A SI-based method for determining the interfacial damage condition of a steel-concrete composite girder

Steel-concrete composite (SCC) girder bridges are at risk of damage due to fatigue loads, adverse environmental conditions, and improper concrete pouring processes. Such damage frequently occurs at the interface of the two materials, with shear stud failures or adjacent concrete cracking being the most common issues. This damage is often concealed, and current non-destructive testing techniques are either poorly suited for assessing interfacial damage in SCC girders, prohibitively expensive, or inadequate for identifying multiple types of damage. The present study utilizes structural intensity (SI) to detect interfacial damage by analyzing the accumulation of vibrational energy flows near the damaged regions. Initially, a scaled model of an SCC box girder is constructed with a 1:4 scale ratio. The SI vector field of the concrete deck was measured using the two-transducer method. Then, the vibrational energy of the entire SCC box girder is visualized through finite element software in conjunction with a post-processing code developed by the authors. The transmission of vibrational energy is then examined from a wave perspective. Finally, the effects of stud damage and concrete deck cracking on vibrational energy flow are analyzed. A preliminary SI-based damage retrieval approach is proposed. This study provides a novel perspective for damage assessment and contributes to advancing research on identifying and evaluating interfacial damage in SCC girder bridges. • An SI-based approach is proposed for interfacial damage identification and evaluation. • Through analyzing the accumulation of vibrational energy flows near the damaged regions. • A scaled SCC box girder is constructed, measured, and calculated via FE-SI analysis. • The effects of stud damage and concrete deck crack are explored. • An indicator relative accumulation ratio of SI is defined and discussed.