Why do bridges use steel cables?
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Answer: High tensile strength needed
High tensile strength needed ✓ — Correct! Suspension bridges use steel cables because they have exceptional tensile strength—resistance to being pulled apart. Bridge cables support the deck's weight through tension. Steel cables can handle enormous pulling forces while being much lighter than solid steel beams. Cables in suspension bridges can support tens of thousands of tons while remaining flexible during wind and movement.
Cheaper than solid beams — Wrong. While cables can be more efficient than beams for certain designs, they're used primarily for their tensile strength. Suspension bridges need materials that resist pulling forces—steel cables excel at this while being lighter than solid beams capable of the same load.
Easier to paint and maintain — Wrong. Maintenance isn't why cables are used. Steel cables are chosen because of their exceptional tensile strength—they can support enormous weight through tension while being lighter than equivalent solid beams. Paint and maintenance are considerations, not reasons for the design choice.