Case Study: Seismic Upgrade of a Masonry Bell Tower Using Glass Fiber-Reinforced Polymer Ties

In many cases masonry buildings present structural problems related to development of local mechanisms under seismic actions. The solution to this weakness has to be chosen taking into account several aspects if the construction is ancient and is gifted of monumental significance. In this paper the case of the Bell Tower of Santa Maria del Carmine Napoli, Italy is discussed; the construction has been deeply examined by the writers performing experimental inquires in situ and theoretical analysis with three-dimensional models. While the results obtained in the hypothesis of compact behavior of the structure have pointed out a low risk condition under seismic actions, in contrast the study of local out-of-plane mechanisms, dealt with in detail in this paper, have evidenced an unsafe situation. To avoid such mechanisms, connective systems with tie rods made of glass fiber-reinforced polymer laminates have been designed to be inserted where local verifications are not satisfied. Design, application, and monitoring procedures of this innovative intervention are discussed in detail herein.