ice bridge

plural ice bridges

1. An ice control structure on a river, to control flowing river ice, that spans the breadth of the river, and may have a traversable roadway on top.
2. A type of ice road, a floating-bridge-like roadway made of floating ice atop a body of water.

   The ice bridge thus successfully inaugurated continued in operation until March 31, when the thaw having begun to affect the ice, the management ordered the track to be dismantled rather than risk accident.

   1941 March, Andrew Paterson, “The Montreal Ice Railway”, in Railway Magazine, page 112

3. A type of ice road, a causeway-like road across a body of water, made of full-depth ice, where from the road surface to the lakebed or riverbed is solid ice.