Fracture assessment procedure developed in Japan for steel structures under seismic conditions

The Engineering Standard, WES 2808, has been developed in Japan for assessing the brittle fracture of steel-framed components at the earthquake. This paper describes the key contents of WES 2808 and demonstrates the application to beam-to-column connections. WES 2808 includes two unique ideas: (1) a reference temperature concept for the evaluation of the material fracture toughness under cyclic and dynamic loading, and (2) an equivalent CTOD concept for the correction of CTOD toughness for constraint loss in structural components. A skeleton strain is employed to define the pre-strain prior to fracture during cyclic loading. The revision of WES 2808 has been done in 2017 to expand the range of use and to improve the accuracy of CTOD toughness correction on the basis of ISO 27306-2016. It is shown that fracture strains of beam-to-column subassemblies predicted by WES 2808 are in a good agreement with those measured.