Seismic Damage Index Based on Fractal Dimension of Cracking on Thin Reinforced Concrete Walls

This paper proposes an empirical damage index for rapid estimation of damage level of thin and lightly reinforced concrete walls for housing subjected to seismic demands. The proposed damage index is based on the fractal dimension of the cracking observed during seismic tests of 39 wall specimens constructed with typical characteristics of this type of housing. Variables of the experimental program were the type of concrete, aspect ratio of walls, web steel ratio and type of web shear reinforcement, and the testing method. The effect of these factors on the cracking pattern of walls was assessed by using an advanced statistical analysis method-namely, factorial design. Expected damage index at defined limit states and performance levels are proposed for computing the residual capacity of walls for code-based seismic design and rehabilitation.