Architectural evolution. Modifications/Alterations/Restorations along centuries

ABSTRACT:The many towers of San Gimignano make this town unique in the world. Whilst most have disappeared, the surviving towers are even today a very interesting example of ancient simple but high buildings. The construction is surprising, the method is based on very thick stone masonries and extraordinary mortars, with just a few later exceptions where bricks were used. Equally surprising is the inner space, as rooms are sometimes smaller than the wall thickness. For each of the fourteen studied towers detailed surveys were made on internal and external parts. The survey was carried out with laser scanner and traditional instrumentation. For each tower exposed masonries, materials and discontinuities were examined in detail, identifying demolitions and reconstructions which occurred over time. Deformations in vertical and horizontal planes and main cracking phenomena were recorded. Remarkable unpublished data, first of all on dimensional and constructive features of the medieval towers, was obtained.