  Although recent advances have made it possible to manipulate electromagnetic
and acoustic wavefronts with sub-wavelength metasurface slabs, the design of
elastodynamic counterparts remains challenging. We introduce a novel but simple
design approach to control SV-waves in elastic solids. The proposed metasurface
can be fabricated by cutting an array of aligned parallel cracks in a solid
such that the materials between the cracks act as plate-like waveguides in the
background medium. The plate array is capable of modulating the phase change of
SV-wave while keeping the phase of P-wave unchanged. An analytical model for
SV-wave incidence is established to calculate the transmission coefficient and
the transmitted phase through the plate-like waveguide explicitly. A complete
$2\pi$ range of phase delay is achieved by selecting different thicknesses for
the plates. An elastic metasurface for splitting SV- and P-waves is designed
and demonstrated using full wave finite element (FEM) simulations. Two
metasurfaces for focusing plane and cylindrical SV-waves are also presented.
