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36 Ability to detension, inspect, and retension individual Percent of Bridges 100.0 80.0 strands; ability to add strands to each cable or cable 60.0 U.S. Canada group (5%). 40.0 20.0 0.0 FABRICATION AND ERECTION OF STAY CABLES yes no not known Database Useful? As discussed in the previous section, stay cables can be either shop- or field-fabricated. In United States practice, and espe- FIGURE 52 Would a national database of stay cable cially in recent years, field fabrication has been more com- information be useful? mon. The shop-fabricated cables come with the entire cable, including anchorages and sheathing pre-assembled and coiled I like the idea of hermetically sealed, ungrouted cables on reels. The cables are then uncoiled and lifted into place. with fiber optic sensors throughout or exposed wire that If fillers are required, they are generally placed or injected can be directly inspected. after stressing of cables. In this arrangement, the entire cable Provide access on inside and outside of tower anchorage. must be stressed with one large hydraulic jack. The field- Fiber optic strain gauges and redundant systems. fabrication method generally involves inserting strands one We would recommend the development of individual by one into the wedge plate in the bottom anchorage and, strand monitoring capabilities that encompass the strands through various methods developed by cable suppliers, the from anchorage to anchorage. strands are pulled through the top wedge plate. The strands For non-box bridges, an inspection traveler should be in- are typically stressed one at a time using a single-strand stalled on the cable-stayed bridge. This should be done jack. If required, the cable fillers (e.g., grout) would then be by the owner. injected into the anchorage zones (in the case of bond socket) Not possible that the cable suppliers can do any more. or the entire cable.