Damage Assessment of Reinforced Concrete Structures Using Fractal Analysis of Residual Crack Patterns

Currently, assessing the performance and safety of reinforced concrete structures relies on routine-based visual inspection (VI). Cracks width measurements are commonly used as a convenient indicator of damage; however other factors, such as distribution and pattern of the cracks should be considered equally important in measuring the extent of damage present in the structure. As a result, condition assessed by VI is subjective in nature and depends on the experience, knowledge, expertise, and judgment of the inspector carrying out the assessment. A new approach based on the fractal analysis of residual crack patterns is proposed in this paper to assess the structural integrity of reinforced concrete elements. A new damage index is presented to quantitatively perform a damage classification. The methodology is validated through experimental studies on two large-scale reinforced concrete shear walls subjected to a displacement controlled reversed cyclic loading. Damage grades are also identified based on width of cracks and proposed damage index (DI). The results demonstrate a more accurate estimation of damage grades using DI. Furthermore, it is demonstrated that the DI can estimate the relative stiffness loss of the specimens with acceptable accuracy.