Mitigating damage on heritage structures by continuous conservation using thermal real-time monitoring. Case study of Ziri Wall, city of Granada, Spain

Abstract

Climate change and anthropogenic causes represent a multidisciplinary problem in urban environments, specifically in the destruction of historical elements of enormous value. Although conventional preservation methods are based on comprehensive conservation measures and periodic inspection, these urban elements sometimes lie in a state of neglect due to lack of means to carry out continuous monitoring. The present work develops a replicable and easy-to-apply multi-analytical methodology, which proposes the use of standard monitoring to automatically diagnose the elements of heritage buildings. Similar approaches are becoming popular in the setting of Structural Health Monitoring, and their application in the field of environmental monitoring is one of the valuable outputs of this work. Diagnosis is based on the development of an inverse characterisation model of the thermal response in a known state of conservation through standard monitoring. This model is calibrated using real measurements. The methodology involves characterising energy response to environmental excitations measured against what is deemed to be a baseline state of conservation. Also, the monitoring system and data processing required is defined and explained in detail. Anomalies detected in the comparison of the baseline to subsequent real-time measurements would highlight the need to bring scheduled on-site inspections forward with an affordable cost. This benchmarking using the estimation of baseline and real measurements is the main result of the methodology. Finally, the methodology developed was validated with an exhaustive study conducted on the Ziri Wall at Granada, Spain, in both summer and winter. The findings revealed a good fit between calculated and experimental data, with mean absolute errors of under 1 °C in both seasons. The proposal can be applied in other fields such as preventive maintenance.