Abstract
Understanding the behavior of historic structures that have undergone structural changes, restorations, and damage over time is still a significant challenge for structural engineers, particularly in those countries subject to high seismic risk, such as Italy. The study of built heritage for its prevention and conservation is an active research topic, due to the numerous uncertainties present in historic structures. Finite element modelling has become the most common and accessible method to study the behavior of complex masonry structures, however, the gap between numerical and experimental analysis may lead to erroneous results. Model updating techniques can reduce the discrepancy between the behavior of the numerical models and the testing results. The goal of this work is to illustrate a methodology to integrate the information derived from local, global, and geotechnical investigations into the finite element model of the masonry historical church of San Giovanni in Macerata, considering the Douglas–Reid model updating method. The PRiSMa laboratory of Roma Tre University carried out local investigations such as sonic tomography, video endoscopy and double flat jack tests, along with five ambient vibration tests that were processed through the operational modal analysis to extrapolate the dynamic properties of the building (modal frequency, modal shape vector and modal damping). The combined use of global, local and geotechnical information implemented in the methodology effectively reduced the uncertainties of the model and led the refinement and validation of the most relevant structural parameters.
Highlights
Before the personal computer became widespread, structural analysis was limited to simplified models requiring reasonable computational effort and equivalent graphical methods [1]
The modal parameters derived from the operational modal analysis (OMA), indicated as REi XP with 1 ≤ i ≤ M (M represents the number of extracted modes of vibration), are compared with the related RFi EM values obtained from the analysis of the finite element models (FEM) as described by the relation (4)
The ambient vibration tests and operational modal analysis technique returned fundamental global information on the seismic behavior of the church, while appropriate tests such as sonic tomography, video endoscopy, double flat jacks test, and geotechnical survey assessed the relevant characteristics of the structure and supported the estimation of the unknown parameters
Summary
Before the personal computer became widespread, structural analysis was limited to simplified models requiring reasonable computational effort and equivalent graphical methods [1]. Model updating is a widely used technique in the calibration of finite element models (FEM), in particular considering global properties such as the dynamic behavior of the structure. The Douglas–Reid method [16] is based on the approximation of the natural frequencies with quadratic relationships of the unknown structural parameters; this method has been successfully implemented on civil structures [17] and cultural heritage [18,19,20] To properly apply this technique, it is necessary to develop an accurate numerical model of the structure, consider the proper sensitive parameters of the problem, and set reliable ranges of variation of these parameters. The results from the onsite campaign are implemented in the updating of the numerical model
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
