Probabilistic Model Optimization and Safety Assessment Methods for Existing Masonry Structures

The practice of the assessment of the safety of existing masonry structures is related to the safety of people’s lives and property. However, the current assessment method, described in “GB50292-2015 Standard for appraisal of reliability of civil buildings”, fails to fully consider the uncertainty-related characteristics of the structures, which easily leads to unreasonable assessment results. This paper proposes a method of safety assessment for existing masonry structures that considers the updating of resistance and load probability models and different member weights. First, based on the resistance probability model measured in the field, the resistance model in the current code (GB50292-2015) is updated through Bayesian theory. Then, the variable load model is updated for different subsequent working years through the equal-exceeding-probability method. Finally, the safety grade of the existing masonry structure is obtained by the analytic hierarchy process, using the affiliation set as the assessment index. This method of analysis solves the problem relating to the “jump” in the middle of the break-point of the traditional safety grading standard. It also fully considers the uncertainty-related characteristics of the existing structure, and its evaluation results align with the existing structure’s actual situation, which is critical to the assessment of the safety of the existing masonry structure.