Multispannato

Multispannato is a term used in civil engineering and architecture to describe a structure whose horizontal span is divided into multiple adjacent openings, or spans. A multispannato bridge or viaduct consists of a series of spans supported by piers or abutments, rather than a single continuous span. The spans may be of equal length or varied, and the overall length is the sum of the individual spans. The concept can apply to arches, girders, or other structural systems and is common in both historic and modern constructions.

Applications and typology: Multispannato configurations are typical for bridges, viaducts, aqueducts, and covered structures that must cross rivers, valleys, or other obstacles. They allow standardised segment design and easier adaptation to site conditions. Historically, multi-span masonry arch bridges were common, while contemporary examples often use reinforced concrete or steel girders.

Design and construction considerations: Each span rests on piers and abutments, with joints between spans handling movements and expansion. Depending on the structural system, spans can be connected by continuous girders or by discrete, individual elements. Materials vary from traditional masonry to modern concrete and steel, with design addressing load transfer, stiffness, expansion joints, drainage, and, in seismic regions, lateral resistance. The use of multiple spans can simplify construction and maintenance by isolating problems to a single span, but it increases the number of piers, which affects hydraulic flow, navigation, and environmental impact.

See also: Bridge, Viaduct, Arch bridge, Girder bridge, Span.