Abstract—This research consists to determine the security margin reliability with probabilistic analysis using the dynamic computed stresses and the RC reinforced concrete strength of a specific bridge structure. The maximum stresses are obtained from a dynamic finite element damage detection analysis in which each value is computed inside a mesh element under severe loadings [1, 5]. The RC strength stochastic characteristics are calculated from experiments and RC composite materials mixture rules. Reliability of computed stresses from a damage detection analysis [1] became an important structural health monitoring process. The main objective of this research work is the probabilistic analysis of the dynamic operating stresses using their calculated stochastic characteristics. This research work allows quantifying the structural warranty period including unpredictable and stochastic phenomena like natural disasters under severe loadings. An important vital structure with known stochastic characteristics is analyzed by quantifying and increasing its lifetime period. The RC strength stochastic characteristics and structural security margin reliability of a specific designed structure are performed.