A Bailey bridge is a type of portable, pre-fabricated, truss bridge. It was developed in 1940–1941 by the British for military use during the Second World War and saw extensive use by British, Canadian and American military engineering units. A Bailey bridge has the advantages of requiring no special tools or heavy equipment to assemble. The wood and steel bridge elements were small and light enough to be carried in trucks and lifted into place by hand, without the use of a crane. The bridges were strong enough to carry tanks. Bailey bridges continue to be used extensively in civil engineering construction projects and to provide temporary crossings for pedestrian and vehicle traffic. A Bailey bridge and its construction were prominently featured in the 1977 film A Bridge Too Far.

Parts of the bridge

The basic Bailey bridge is made up of three main parts, the floor, the stringers and the side panels. The floor of the bridge is made up of a number of 19-foot-wide transoms (5.8 m) that run across the bridge. Across the bottom of these, forming a square, are 10-foot-long stringers (3.0 m). The bridge's strength is provided by the panels on the sides. The panels are 10-foot-long (3.0 m), 5-foot-high (1.5 m), cross-braced rectangles. Each weighs 570 pounds (260 kg), and can be lifted by six men.

Application

Generally used for urban bridges or highway viaducts and overpasses with small spans

Reinforced concrete: medium and small span

Prestressed reinforced concrete: large span

Straight leg frame (door type) and slant leg frame: medium and small span

T-shaped rigid frame, continuous rigid frame: large span· Road Bridges· Pedestrian Bridges· Railway Bridges· Steel Truss Bridge· Beam Bridges· Steel Bailey bridge· Structural Steel Box Bridge· Highway Bridges· Composite Beam Bridge· Cable-Stayed Bridge· Floating Bridge etc.

Finally

The success of the Bailey bridge was due to the simplicity of the fabrication and assembly of its modular components, combined with the ability to erect and deploy sections with a minimum of assistance from heavy equipment. Many previous designs for military bridges required cranes to lift the pre-assembled bridge and lower it into place. The Bailey parts were made of standard steel alloys, and were simple enough that parts made at a number of different factories could be completely interchangeable. Each individual part could be carried by a small number of men, enabling army engineers to move more easily and more quickly than before, in preparing the way for troops and materiel advancing behind them. Finally, the modular design allowed engineers to build each bridge to be as long and as strong as needed, doubling or tripling up on the supportive side panels, or on the roadbed sections.