Acoustic emission to assess and monitor the integrity of bridges

Increased axle loads and traffic density necessitate strengthening and widening of traditional masonry arch bridges. The question remains as to how to evaluate the condition of a bridge and assess the effect of modern traffic on its serviceability? The focus of this paper has been the evaluation of the potential for the acoustic emission technique to provide cost effective in-situ long term monitoring of bridge condition. The work was performed on a bridge chosen to be representative of both masonry and reinforced concrete construction methods. The results demonstrate that acoustic emission technique can be applied to condition assessment of bridges. These results confirm that strong acoustic emission signals are obtained from reinforced concrete structures and demonstrate that acoustic emissions can be detected in masonry structures but at lower energy levels. The experimental programme has shown that AE is useful in detecting crack growth and determining the position of the crack tips at a much earlier stage in their development, before they are noticed during visual inspection