The Rognosa tower – San Gimignano (SI)
The San Gimignano Rognosa tower, built during the 13th century, is one of the historic centre’s most ancient and best preserved monuments. With the aim of assessing its dynamic behaviour and seismic vulnerability, the tower has been analysed using the NOSA-ITACA code. The tower has been discretised into 6477 shell elements, so as to obtain a model that is more manageable than a full three-dimensional model made up of solid elements, yet at the same time able to capture the most important features of the tower’s dynamic behaviour. The structure was subjected first to its own weight and then to a seismic acceleration applied at its base, using the data from a natural accelerogram recorded during the 1997 Nocera Umbra earthquake. Although the maximum values of the stress and crushing strain are reached at the base of the tower, the nonlinear dynamic analysis highlights additional damage also in the structure’s uppermost parts, where the highest values of tangential fracture strain are attained, near the openings and in correspondence to the bell chamber.