A retaining plate (30) made from a rigid material having tips on each of the two faces of same, the tips of each of the faces of a length of between 1 and 3 mm making an angle in the forward direction with the face of between 30° and 60°. The retaining plate is secured by the tips of one of the faces of same at the final end (28) of a first reinforcing strip (26) already positioned on the degraded portion of a pipe, and secured to the initial end (32) of a second reinforcing strip to be wound following the first reinforcing strip by the tips of the other face, said tips being tilted towards the initial end (32) of the second reinforcing strip.