Reinforced concrete (RC) box girders are a common structural member for road bridges in modern construction. The hollow cross-section of a box girder is ideal in carrying eccentric loads or torques introduced by skew supports. This study employed acoustic emission (AE) monitoring on multicell RC box girder specimens subjected to laboratory-based torsion loading. Three multicell box girder specimens with different cross-sections were tested. The aim is to acquire AE analysis data indicative for characterizing torsion fracture in the box girders. It was demonstrated through appropriate parametric analysis that the AE technique could be utilized to effectively classify fracture developed in the specimens for describing their mechanical behavior under torsion. AE events localization was presented to illustrate the trend of crack and damage propagation in different stages of fracture. It could be observed that spiral-like patterns of crack were captured through AE damage localization system and damage was quantified successfully in different stages of fracture by using smoothed b-value analysis.
Distal femoral physeal fractures in adolescents are often due to high velocity injuries. We present an unusual case of a non-contact distal femoral physeal fracture that occurred during a football match. A torsional force had been directed at the fracture site occurring at the growth plate causing a transverse fracture rather than a spiral fracture. It is important to be aware that such fractures can occur despite little or no evidence of contact. These type of injuries should also be treated as an emergency to reduce the risk of further complications.