COMINELLI, STEFANIA1; GIURIANI, EZIO2

1) Post-doctoral fellow at the Department of Civil Engineering, Architecture, Land, Environment and Mathematics, University of Brescia, Italy, stefania.cominelli@unibs.it

2) Full Professor of Structural Engineering at the Department of Civil Engineering, Architecture, Land, Environment and Mathematics, University of Brescia, Italy, ezio.giuriani@unibs.it

Massive masonry structures, like historical high towers and large church pillars, can be subjected to critical static loading situations, due to heavy persistent compressive stress, associated with vertical dead load.

In the case of multi-leaf walls, the assessment can be difficult in regards to both, evaluation of the compression strength of masonry, and analysis of the state of stress.

This research is motivated by the problem of the medieval bell-tower of the Church of S. Maria Assunta on Torcello Island in the Venetian Lagoon. The aim is to quantify the redistribution of stress across the wall during the centuries, caused by non-uniformity of creep. Particularly, this study analyses the gradual increase of compression stress in the masonry cladding that could reach critical values.

Due to little experimental information, long-term tests on reproduced ancient lime mortar have been started in order to define the creep behaviour of different mixtures.

Another purpose is to investigate the advantages in terms of stress reduction due to partial and limited rebuilding technique (“scuci-cuci”), frequently used in the past, for the substitution of heavily damaged parts of masonry.

Keywords: Creep, multi-leaf masonry, stress redistribution, tower, “scuci-cuci” technique.