structures used for troops, combat matériel, and transport to cross obstacles (such as water barriers, ravines, and roads) while traveling along roads or column routes on the field of battle.
There are vehicle, railroad, and pedestrian bridges, as well as railroad-vehicle bridges that permit vehicles and trains to cross at the same time. Bridges are built by engineer, road, and railroad troops using standard materials carried by the troops or using local materials. Easy transportability of bridge elements is important for military bridges, because it makes it possible for engineer units to accompany troops and get to the water obstacles that must be crossed in time. Other important characteristics are the speed with which bridges can be erected by minimal forces, the adaptability of bridge materials and structural elements for use with different kinds of obstacles, minimum vulnerability to weapons, and simplicity of repair under field conditions.
Depending on the type of support, military bridges are classified as floating bridges, fixed-support bridges, or a combination of both.
Floating military bridges may be pack bridges assembled from metal pontoons or barges, or they may rest on individual floating supports (such as pontoons, barges, scows, or boats). They make it possible to erect a bridge crossing quickly in water more than 1 m deep, regardless of the type or configuration of the bottom.
Military fixed-support bridges (wood, metal, piles or a frame) are classified as low level, high level, and underwater. Low-level military bridges have small spans (4–6 m, rarely 10–12 m), ordinarily permit one-way traffic and are designed for short-term use. They are 0.5–1 m above the water surface. High-level military bridges have 30 or more spans and usually provide for two-way vehicle traffic and one-way rail traffic. They are intended for prolonged use and permit ice, floods, and river vessels to pass under them. Dismountable fixed-support military bridges are used as rear bridges for numerous crossings of water obstacles. In submersible military bridges the roadway is 30–50 cm below the water, which gives the bridge a better chance of survival in case of enemy action and makes it difficult for reconnaissance to discover the bridge.
Military bridges combining fixed and floating supports are erected over rivers that are very deep and wide. Mechanized bridges are used for troops to cross narrow obstacles and water barriers on the field of battle and when moving in columns. They are erected by bridge-laying vehicles.
Military bridges were used in the armies of the ancient states. The earliest were floating bridges on light boats carried by the troops (for example, in Assyria, ancient Egypt, and ancient Greece). In 480 B.C., during the Greco-Persian Wars, the Persian Army crossed the Dardanelles on two floating bridges assembled on rowing ships; each bridge was about 1, 200 m long. In the Roman Army military bridges were built on pile supports (for example, across the Rhine in the first century B. C.). During the Middle Ages the art of bridge building fell into decline in Europe and revived again only in the 14th century. During the 15th to 17th centuries floating bridges were built many times across the Volkhov, Dnieper, Don, and other rivers by the Russian Army.
In the early 17th century the Dutch Army introduced bridge equipment called the bridge train, which later spread to other European armies (and to Russia in the early 18th century). A further development was the erection of bridges from structural elements prepared in advance (for example, a floating bridge—constructed of rafts and about 1, 000 m long—across Severnaia Bay in Sevastopol’ during the Crimean War of 1853–56). With the development of railroads, military railroad bridges were built. In the 1860’s a dismountable metal railroad bridge was built in Russia; similar bridges appeared in Germany, France, and other countries during the 1870’s.
During World War I (1914–18) the British Army built tank bridges, which were used to surmount obstacles on the battlefield. During the 1930’s floating bridges made from bridge trains with all-metal pontoons and high-strength steel stringers with large load capacities were developed in the USSR and elsewhere. They were transported on special vehicles. During the Great Patriotic War (1941–45), Soviet troops made extensive use of low-level bridges distinguished by simplicity of design; this type of bridge accounted for 85 percent of the total length of all bridges built. Also used were floating bridges with load capacities of up to 60 tons (more than the load capacity of the floating bridges in the armies of the capitalist countries). On wide rivers, such as the Dnieper, Neman, Dnestr, Vistula, and Oder, combined floating and fixed-support bridges or high-level bridges intended for long-term use were built.
In the postwar years bridge structural elements and bridge-building equipment for erecting bridges quickly have developed in the armed forces of various countries. A significant step forward in this area was the development, in the Soviet armed forces, of pontoon-bridge trains in which the span structure and supports are joined in a single structural element, the pack bridge. Mechanized bridges (tank bridges and bridges for the convoy of troop columns) have developed a great deal.
M. A. KOZLOV