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A suspension bridge is one where cables (or ropes or chains) are strung across the river (or whatever the obstacle happens
to be) and the deck is attached or 'suspended' from these cables. Modern suspension bridges have two tall towers through
which the cables are strung. Thus the towers are supporting the majority of the roadway's weight.
Compression
The force of compression pushes down on the suspension bridge's deck, but because it is a suspended roadway, the cables
transfer the compression to the towers which dissipate the compression directly into the earth where they are firmly
entrenched.
Tension
The supporting cables, running between the two anchorages, are the lucky recipients of the tension forces. The cables are
literally stretched from the weight of the bridge and its traffic as they run from anchorage to anchorage. The anchorages
are also under tension, but since they, like the towers are held firmly to the earth, the tension they experience is
dissipated.
Almost all suspension bridges have, in addition to the cables, a supporting truss system beneath the bridge deck (a deck
truss). This helps to stiffen the deck and reduce the tendency of the roadway to sway and ripple.
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