A Bailey bridge is a factory made truss bridge. It was made in small sections that could be easily moved and put together on site. It was developed by the British during World War II for military use.
A Bailey bridge did not need special tools or heavy equipment to put into place. The wood and steel bridge parts were small and light enough to be carried in trucks and lifted into place by hand. The bridges were strong enough to carry tanks. Bailey bridges continue to be used in building projects and to provide temporary crossings for people and vehicles.
It was designed by a British engineer, Donald Bailey. The British army tested different bridge designs in 1941–1942, including a suspension bridge and a stepped arch bridge. The flat truss bridge was the most successful. An early test model of the Bailey flat truss bridge is still in place over Mother Siller's Channel in Dorset. The Bailey bridge was first used by the army in Tobruk in 1942. The US Army built many of the bridges for use after the D-Day landings in France.