To provide a novel strip minimizing a gap formed between a reinforcing metal fitting and a groove part, and prolonging progress of corrosion of the reinforcing metal fitting after construction of a regeneration pipe.

An object having a bottom plate part 41, a side plate part 42, and a corner part 43 formed of the bottom plate part 41 and the side plate part 42 is used as the reinforcing metal fitting 4. In the groove part 5 formed between ribs 3 arranged side by side along a one-side face length direction of a substrate 2, the corner part 43 is brought in to contact along one of a pair of in-groove corner parts 53 existing in the groove part 5, the bottom plate part 41 is faced to the substrate 2 composing a bottom face 51 of the groove part 5, and the reinforcing metal fitting 4 is fixed with the side plate part 42 in surface-contact with a side face of the rib 3 composing an inner side wall 52 of the groove part 5.