A study on the application of self-centering capacity based on PT strands and angles that were capable of absorbing strain energy to steel moment resisting frames has been conducted. First, cyclic loading analysis on interior self-centering connections was conducted in order to understand the behavior of self-centering connections based on the different conditions of PT strands. Furthermore, nonlinear dynamic response characteristics of steel self-centering moment resisting frames in which analysis parameters were initial posttensioning force and angle strength has been also studied by comparing that of conventional steel moment resisting frames.

The results of this study are as followings;

1) As initial posttensioning force applying to the PT strands increased, flag shape of hysteretic characteristic of the self-centering connections was more distinctive and strength of these connections increased linearly but with predominant flexural yielding in beams resulted from high initial posttensioning force residual displacement and plastic strain energy increased.
2) The results of cycle loading analysis showed that strength and ductility of the interior self-centering connections improved linearly as the number of PT strands increased from one to four. When the number of PT strands was four the maximum flexural moment was 1.65 times, the maximum drift was 1.66 times and the elastic drift was 3.3 times larger than that when the number of PT strands was one.
3) It is also appropriate that initial posttensiong force applying to one of PT strand needs to be less than or equal to 75% of yield strength of the PT strand so as to maintain for PT strands to be elastic within 4% drift ratio.
4) Nonlinear seismic response analysis on self-centering moment resisting frame according to the decompression moment ratio from 0 to 0.6 was conducted using 3 historical earthquake waves and the response values of the self-centering frames such as story displacement, residual displacement, maximum acceleration and story shear force was the greatest when the Kobe earthquake waves was applied to the self-centering moment resisting frame. Maximum inter-story displacement increased linearly and residual displacement decreased as the decompression moment increased.
5) The maximum drift of self-centering moment resisting frames at first floor was the largest and similar with that of conventional steel moment resisting frames regardless of the initial posttensioning force and the angle strength due to yielding of first floor columns. Therefore, only pt strands is not enough to reduce the maximum drift in the first floor but the maximum drift in the third and fourth floor was reduced up to 50% than that of conventional steel moment resisting frame. In addition, maximum inter-story displacement in the middle story of the self-centering moment resisting frames and residual displacement was controlled more effectively than that of conventional steel moment resisiting frame.
6) The seismic performance on the self-centering moment resisting frame according to the decompression ratio from 0 to 0.6 and angle strength ratio from 0.2 to 0.8 was analyzed by using response reduction ratio of the self-centering moment resisting frame against that of conventional steel moment resiting frame. Seismic performance level was also used to evaluate seismic performance depending on the analysis parameters.

Since analysis on the limited frames has been carried out, it is considered that further study is needed by expanding the number of stories and spans and so on.