Arches use a curved structure that provides a high resistance to bending forces. Unlike girder and truss bridges, both ends of an arch are fixed in the horizontal direction (i.e., no horizontal movement is allowed in the bearing). Thus when a load is placed on the bridge (e. G. , a car passes over it) horizontal forces occur in the bearings of the arch. These horizontal forces are unique to the arch and as a result arches can only be used where the ground or foundation is solid and stable.

Like the truss, the roadway may pass over or through an arch or in some cases both Structurally, there are four basic arch types: hinge-less, two-hinged, three hinged, and tied arches.

The three-hinged arch adds an additional hinge at the top or crown of the arch. The three-hinged arch suffers very little if there is movement in either foundation (due to earthquakes, sinking, etc. ) However, the three-hinged arch experiences much more deflection and the hinges are complex and can be difficult to fabricate. The three-hinged arch is rarely used anymore.