The Tyngsborough Bridge is a steel tied-arch bridge located in Tyngsborough, Massachusetts and carries Route 113 over the Merrimack River. With a span of 547 feet, it has the longest span of any steel rib through arch bridges in Massachusetts. It is also the 2nd oldest steel rib through arch bridge in the state. The bridge is center hinged and features pratt-type trussing.
The arch bridge in Tyngsborough, Massachusetts, with the Temporary bridge alongside it in 2006
The Tyngsborough Bridge, as seen from alongside the Merrimack River.
A tied-arch bridge is an arch bridge in which the outward-directed horizontal forces of the arch(es) are borne as tension by a chord tying the arch ends rather than by the ground or the bridge foundations. This strengthened chord may be the deck structure itself or consist of separate, independent tie-rods.
The Fort Pitt Bridge. The arches terminate atop slender raised piers and are tied by the road deck structure.
A rail bridge in Argos, Peloponnese featuring multiple tied arches.
Erkkilä Bridge in Tampere, Finland
Fremont Bridge in Portland, Oregon.