Assessment of Seismic Retrofitting Interventions of a Masonry Palace Using Operational Modal Analysis

ABSTRACT

The paper delivers a short report about the modal identification carried out on a historical masonry palace in the city centre of L’Aquila, Palazzo Pica Alfieri, retrofitted after the 2009 earthquake. A concise description of the damage pattern and the retrofitting interventions heads the presentation of the results of the dynamic identification using Operational Modal Analysis. The identified mode shapes and natural frequencies drive a discussion about the detectability and the assessment of the modifications induced by the structural interventions using low-vibration measurements. Differently from more uncomplicated structures, the production of a Finite Element model representative of an existing masonry complex requires considerable efforts: the masonry structure may not behave like a continuum, due to the presence of cracks and unknown structural discontinuities. Still, the results of the dynamic identification bestow valuable information about the structural behaviour from a qualitative viewpoint, even if not backed by a faithful FE model. The paper addresses the aspects possibly related to the dynamic identification of a monumental masonry building, based on the shreds of evidence arisen from the presented case study.

KEYWORDS:

• Dynamic identification
• masonry buildings
• model updating
• operational modal analysis
• seismic retrofitting

Acknowledgments

The authors thank NH M° Fabrizio Pica Alfieri for his support and generosity, acknowledge the contribution of Prof. Antonio Borri and Prof. Dante Galeota, who contributed to the design phase and the execution of the in situ tests, and the contribution of NH Angelo Pica Alfieri, who carried out historical investigations about the palace. The authors further acknowledge the role of the designers: Arch. Giuseppe Chiarizia, Ing. Riccardo Vetturini, Arch. Antonio Posabella, Ing. Giacomo Di Marco, Dr. Gaudenzio Leonardis, Ing. Manuela Villacroce.

Disclosure statement

No potential conflict of interest was reported by the authors.