Structural health monitoring and quantitative safety evaluation methods for ancient stone arch bridges

The ancient stone arch bridge holds significant historical, artistic, and scientific value as a vital cultural heritage. To preventively preserve this cultural heritage, a comprehensive approach involving universal structural health monitoring (SHM) and corresponding safety evaluation methods for ancient stone arch bridges is developed. The initial steps involve the design and arrangement of a monitoring system based on damage records and numerical analysis. Subsequently, an evaluation method utilizing the analytic hierarchy process (AHP) is developed with a focus on optimizing weight assignments through an element importance analysis, enabling the calculation of a hierarchical structural safety score from monitoring data to the entire structure to make decisions on structural safety status. An SHM system along with the relevant evaluation framework is field implemented on Lugou bridge as a case study of application. A 15-month monitoring is quantified as a real-time score and reveals that the structure of Lugou Bridge is relatively safe, but structural degradation due to temperature requires special attention. The results show that this framework can be effectively employed as a decision-support tool to inform the real-time structural safety status of various stone arch bridges. The results of this study contribute to the advancement of SHM by providing a decision-making framework for the monitoring and evaluation of ancient stone arch bridges.