What It Means
An arch bridge is a structure in which load is carried primarily in compression along a curved arch from crown to springing, with horizontal thrust resisted by abutments founded on rock or piles, or by tie members in tied-arch configurations. Arches are among the oldest bridge forms, dating to Roman masonry construction, and remain in use today in steel, reinforced concrete, and occasionally stone. Types include deck arch (roadway above the arch, common in river crossings with rocky banks), through arch (roadway passes through the arch, often with tied construction), half-through arch, and tied arch (horizontal tie member resists thrust, allowing arch to be founded on piers without abutment rock). Notable U.S. arch bridges include the New River Gorge Bridge (West Virginia, 1977, 1,700-foot span, one of the largest steel arch bridges in the world), the Hoover Dam Bypass (Nevada/Arizona, 2010, concrete arch), and numerous tied-arch bridges on the Interstate System. Arch bridges represent roughly 2% of the U.S. NBI inventory but are often signature structures on major river crossings. Tied-arch bridges are fracture critical because the tie member is a non-redundant steel tension element, failure of the tie would cause collapse. The 2013 Skagit River Bridge collapse in Washington State, caused by an over-height truck striking a through-truss portal, highlighted that older tied-arch and through-truss structures often have limited vertical clearance and minimal damage tolerance. Arch bridge inspection emphasizes the tie, hanger cables (for through-arch and tied-arch), arch rib condition, and abutment stability. Rehabilitation often involves tie replacement, hanger cable replacement, and deck reconstruction while preserving the historic arch ribs.
Frequently Asked Questions
What does "Arch Bridge" mean?
A bridge that carries load primarily through compression along a curved arch, transferring forces to abutments or piers at the springings.
Why does Arch Bridge matter for bridge safety?
An arch bridge is a structure in which load is carried primarily in compression along a curved arch from crown to springing, with horizontal thrust resisted by abutments founded on rock or piles, or by tie members in tied-arch configurations. Arches are among the oldest bridge forms, dating to Roman...