• OpenSees
• dissipatore
• pushover
• dinamica
• sismica
• silos

The aim of this thesis is to evaluate the seismic vulnerability of a silo structure belonging to the ILVA steel industrial plant in Taranto (Italy) and to study an eventual operation of seismic retrofit. The case study is composed of two identical Silos and, considering the low stiffness of the connecting elements, only one has been studied in this thesis. The Silos is used for storing hydrated lime, that is produced in particular furnaces and then is distributed and utilized for two main purposes: (1) to remove the phosphor from “pig iron” in blast furnaces, and (2) to remove the sulphur from liquid steel in a steel plant.
Firstly, an analysis of the available information on the silo is made, such as technical drawings.
Secondly, the seismic response of the structure is studied through non-linear static analysis (pushover -N2 method-) with using the OpenSees software.
At the end, a seismic improvement is studied by using Torsional Bracing System of dissipator and the final result is compared with the initial structure.
The results highlight an increase of the general resistance of the system and, also, an improvement for the maintenance of the bracing system. In fact, in case of seismic event, the steel cylinder of the Torsional Bracing System is the only one element that is damaged, while, on the other hand, in a structure without a retrofit system, it is necessary to replace the total bracing system, resulting in a significantly more expensive and time consuming intervention.