Description
Historical masonry constructions were typically designed and built by considering exclusively the gravity loads. Unfortunately, their structural weaknesses are mostly related to two different factors: the horizontal loads (earthquake) and creep effects. The first is currently object of intense research activity, which results in updated design codes and guidelines at both national and international level. The latter is a rarer event which affect mainly those structure carrying huge dead loads such as towers. In order to assess the structural vulnerability of high masonry buildings, commonly these two factors are considered non mutually in the analysis. Since historical towers are attended to be preserved in a long-time period, the seismic vulnerability should be considered by taking into account the creep effects occurred along the decades or centuries of service life. At this scope, a case-study is presented herein referring to an ancient masonry tank tower located in the south of Italy within a low seismicity region. The tank’s use drastically affected the structures which was severely overloaded and creep effects are not negligible. By means of Finite Element Method (FEM), associated to available masonry creep analytical laws, the structural behavior was simulated at different grades of creep deformation. A preliminary experimental investigation was performed in order to know the materials and the structural details. Then a push-over analysis was conducted by varying the mechanical parameters of the masonry according to the creep law at different ages. The conclusions of the study offer valuable information that include the creep effects with respect to the seismic vulnerability assessment.
