The Rehabilitation and Strengthening of existing structures represent very significant part of the contemporary construction practice. One of the main problems in the case of Rehabilitation and Strengthening is related to the accepted degree of the interventions, the necessity to reach the safety of the new buildings and the evaluation of the risk, in case of lack of interventions for upgrading the performance of the building. The position of the country in one of the most seismically active

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... as imposes on Bulgarian structural engineers to prove the seismic structural safety for both the newly designed and the existing structures. The existing national technical regulations in Bulgaria are mainly turned on new structures. Only particular articles in the codes give some general recommendations which are not enough for a detailed and correct design. The Eurocode 8-3 is the other possibility for the design of the Rehabilitation and Strengthening but the problems in the application of this standard create serious difficulties in the design practice. The paper makes an overview of the common engineering practice in Bulgaria and presents the full process of seismic Rehabilitation and Strengthening, starting with the procedure of seismic assessment. The most popular strengthening techniques in the Bulgarian practice are presented as well. Тhe analysis is based on several realistic project situations that make possible to identify and present the main difficulties and problems in the engineering practice. Using these specific examples, some key findings and recommendations are made.