The impact vibration-based fatigue damage assessment of steel and steel fiber reinforced concrete composite girder

Abstract

The steel-concrete composite girder has been usually applied in the civil structures. The current fatigue damage assessment on the composite girder, especially the negative bending region, mainly bases on the crack observation and deflection measurement. It is not stable sometimes, thus the impact vibration-based fatigue damage assessment was considered instead. A 3.3m steel-steel fiber reinforced concrete (SFRC) composite girder was designed and tested. The fatigue load, the impact load, and the static load were applied in the test. It showed that the local fatigue damage reflected by the tensile SFRC cracks may not be easily evaluated through observing the global mechanical change. However, the vibration modal parameters such as the vibration frequency, vibration mode, damping ratio might be useful for this. In particular, the vibration mode variation, which can be expressed by the Modal Assurance Criterion (MAC) value, may reflect the local fatigue damage on the composite girder.