Differentiating Local and Global Vibration Modes of Heritage Masonry Buildings through the Spatial Correlation of Modal Displacements

ABSTRACT

The effective differentiation between global and local modes plays a fundamental role in the selection and application of the most appropriate seismic analysis procedures. This is particularly relevant in the case of historical heritage structures and ensembles of buildings in old city centres: due to the complexity of the structural scheme, the stratification of interventions, and the irregularity of the structural configuration with the absence of seismic details, several local modes frequently characterize the dynamic response of those structures. Distinguishing local and global modes might be challenging even from the experimental point of view in the presence of few measured degrees of freedom. Nevertheless, an accurate analysis of local modes can support the identification of macro-elements and the selection of the most appropriate analysis procedure. The present paper illustrates an original approach addressing the differentiation between global and local modes through the spatial correlation of modal displacements. The proposed approach can be either automated and integrated into software for structural analysis or applied in the context of an experimental campaign, and its application to simulated case studies is discussed.

KEYWORDS:

• Dynamic response
• global modes
• local modes
• macro-element
• vector correlation

Acknowledgments

The present study has been carried out in the framework of the RELUIS 2019-2021 research program, WP6 Monitoring and Remote sensing, issued by National Department of Civil Protection (DPC), whose financial support is acknowledged. Authors are also grateful for the additional support provided by the PRIN 2017 “SURMOUNT - Innovative Systems for the UpgRade of MasOnry structUres and Non sTructural elements” research project (n. 20173SJJF8).

Disclosure statement

No potential conflict of interest was reported by the authors.