EESD seminar

Title: Historical masonry churches and towers: Seismic vulnerability evaluation and reduction

Abstract:

Historical masonry structures like churches and towers (medieval defense towers, bell towers and city gates) are conceived to withstand only gravity loads and therefore they are always vulnerable to seismic actions. For developed countries, both the knowledge of their vulnerability and the implementation of strengthening for a seismic upgrading are paramount. Consistently with the need of a sound protection of such kind of structures against seismic events, specific Guidelines for the built heritage have been conceived in Italy (where 5% of world UNESCO sites is present), which provide useful hints to practitioners for an assessment, but still leave important open issues. In the seminary, a fast review of existing numerical approaches used for churches and towers is discussed. In particular, for masonry churches, a guidebook for a reliable vulnerability evaluation is proposed. It relies into a broad blend of different approaches ranging from the easiest ones –usually available to practitioners- to the most sophisticated, as for instance3 Non-Linear Dynamic Analyses with damaging materials. A simplified kinematic limit analysis with coarse mesh adaptation is finally reviewed, which is sufficiently simple for common use but at the same time allows for a realistic prediction of the most vulnerable macro-elements and the collapse acceleration. For towers, a simple but reliable limit analysis approach relying into a vulnerability evaluation by means of five probable (observed) failure mechanisms is proposed to overcome the limitations of a too simplistic cantilever beam approximation and to avoid demanding non-linear full 3D FE computations. On the base of the active mechanisms found, the most suitable strengthening interventions for an effective vulnerability reduction are discussed.

About the speaker:

Gabriele Milani is associate professor of structural mechanics at Politecnico di Milano, Italy. So far, he has authored more than 170 papers on international journals and edited a book. He is the second author in Scopus under the keyword “masonry”. He has been awarded an ICE Telford Premium, a most cited author by Computers & Structures and a Bathe award. He is EIC of a journal on masonry (International Journal of Masonry Research and Innovation) and co-editor of a generalist journal (Open Civil Engineering Journal). He is in the editorial board of Computers & Structures and Structural Engineering and Mechanics.