Suspension Bridges
A suspension bridge has two or more towers, and the deck is suspended with cables. A suspension cable is draped between the towers, with smaller suspenders connecting the deck and the suspension cable. The suspenders transfer force from the deck to the suspension cable, which in turn transfers forces to the towers, while the towers transfer forces to the ground. Suspension bridges are long bridges. In a suspension bridge, special measures must be taken to combat forces from wind. Stiffness and weight are two important factors. Deck-stiffening measures can help combat destructive forces from wind. According to Deflection Theory, as the deck gets longer and therefore heavier, less reinforcing stiffness in needed for the deck. The weight of the bridge pulls it down, resisting forces pushing it in other directions.
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