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of a bridge, the part of a bridge that extends between the bridge piers and carries various loads, such as transportation vehicles, pedestrians, and winds, which it transfers to the piers.
A span consists of such bearing components as longitudinal beams or trusses, crossbeams or diaphragms, and slabs for the roadway. In arch bridges the main bearing components are the arches, which support the structure above them. Loads carried by spans are transferred to piers through bearing parts. The roadway slab of a span supports a roadbed and pedestrian sidewalks. The surface of the slab is paved with a layer of topping of asphalt or cement concrete and waterproofing. The material used for a span may be a metal, such as an aluminum alloy or steel, plain or reinforced concrete, native stone, or wood.
The span is the most important part of a bridge. The structural design of a bridge and its static diagram depend on the static diagram of the span. The span may be of the girder, frame, arch, suspension, guy, or combination type. The general architectural composition of a bridge is essentially dependent on the type of span. Ordinarily a span is rectilinear as viewed from the top, although the spans of modern bridges, viaducts, and overpasses over the junctions of transportation lines may have more complicated shapes and be spiraled, ringed, or branched.
The static diagram and the structural material used determine the way in which a span is constructed. Spans are usually built from prefabricated units manufactured in specialized plants or yards.
in buildings and structures, the distance between the neighboring supports of horizontal structural elements. There are spans, for example, between the columns that support a roof truss and between the piers that support a bridge span. Standardized span dimensions that conform to the Unified Modules System are currently used in construction in the USSR.