Tokyo Metropolitan Expressway Route 12
|Date Visited: ||October 1996||Contact: ||Dr. K. Nishikawa, Head, Bridge Division, Public Works Research Institute||Summary: ||FiBRA (braided aramid fiber reinforced composite) rods are used as reinforcement in precast concrete deck panels used to eliminate corrosion in the splash zone around an anchorage housing which also serves as a landing and docking area.|
The Rainbow Bridge is a double deck suspension bridge that is 918 m in overall length, with a 570 m main span. The upper level of the steel truss deck carries six toll lanes of the Tokyo Metropolitan Expressway (Daiba Line). The lower deck has a new commuter transit system (connecting Tokyo with Tokyo Teleport Town), toll free roads and a pedestrian promenade.
Fig. B.50. View of Rainbow Bridge at night.
Fig. B.51. Overall dimensions of the bridge.
The southeast anchorage housing has a cantilevered service and boat landing walkway at its base (Fig. B.52) which is constructed from hollow core precast concrete deck panels (Fig. B.53) pre-tensioned with FiBRA rods (aramid fiber composites). These rods were used to eliminate the potential for corrosion and reduce maintenance costs, since the walkway is in the splash zone.
Fig. B.52. Precast concrete walkway at the base of the anchorage.
Fig. B.53. Geometry of a precast concrete deck panel.
Each precast panel is 5 m long, 0.91 m wide and 0.2 m deep. Each is pre-stressed with 10 FiBRA FA9 rigid type tendons. The tendons consist of braided aramid fibers (Fig. B.55) fabricated by the Shinko Wire Company, and the specific bonded tendons used in these panels had a nominal diameter of 9 mm, with a cross-sectional area of 63 mm2, an assured (design) load of 94.1 kN, modulus of elasticity of 68.6 kN/mm2 and an elongational strain of 2%.
Fig. B.54. Placement of panels.
Fig. B.55. Schematic of the FiBRA tendon.