Tomasso Dec 10, 2019:

Shear key contains rebar page 1052 https://escholarship.org/content/qt5zs8f2wr/qt5zs8f2wr.pdf?t...

quote' This increase in resistance is due to the tension force
developed in the vertical dowel bars, which lean sideway as
the horizontal displacement of the shear keys increases. This
phenomenon is captured by incorporating the geometric
nonlinearity of the bars in the analyses. The final load drops
exhibited by both shear keys are due to the fracture of the
bars. Unquote,
One hundred years ago, a key way with shear key was a channel filled with soft metal to prevent damage to larger parts, a safety Key Way filled with malleable concrete reinforced with soft metal, bars , etc is Shear Key Way and has a special meaning perhaps.

Tomasso Dec 10, 2019:

The use of the term ***shear key ** is possibly misleading, if one looks at ; http://onlinepubs.trb.org/onlinepubs/nchrp/docs/nchrp12-69_f... it says in part;


6. If the connector is to be used to resist shears due to the elimination of
differential camber before grouting the keyway, both the shear strength of
the metal connector and the resistance to shear of the anchors should be
calculated using
Vn = Na (2.5de - 3.5) kip
must not be less than twice the calculated shear per connector due to the
leveling operation.
In the above,
' c f = Compressive strength of concrete;
T1 = anchor force required to develop a shear resistance of 16 kip, in a
length s of grouted connection
T2 = maximum probable tension force per connector due to restraint of
lateral shrinkage in bridge deck;
a = maximum inclination of sloping faces of grout key (see Figure 4

((It seems the term ***key Way ** is used in a special sense, it is a long depressed groove, or other area, in to which soft materials are placed, materials that will SHEAR or tear, deform, plastic deformation, such materials can be REBAR, Rebar used for tthe shearing potential, when placeed in a groove made between two