Seismic retrofit of masonry with innovative materials for strengthening and repair
- Autores: Larisa Garcia Ramonda Estevez
- Directores de la Tesis: Pere Roca Fabregat (dir. tes.), Luca Pela (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2020
- Idioma: español
- Materias:
- Texto completo no disponible (Saber más ...)
- Resumen
As one of the main historical construction materials, masonry is abundant among the architectural heritage of earthquake-prone areas of the Mediterranean countries. Earthquake mitigation approaches are now focusing on strengthening solutions based on compatible and environmentally friendly repair materials, such as Textile Reinforced Mortar (TRM). These solutions have recently evidenced their efficiency to improve the in-plane lateral strength and displacement capacity of masonry buildings, which are the most significant parameters considered in the seismic assessment. Notwithstanding the increasing interest risen by the potentiality of TRM strengthening systems, limited research has been done about the structural response of TRM applied on historical masonry as a seismic retrofitting or post-earthquake repair.
This thesis presents an extensive experimental programme on masonry walls composed of handmade clay bricks and low strength lime-based mortar, a recurrent typology for historical buildings. The walls were strengthened with four different TRM strengthening solutions, and one joint repointing solution with Near Surface Mounted (NSM) helical rebars. The main aim of the experimental campaign was to deepen the understanding of the in-plan behaviour of strengthened masonry and to accurately capture the global and local response of strengthened masonry walls, emphasising on the identification of damage levels and the influence of different configurations of TRM strengthening solutions on the in-plane response.
Diagonal Compression Tests (DCT) and quasi-static Shear Compression Tests (SCT) were per- formed to investigate the in-plane response of strengthened masonry and validate TRM as a seismic retro¿tting technique. In addition, a post-earthquake repair methodology has been also investigated. The methodology consisted on repairing damaged unreinforced masonry walls with di¿erent techniques, such as crack repointing and ”scuci-cuci”, and strengthened them with basalt TRM strengthening system. The experimental results show the suitability of the proposed solutions and highlight the e¿ectiveness, to di¿erent extents, of the investigated systems in increasing the resistance and ductility of unreinforced brick masonry. The results also show that the presence of TRM strengthening systems has a signi¿cant impact on the failure mode of the walls and hence, the displacement capacity, energy dissipation, strength and sti¿ness degradation of the global response. In turn, TRM strengthening systems have not signi¿cantly in¿uenced the initial sti¿ness and damping. The experimental results were compared to the analytical ones assessed with the available formulations provided by the Italian guideline CNR-DT 200 (2013). The comparison evidenced good agreement; however, particular attention has to be paid, when de¿ning the parameters, to the failure mode associated to the TRM strengthening systems.
Finally, a methodology is proposed that pursuits the correlation between both testing methodologies, DCT and SCT, to effectively assess the in-plane parameters that govern the masonry's behaviour in both unreinforced and strengthened configurations. From the correlations investigated, it became clear that the in-plane response can be characterized by means of an equivalent tensile strength that takes into account the joint contribution of the masonry and reinforcement. This correlation shed light on the interpretation of DCT while validating it as an affordable testing methodology to evaluate the tensile strength of masonry.
