environment with serious economic consequences for society and most dangerous threats to life. Fire engineering is the key discipline to improve fire safety in the building environment in a cost‐effective manner. Comprehensive knowledge of the material behavior is the basis for a thorough understanding and a realistic modeling of the structural fire behavior of steel structures. For state‐of‐the‐art buildings with increasing requirements, the utilization of high‐strength steels is favorable, as they can contribute to resource and energy efficiency due to their good strength‐to‐weight ratio. Modern production processes enable the production of structural steels with very high nominal yield strengths. For those ultra‐high‐strength steels there are currently no experimental results available regarding the material behavior in case of fire and the post fire residual strengths. The paper provides experimental data of the first test program regarding the constitutive material behavior of ultra‐high‐strength steels of grades S960QL and S1100M in the case of fire, taking into account the entire fire progress including the heating and cooling phases and the post fire range.