Beam for a containment structure

A method of manufacturing a casing for a gas turbine engine which engine casing includes a structure for positioning and supporting a fabric radially outwardly of a working medium flow path in a gas turbine engine to contain paritcles having a radial velocity, and includes a fabric disposed about the structure, the method including:

• disposing a first wall axially and radially with respect to a second wall such that the second wall is axially aligned with the first wall and is spaced radially from the first wall leaving a gap therebetween;
• forming a plurality of annular plates having an inner leg, an outer leg, and a rib extending in a generally radial direction between the inner leg and the outer leg such that a straight line passes through theouter leg and the inner leg;
• inserting at least one annular plate into the gap between the first wall and the second wall and axially spacing each annular plate from any adjacent annular plates;
• joining each of the annular plates to the inner wall and the outer wall;
• and,
• disposing a fabric about the structure;
• wherein the step of inserting each of the annular plates includes the step of locating each annular plate with respect the first wall and the second wall by attaching each leg to the associated wall at circumferentially spaced locations to place the leg in abutting contact with the wall such that a straight line passes through the outer leg, the inner leg and the walls, and wherein the step of joining the outer leg to the first wall and the inner leg to the second wall is performed after the step of inserting the annular plates and includes the step of mounting the subassembly of the inner wall, the outer wall and the annular plates in a fixture and positioning a welder outwardly of the outer wall to pass a stream of energy on a line through the outer wall, the outer leg, the inner leg and the inner wall to provide a circumferentially continuous weld between the leg and the wall.