Abstract: Outer cables disposed in a box girder in the longitudinal direction of a box girder bridge to prestress the box girder each have a transparent sheath made of a transparent polyethylene resin, vinyl chloride resin, polypropylene resin or the like, thereby allowing the grouting condition in the sheath to be inspected reliably and easily. If a colored grout is filled, the filling condition can be inspected even more reliably and easily. In addition, it is possible to readily find a portion left unfilled after the grout has hardened and to refill it for repairing by using openings for injection and ejection made at each side of the void left.

Abstract: A cable protecting tube having high transparency and allowing the filling condition of mortar therein to be visually observed from the outside as well as exhibiting high pressure resistance is provided. A cable protecting tube for accommodating a cable and for filling with mortar includes a protecting tube (1) having smooth inner and outer surfaces formed from an ionomer resin excellent in transparency, and a spiral or mesh-shaped reinforcing member (2) for reinforcing the protecting tube. The reinforcing member (2) may be buried in the protecting tube (1). The protecting tube (1) is not limited to the smooth-walled tube but may be a spirally corrugated tube.

Abstract: A joint made between prestressing strands with a prestressing strand coupler is covered with a transparent coupler sheath having a retarded-hardening resin filling material injection opening and discharge opening provided in a tube wall thereof, and a resin filling material is injected into the transparent coupler sheath from the injection opening to fill the coupler sheath with the filling material. Thereafter, the whole outer peripheral portion of the prestressing strand joint, including the coupler sheath, is embedded with placed concrete. Tension is applied to the prestressing strands after the concrete has hardened and before the resin filling material hardens, thereby completing an excellent prestressing strand joint structure. According to the present invention, the filling condition of the resin filling material in the coupler sheath around the prestressing strand joint can readily be confirmed by visual observation.