abutment

thumb|The superstructure of Kurobe Dam in Japan rests on opposing concrete abutments thumb|Abutment for a large steel arch bridge thumb|Brick abutment supporting disused tramway over the Yass River in [[Yass, New South Wales]] thumb|right|Cream (colour)|Cream-colored concrete abutment gives vertical support to both the small iron rail bridge and earthen fill of the bridge approach embankment at Old Town Station Staten Island Railway - Staten Island, New York

An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end that provide vertical and lateral support for the span, as well as acting as retaining walls to resist lateral movement of the earthen fill of the bridge approach. Multi-span bridges require piers to support ends of spans unsupported by abutments. Dam abutments are generally the sides of a valley or gorge, but may be artificial in order to support arch dams such as Kurobe Dam in Japan.