Even though the thickness of the soil specimen is sometimes
used to normalize horizontal displacements for direct shear
tests to permit comparisons with the results from simple shear
tests reported in the literature, the results in the present study
show that the thickness of the sand specimen has an insignificant
effect on the interface behavior between FRP and OTWA.
This is explained by the fact that the failure zone is of
limited thickness for interface shear tests (Yoshimi and Kishida
1982).