Damage Detection and Evaluation of Stud Connectors for Composite Girder Bridge Using Acoustic Emission

Abstract

Stud connectors are widely used as shear keys in steel–concrete composite girder bridges, owing to their advantages of easy processing, quick construction, and excellent connection performance. Stud connectors are buried in concrete; therefore, conventional detection methods cannot effectively and reliably detect damage to them. In this study, an acoustic emission (AE)-based methodology was developed to monitor long-term damage to bridge structures and their key components. Damage to stud connectors during the shear failure process was dynamically monitored using the AE technique. AE signals from the entire stud damage process were collected. Subsequently, the characteristic parameters of AE were extracted. According to the process diagram, association graph, and cumulative chart of each characteristic parameter, we first investigated the distributive regularity for the five characteristic AE parameters (energy, ringing count, amplitude, rise time, and duration) of the stud in the elastic, elastic–plastic, plastic, and fracture failure stages. The correlation diagram of amplitude and frequency was also studied. Subsequently, based on the damage factor theory, a damage model of the stud was established by considering the cumulative values of energy and ringing count as the main parameters. The model was further verified using experimental data. More importantly, this proves the feasibility of the model in the quantitative description of the damage process in studs. This study also provides experimental data and a theoretical basis for the detection and evaluation of stud damage in steel–concrete composite girder bridges.