Intermittent spigot joint for gas turbine engine casing connection

A gas turbine engine casing assembly, comprising:

• a first annular case having a central axis and an annular seat at one of a front end and a rear end of the first annular case,
• the annular seat having an annular surface facing toward the central axis and a surface angled relative to the central axis;
• a second annular case connected coaxially to the first annular case and having an annular projection received in the annular seat, the annular projection having:
• a surface contacting the surface angled relative to the central axis of the annular seat, and
• an annular surface engaging the annular surface of the annular seat at a plurality of locations that are distributed circumferentially along the annular surface of the annular seat;
• and
• a plurality of scallops circumferentially spaced from one another and formed on at least one of the annular surface of the annular projection and the annular surface of the annular seat, a given scallop of the plurality of scallops being between a given pair of locations of the plurality of locations, wherein at least one of the scallops is located symmetrically about a radial central axis of a structural member projecting from the at least one of the annular surface of the annular projection and the annular surface of the annular seat.