Study on safety assessment method considering the deterministic characteristics of existing masonry structures

This paper presents a novel method to safety assessment, considering the deterministic characteristics of existing structures. Initially, the concept of disposable resistance is introduced, stemming from the deterministic attributes of the existing structure, leading to the formulation of the limit state expression. Subsequently, a rational value for the ratio of the permanent action effect to resistance is derived, serving as the foundation for optimizing the partial factors within the limit state expression. The rating principles for the safety assessment of existing structural members are established. Finally, a systematic study of safety assessment methods for existing masonry structures is conducted. The findings indicate that in evaluating the safety of existing masonry structures: (1) the resistance partial factor (rR) is set at 2.1; (2) the permanent action partial factor (rG) is assigned a value of 1.0; (3) for variable action factors (rQ), values of 1.3, 1.4, and 1.5 are applied, respectively, for subsequent working years of 30a, 40a, and 50a. The assessment method proposed in this paper is more in line with the reality of existing structures and can effectively avoid over-strengthening of structures.