Composite-material casing having an integrated stiffener

A method for manufacturing a fan casing made of composite material for a gas turbine, comprising:

• producing by three-dimensional weaving between a plurality of layers of warp threads and a plurality of layers of weft threads a fiber texture in the form of a strip,
• winding the fiber texture around several superimposed turns on a mandrel with a profile corresponding to that of the fan casing to be manufactured in order to obtain a fiber preform of a shape corresponding to that of the fan casing to be manufactured, and
• densifying the fiber preform by a matrix,
• wherein the fan casing has a revolution solid shape and is constructed and arranged to surround a fan of the gas turbine,
• wherein, during the winding of the last turn of the fiber texture on the mandrel, at least one stiffening element is interposed between a before-last turn and a last turn of the fiber texture, the stiffening element projecting over the outer surface of the before-last turn of the fiber texture and extending over an entire circumference of said before-last turn, the stiffening element having an axial section of omega-type shape, and
• wherein at least some warp threads of the plurality of layers of warp threads in the last turn of the fiber texture present at the level of an area covering said at least one stiffening element have a size or a tex less than the size or tex of the warp threads of the plurality of layers of warp threads present in the other turns of the fiber texture.