Condition assessment and damage localisation for bridges by use of the Deformation Area Difference Method (DAD-Method)

Already today, a huge number of bridges are in an ailing condition due to their increasing age and due to an increased traffic volume, especially of heavy transport vehicles. To assess their load bearing capacity and subsequently predict their remaining life span, every bridge needs to be analysed by con-dition assessment. The consequences of unreliable condition assessment should not be underestimated, as most bridge constructions constitute cost intensive and indispensable infrastructures. Thus, modern condition assessment methods, easy and obvious in their application, are needed in order to reduce future investigations.
To offer an easy handling alternative to evaluate the condition of bridges, the Deformation Area Dif-ference Method has been developed. Hereby, the accruing deformation of bridges under a static load will be analysed with the help of modern measurement equipment. Therefore, the resulting defor-mation curves like the deflection, the inclination angle and the curvature curves, will be analysed in one diagram together with the results out of initial measurements or theoretically calculated defor-mation curves. The DAD-Method is then applied on the surface difference area between those two curves for the deflection, the inclination and the curvature. It will be demonstrated that a localisation of damage is possible, independent from the degree of damage.
In this study, the applicability of the DAD-Method including the comparison of innovative measure-ment techniques using a laboratory specimen is investigated. For further explanation of the back-ground of the DAD-Method, the results from a FE-calculation are presented.