Seismic Vulnerability Reduction of Historical Masonry Towers by External Prestressing Devices: Fid-Bau Portal

Seismic Vulnerability Reduction of Historical Masonry Towers by External Prestressing Devices

Preciado Quiroz, Adolfo

This thesis describes a methodology to manage the seismic risk of historical masonry towers, including risk assessment and its reduction. First chapters describe the main aspects determining the earthquake hazard of a site, the structural vulnerability of towers and the recommended in literature to manage seismic risk. Since the seismic hazard is unavoidable, in this thesis the seismic risk reduction is attained by decreasing the structural vulnerability of towers by implementing prestressing devices. They are vertically and externally located inside the towers to give to the retrofitting the characteristic of reversibility, respecting in all senses the architectonic and historical value of the structure. This work addresses two main key stages on the seismic risk management of towers. The first stage corresponds to the assessment of seismic risk by combining intensive numerical simulations and a suitable masonry model. To obtain models more reliable and representative they are validated with key-behavioural characteristics reported in literature, observed damages and calibrated with experimental data. Prestressing intends to improve the seismic performance of towers by reducing the expected damage with the application of a pre-compression to the masonry to increase strength, ductility, energy dissipation and confinement, achieving with these the seismic risk reduction. The risk assessment of historical towers and the possible achievement of the risk reduction are the main characteristics of the proposed methodology. The second key stage corresponds to the validation of the proposal in two real historical towers located in seismic zones of Mexico and Italy. Finally, advantages and limitations of this proposal in the seismic risk management of historical masonry towers are described.