Post-earthquake damage assessment for RC columns using crack image complexity measures

The seismic peak interstory drift ratio (IDR) of RC columns following an earthquake is measured in this paper through surface crack image analysis. The succolarity, lacunarity and fractal dimensions of the crack patterns for damaged RC columns are considered as the quantitative representatives of the complexity and irregularity of the crack images. An extensive databank of 445 crack maps from cyclic experiments on 110 rectangular reinforced concrete column specimens with double-curvature deformation mode is collected and utilized for the development and validation of the proposed procedure. The research databank covers a broad series of structural and geometric characteristics. Eight predictive closed-form equations are derived aiming at estimating the experienced peak IDR experienced by the RC columns during a seismic event using the accessible structural data from the damaged column. Results reveal that succolarity dimension is a strong vision-based indicator of damage in RC columns. Finally, the methodology is demonstrated through a practical application for a real damaged column in 2017, M 7.3, Kermanshah earthquake.