Columns, Piers & Towers
These structures transfer the loads from the bridge to the foundation,
which then pass it onto the ground. They are mainly used to support
the bridge deck.
Piers are columns that are placed in water. Because water flowing past the pier will wash away the soil underneath, rip-rap (large pieces of interlocking rocks) are placed to prevent this from happening.
Towers are unique to cable-stayed and suspension bridges; they tend to rise above the bridge deck a considerable distance to support it.
See also abutments and foundations.