Which category includes span lengths greater than 400 ft?

• A. Long Span Bridges
• B. Short Span Bridges
• C. Culverts L ≤ 20ft
• D. Medium Span Bridges

Answer: (A)

Span length categories help engineers choose appropriate design approaches. When a bridge’s clear span exceeds about 400 ft, it’s considered a long-span bridge because the forces, stiffness requirements, and construction methods differ significantly from shorter spans. Long spans often require specialized solutions such as cable-stayed or suspension systems, or very long continuous girders to manage deflection and stability over great distances. Short and medium spans cover smaller distance ranges and use more conventional detailing and connections, while culverts with L ≤ 20 ft are drainage structures, not road or rail bridges, so they don’t fall into the bridge span classifications. Therefore, anything exceeding 400 ft is categorized as long-span.