Finite Element Model Calibration of a Historic Masonry Church Using Ambient Vibration Testing and RMSE-Based Model Updating

This study addresses the need for reliable calibration of finite element (FE) models of historical masonry structures, whose dynamic behavior is often poorly represented without experimental validation. The objective is to calibrate a numerical model of the San Pedro Apóstol Church (Uchumayo, Peru) using ambient vibration data. An experimental campaign was conducted using a TROMINO® seismograph, and modal parameters were identified through signal processing techniques. A parametric grid-based calibration approach was implemented to systematically adjust the mechanical properties and reduce discrepancies between numerical and experimental responses. The results show that calibration required a significant reduction of the elastic modulus depending on the structural component, ranging from 60%–80% in concrete rings, 60%–80% in the nave vault, 60%–70% in masonry walls, and 20% in the tower. The comparison between numerical and experimental modal periods indicates a satisfactory agreement for the first modes, while higher modes exhibit larger discrepancies, consistent with the expected sensitivity to local effects and modeling assumptions. The study demonstrates that systematic model updating based on ambient vibration testing provides a practical and reliable approach for representing the dynamic behavior of heritage structures and supports their seismic assessment and conservation.