Mikayel MEKUMYAN - Earthquake Engineering Center, National Survey for Seismic protection, Davidashen - IV Massiv, Yerevan, ۳۷۵۰۵۴, Armenia
GRIGOR VARTANIAN - Farthquake Engineering Center, National Survey for Seismic protection, Davidashen - IV Massiv, Yerevan, ۳۷۵۰۵۴, Armenia

Results of experimental studies for increasing seismic resistance of frame structure strengthened by steel jacket under horizontal reversal loading are given. Investigation was carried out on a ۲-story frame model, scaled ۱/۵, before and after strengthening. It was shown that steel jacket brings to increase in initial stiffness, as well as in bearing capacity of the structure being strengthened, in more than ۴ times. Various hysteresis models were used to describe the real behavior of specimens. Based on the known hysteresis models a modified model was suggested for analysis of structure. However, further improvement of the proposed modification should be carried out. Conclusion was made that seismic resistance of the existing frame buildings, even of those significantly damaged, can be reliably increased by their strengthening using steel jackets