Involvements of stress triaxiality in the brittle fracture during earthquakes in steel bridge bents

Stress triaxiality is proposed as one of the key parameters to discuss the cause of brittle fracture during earthquakes in steel structures. This study analytically investigated the features of stress triaxiality in steel bridge bent subjected to earthquakes. The target structure is a steel bridge bent actually fractured during the South Hyogo prefecture Earthquake. From the investigations, it was confirmed that high stress triaxiality was generated at a point supposed as fracture origin. There is a possibility that the triaxiality was involved in the fracture strongly through the increase of maximum principal stress. Moreover, from the analyses accounting for several kinds of large earthquake waveforms, it was indicated that threre is possibility that the distribution of triaxiality around the fracture origin was not affected by significantly by each cycle and each waveform.