Abstract
The evaluation of the shear behavior of masonry walls is a first fundamental step for the assessment of existing masonry structures in seismic zones. However, due to the complexity of modelling experimental behavior and the wide variety of masonry types characterizing historical structures, the definition of masonry’s mechanical behavior is still a critical issue. Since the possibility to perform in situ tests is very limited and often conflicting with the needs of preservation, the characterization of shear masonry behavior is generally based on reference values of mechanical properties provided in modern structural codes for recurrent masonry categories. In the paper, a combined test procedure for the experimental characterization of masonry mechanical parameters and the assessment of the shear behavior of masonry walls is presented together with the experimental results obtained on three stone masonry walls. The procedure consists of a combination of three different in situ tests to be performed on the investigated wall. First, a single flat jack test is executed to derive the normal compressive stress acting on the wall. Then a double flat jack test is carried out to estimate the elastic modulus. Finally, the proposed shear test is performed to derive the capacity curve and to estimate the shear modulus and the shear strength. The first results obtained in the experimental campaign carried out by the authors confirm the capability of the proposed methodology to assess the masonry mechanical parameters, reducing the uncertainty affecting the definition of capacity curves of walls and consequently the evaluation of seismic vulnerability of the investigated buildings.
Highlights
Masonry buildings are a large part of a built environment, especially in historical towns
Seismic performance, which is commonly evaluated through nonlinear static analysis, is highly dependent on assumptions related to the main mechanical parameters of the material: shear modulus, G; elastic modulus, E; shear strength, τk; global stiffness; and displacement capacity
Sensitivity studies carried out by the authors [1,5,6] emphasized that the seismic risk index IR, which summarizes the seismic performance of the structure, could significantly vary depending on the assumptions about the shear behavior of masonry walls
Summary
Masonry buildings are a large part of a built environment, especially in historical towns. Since these structures were mostly built according to empirical rules and without following specific seismic design provisions, they are often characterized by a high seismic vulnerability. The characterization of the shear behavior of each wall is the basis for a sound assessment of the seismic vulnerability of a masonry building. Sensitivity studies carried out by the authors [1,5,6] emphasized that the seismic risk index IR, which summarizes the seismic performance of the structure, could significantly vary depending on the assumptions about the shear behavior of masonry walls
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