Similitude laws of multi-storey masonry buildings tested

Earthquakes and other stressors on buildings pose a threat to their structural integrity that endangers human life. It is effective to be able to calculate the behavior of buildings and test with small-scale models. A shaking table test is an effective approach to characterize the seismic behavior of masonry structures. Models usually need to be reduced in scale due to their weight and the capacity of shaking tables. Similitude laws such as Cauchy and Cauchy-Froude laws are often used for scale reduction (Table 1).

However, the accuracy of the similitude laws has not been fully examined especially in terms of nonlinear behavior including maximum responses (e.g. base shear force and displacement) and damage distribution patterns. Therefore, it was necessary to test if reduced-scale models properly capture the critical response of the full-scale structures. The paper, Comparison of Similitude Laws Applied to Multi-Storey Masonry Structures with Flexible Diaphragms by Associate Professor Yohei Endo of Shinshu University with Pere Roca of the Technical University of Catalonia examined the applicability of Cauchy and Cauchy-Froude laws (Figure 1).

Although the application of the Cauchy law is straightforward, this study found that it may be inadequate for heavy structures unless gravity is scaled (Figure 2-3). Cauchy-Froude law does not need to scale acceleration although the density of materials must be scaled. This is typically done by adding masses. However, flexible diaphragms may not uniformly distribute the weight of the added masses to walls.

This paper can be used as a reference for the shaking table tests of reduced-scale masonry structures, especially during the design process. In order to increase the accuracy of reduced-scale tests for use in engineering fields shaking table test will be performed in 2022 based on the findings of this paper.

Funding
This work was supported by the Japan Society for the Promotion of Science 18KK0124.