Multilevel structural evaluation and rehabilitation design of an historic masonry fortress

The paper deals with the structural analysis and strengthening design of a masonry fortress, named “Rocca Ariostesca”, located in Castelnuovo Garfagnana, Italy, through the combination of visual/empirical, experimental, and numerical methods. The work was developed within a project aimed at the rehabilitation of the fortress. The project involves the creation of a new museum dedicated to the famous poet Ludovico Ariosto and the Garfagnana region in the sixteenth century. The paper illustrates the evaluation of the conservation state of the building, the analysis of its static and seismic behaviour, and the strengthening design. The first part describes the activities carried out to acquire a suitable knowledge of the structure, which is of fundamental importance to choose the most appropriate analysis strategies and structural strengthening works. The information acquired in the knowledge phase is also important to choose the modelling scale to evaluate the static and dynamic behaviour of the building. The second part of the paper deals with the structural check of the masonry walls and wooden floors for both gravitational and seismic loads. The last part of the paper presents the strengthening design of the building, aimed at increasing the structural capacity to both vertical and seismic loads. The paper highlights how a multi-method approach, through the combination of visual/empirical methods and finite element numerical models, calibrated and validated on experimental data, allow for an efficient and reliable structural evaluation of existing historical masonry buildings and for the design of the structural strengthening. The multi-method approach allows for reducing the uncertainties in the evaluation of the structural safety of the building and to better define its structural rehabilitation and seismic retrofitting. • Knowledge process for a masonry fortress through geometric survey, in-situ tests, and load testing on floors. • Creation of a 3D F.E. model for global static analysis and modal analysis and of a 3D macro-element model for identification of local failure mechanisms. • Seismic capacity of the building mainly controlled by local collapse mechanisms. • Design of non-invasive retrofitting works to solve structural deficiencies respecting the monumental building conservation state.