Evaluation of Seismic Damage Indices for Reinforced Concrete Structures

Keywords: Local Damage Indices, Damage Levels, Reinforced Concrete Frames, Seismic Response, Computer Programs, SARCF-II, Maximum Softening Index, Global Damage Indices, Damage Index, Final Softening Index, and Structural Response.

Abstract: This report presents some new information about the correlation between various local and global damage indices and the damage level. This information is obtained by analyzing the results of numerical simulations of the seismic response of three code-designed reinforced concrete frames subjected to a set of artificially generated and recorded earthquakes. The results were computed by using an improved version of the computer code SARCF-II. This new version is tested by comparing computed results to experimental ones obtained from a reinforced concrete model tested at the University of Illinois at Urbana-Champaign. The maximum softening as a global damage index is compared to weighted averages of local damage indices and to traditional measures of damage such as the maximum interstory drift, the permanent interstory drift and the maximum ductility ratio for beams and columns. This maximum softening index is also compared to the final softening one. The global softening indices are helpful for identifying structures that need careful inspection after an earthquake, and are applicable to reinforced concrete structures with or without shear walls.