Copper water-stop is the most important component for preventing water leak through the joints of hydraulic concrete structures. Concrete structures often experience uneven deformation under gravity and hydrostatic pressure

resulting in tension (or compression)

settlement

and shear deformation (relative displacement) between the two wings of a copper water-stop. Its safety depends on the magnitude of the three-dimensional deformation

which is often judged by the displacement in each direction separately

without considering the coupling of different directions. This paper presents an experimental study of shear tests on copper water-stops under different tensile and settlement displacements

using a test stand that allows independent control of three directions and a total of 40 specimens in two different sizes are designed and fabricated. We examine shear deformation

its variations

and the failure modes of the specimens

and obtain a failure envelope surface in the three-dimensional displacement space. A failure criterion is derived for copper water-stops under three-dimensional displacement for judging the safety of similar water-stops.