262 Structural Cables 2621 Steel Wires

Cables are naturally the most important element of a cable-supported bridge. Although eye-bar chain was used in the early days and now the use of new composite materials is going to increase for small-span bridges, the material most frequently employed in modern bridge cables is cold-drawn high-strength steel wires, which have a diameter of 3 to 7 mm and ultimate tensile strength of 1.5 to 1.9 GPa.

As shown in Figure 26.2, the tensile strength of the steel wires used in suspension bridge cables increased up to 1.8 GPa in constructing the world's longest bridge, Akashi Kaikyo, which was completed in 1998 by adding an appropriate amount of silicon. On the other hand, the wire element of the seven-wire strand as used extensively for prestressed concrete, consisting of a straight core wire surrounded by a single layer of long-pitch six wires, has already had a higher tensile strength between 1.8 and 1.9 GPa.

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FIGURE 26.2 Tensile strength of galvanized steel wires.

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FIGURE 26.2 Tensile strength of galvanized steel wires.

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