Damage-oriented design criteria for earthquake-resistant concrete structures

In this work, new seismic damage indices are developed as explicit seismic design or assessment criteria for reinforced concrete (RC) moment frames. These new explicit damage indices are mechanically well-founded and applicable to individual members as local damage index and to entire structure as global damage index. Both indices vary between 0 non-damaged state and 1 failure state. Recent codes stipulate to design and assess the structure by using performance-based criteria. Here, various performance levels are specified by utilizing either descriptive criteria or displacement limits. However, the damage state of the structure is rather related to an explicit damage index than to its displacement capacity. Considering this fact, a new performance-based design procedure called as damage-based seismic design is proposed by using the new indices. To follow and verify this new design, a reliable finite element program „FRAME“ is developed with the new damage indices within the „MATLAB“ environment for 2D nonlinear analyses. The plausibility of the new damage indices and the reliability of the program are tested on laboratory structures given in literature. It is seen that the new damage index is more plausible than Park and Ang's damage index and the results of the program „FRAME“ correlate better to the experimental results than those of the programs „IDARC2D“ and „RUAUMOKO“. Finally, the proposed damage-based evaluation procedure is performed on a reference frame designed according to the conventional rules of Turkish Earthquake Code (TDY 2007). At the end, the damage-based evaluation is compared with the displacement-based evaluation given in TDY 2007. The damage state of the frame is much better quantified in damage-based evaluation than in displacement-based one.