Structural safety is a concept defined in various ways, usually in an imprecise and qualitative manner. The article refers to the more important concepts and methods of structural safety assessment and presents an original proposal for a multi-faced assessment of this feature. Suggested procedure allows to take into account most of the key properties determining the safety of structures, including reliability, risk, resistance and robustness, random and non-random uncertainty of state variables and assessment criteria, potential consequences of failure, and makes possible the visualization of the results. Using the concept of fuzzy numbers, fuzzy statistics and the approximate reasoning scheme it enable to take into account subjective and qualitative information about the state variables, safety criteria, computational method, the professional knowledge and intuition of the designer. The application of the proposed procedure is illustrated on the example of the safety assessment of a reinforced concrete beam designed for flexure. The proposed procedure may be useful at the stage of conceptual design of building structures, as well as for assessing the safety of existing structures.

The knowledge of impacts and the load-bearing capacity of unstrengthened/strengthened structures is a crucial source of information about the safety of masonry buildings near deep excavations, especially in dense urban areas. Incorrect calculations made for such designs can seriously affect not only an analyzed object, but also the adjacent buildings. The safety of masonry buildings can be determined by many factors that are closely related to the hazards presented during the performance of deep excavations. These factors are at first identified and then prioritized. The AHP process in the multi-criteria analysis was used to support the decision-making process related to the verification of factors affecting the safety assessment of masonry buildings in the area of deep excavations. The proper design of building structures, including the verification of the structure strengthening near deep excavations, was found to be the most significant factor determining the safety of such buildings. The methodology for proceeding with the verification of ultimate (ULS) and serviceability (SLS) limit states in accordance with the literature data, current regulations, such as Eurocode 6 and other design standards, and know-how of the authors, described in this paper was the next stage of the discussed analysis.