Beconcini Maria Luisa, Croce Pietro, Formichi Paolo, Landi Filippo, Puccini Benedetta
Department of Civil and Industrial Engineering-Structural Division, University of Pisa, 56122 Pisa, Italy.
Materials (Basel). 2021 Apr 29;14(9):2313. doi: 10.3390/ma14092313.
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.
评估砌体墙的抗剪性能是评估地震区现有砌体结构的首要基本步骤。然而，由于模拟试验行为的复杂性以及历史建筑中砌体类型的多样性，砌体力学性能的定义仍然是一个关键问题。由于进行现场测试的可能性非常有限，而且往往与保护需求相冲突，砌体抗剪性能的表征通常基于现代结构规范中针对常见砌体类别提供的力学性能参考值。本文介绍了一种用于砌体力学参数试验表征和砌体墙抗剪性能评估的组合试验方法，以及在三道石砌体墙上获得的试验结果。该方法包括在被研究墙体上进行的三种不同现场测试的组合。首先，进行一次扁千斤顶试验以得出作用在墙体上的法向压应力。然后进行两次扁千斤顶试验以估算弹性模量。最后，进行所提出的抗剪试验以得出能力曲线并估算剪切模量和抗剪强度。作者开展的试验活动所获得的初步结果证实了所提出方法评估砌体力学参数的能力，减少了影响墙体能力曲线定义的不确定性，从而降低了对被研究建筑物地震易损性评估的不确定性。
