Seismic Risk Mitigation of Historical Masonry Towers by Means of Prestressing Devices

Abstract

This work presents the investigation of the efficiency of different prestressing devices as a rehabilitation measure for the seismic risk mitigation of historical masonry towers. As a first phase, the seismic vulnerability of theoretical masonry towers was assessed by means of numerical models validated with information from the literature, observed damage and behavior of these structures due to passed earthquakes (crack pattern and failure mechanisms), and mainly taking into account the engineering experience. Afterwards, the validated models were rehabilitated with different prestressing devices; analyzing the results and concluding which device or the combination of them improved in a better way the seismic performance of the masonry towers. Finally, the methodology will be applied in two historical masonry towers located in seismic areas; the medieval tower “Torre Grossa” of San Gimignano, Italy, and one of the bell towers of the Cathedral of Colima, Mexico.

Numerical Investigation of Four Seismic Upgrading Techniques on a Masonry Bell Tower

“…delamination [16]. In regards to a tower's performance upgrade, very few cases could be found: they consist of the application of horizontal tied rods to close vertical cracks and vertical prestressing tied rods to increase the global capacity under horizontal loads, [17]. As previously stated, the actual stress levels at the base of masonry towers could have a magnitude close to the compression strength of the material and, for this reason, the vertical prestressing could decrease a tower's capacity instead of increasing it.…”