Assessment of cast steel anchorage fracture toughness of a cable-stayed bridge by small punch test

The assessment of the residual lifetime of in-service structural components requires knowledge of fracture toughness values; however, conventional test methods for measuring fracture toughness demand the removal of large material samples from components, which generally is impractical. Recently, the Small Punch Test (SPT) (which utilizes nonstandard miniature specimens) has been used as a practical and convenient alternative for evaluating fracture toughness characteristics of the material of components in service. The purpose of this research was to find a correlation between the SPT equivalent fracture strain e qf and the fracture toughness J IC of low-alloy cast steels coming from anchorages of a cable-stayed bridge, which is located in the Gulf of Mexico. Fracture toughness was calculated from K IC experimental data from previous work and equivalent fracture strain e qf was obtained by SPT using specimens 10×10 mm 2 squares of 0.5 mm thickness. From e qf and J IC results and corresponding low-alloy steel experimental data from literature, a linear correlation was proposed to estimate fracture toughness from SPT equivalent fracture strain for cast steels belonging to this study case.