To verify a reinforcing effect surely by installing a reinforcing bar and measuring the intensity of stress of the reinforcing bar and/or the quantity of a bridge displaced before the covering of a covering material when the concrete bridge is reinforced by the reinforcing bar and the covering material for the bridge.

Wheel guards 2 are formed at both ends of a floor slab 1 made of reinforced concrete is a bride, and bridge girders 3 are installed to the underside of the floor slab 1. Rrinforcing bars are formed to the rear of the floor slab 1 in a grid shape, and the crosses sections are fixed on the whole surface by tapered fixtures 6, to which wire reinforcing bars 5 fastened by welding are arranged. The wire reinforcing bars 5 are covered with polymer cement mortar so as to cover the whole surface of the wire reinforcing bars 5, and a covering later is formed. The wire reinforcing bars 5 are fixed at that time, load D is placed beforehand on the bridge and a loading test is conducted before the covering later is formed, and the floor-slab reinforcing intensity stress and displacement of the bridge before reinforcement are measured beforehand by a strain gage stuck on the surfaces of the reinforcing bars and a displacement gage mounted on the underside of the concrete bridge.