During the Northridge earthquake and the Kobe earthquake unexpected brittle fractures occurred in a number of steel structures. The brittle fracture during earthquakes initiates from a shallower initial crack than that of well-known brittle fractures. This study addresses the shallow crack tip stress field at brittle fracture transition. The crack tip stress field at the instant of brittle fracture is investigated based on the experiments and FE analyses which employed specimens with precrack on notch. As a result, it was confirmed that crack value of maximum principal stress, stress triaxiality and Weibull stress at shallow crack tip is affected by the notch shape and crack depth.
