Meta-Model Assisted Continuous Vibration-Based Damage Identification of a Historical Rammed Earth Tower in the Alhambra Complex
Enrique García‐Macías, Israel Alejandro Hernández-González, Esther Puertas, Rafael Gallego, Rafael Castro‐Triguero, Filippo Ubertini
Abstract
This work presents the development of a model-based online damage identification \nsystem for a 13th century rammed earth (RE) tower in the Alhambra, the Muhammad Tower. The system is fed with continuous data from an ambient vibration-based \nmonitoring system and a meteorological station. Ambient vibrations are continuously processed through Operational Modal Analysis (OMA), and environmental \neffects are minimised via statistical pattern recognition. The normalized modal signatures are used to update the stiffness properties of certain parts of the tower \nthrough inverse model calibration. To do so, a high-fidelity three-dimensional finite \nelement model (FEM) of the tower is developed. Since its computational burden \nprecludes conducting online calibration, the FEM is bypassed by a light Kriging \nsurrogate model (SM). In this light, the developed SM-assisted system identification constitutes a long-term Structural Health Monitoring (SHM) system outputting \nquasi-real-time series of modal properties and local stiffness parameters, so providing \nfull damage assessment (detection, localization and quantification). The presented \nresults refer to a time period of three months since January until March 2022. \nNumerical results and discussion are reported concerning the characterization and \nremoval of environmental effects, and synthetic damage scenarios through non-linear \nsimulations are used to validate the developed damage identification system