Crack Pattern Quantification for Advanced Visual Inspection of Concrete Structures

Abstract

Visual inspection (VI) is the most common non-destructive evaluation (NDE) technique for concrete structures. In many post-event assessments, cracks information including width and pattern are recorded and decision is made based on engineer experience and knowledge. However, residual closed cracks are sometimes the only available data for VI due to adjacent elastic members, earthquake displacement spectrum, or re-centering systems. Therefore, the measurements may lead to erroneous decisions. To overcome this problem, this paper proposes a novel damage index based upon Fractal Dimension (FD) analysis of residual cracks as a complementary method for VI. FD can temporally monitor a quantified crack pattern and facilitate interpretation of damage grade (DG). This algorithm was validated through experimental studies on a large scale reinforced concrete shear wall (RCSW). The results demonstrated improvement of visual inspection considering the new FD-based damage index.