Methods used to determine the safety factor in terms of the nature of the equivalent stresses distribution and other factors affecting the strength (service life) of structures have been shown for elastic structures that have a static loading. The study establishes relationship between safety factor and service life of construction. Equally stressed structures have smaller safety factor (service life) rather than structures with stress concentrators under otherwise equal conditions.

Key words: safety factor, failure probability function, generalized equivalent stress, influence function, service life of structures.