multispan

Multispan is a term used in civil engineering and architecture to describe a structure that spans more than one intermediate support. The defining feature is the presence of multiple spans, i.e., distances between successive supports such as piers or abutments. The term is most commonly applied to bridges and viaducts, but can also describe elevated roadways, pipelines, aqueducts, and other long-span structures that traverse uneven terrain.

In bridges, a multispan configuration consists of two or more spans between supports. Spans may be simply supported or (more often) continuous, with the superstructure extending across piers. End spans terminate at abutments; interior spans are supported by intermediate piers. The design must account for jointing between spans, bearing types, and potential differential movement.

Advantages of multispan designs include the ability to cross long distances with fewer structural supports and to tailor span lengths to site constraints. Challenges include increased structural indeterminacy in continuous systems, larger joint and bearing requirements, temperature and seismic effects, and maintenance issues such as scour around piers and corrosion at joints.

Construction and inspection considerations include staging for pier construction, foundation work, and alignment of spans. Codes and standards for multispan structures vary by country but generally address loadings, fatigue, vibration, and safety, along with requirements for expansion joints and bearings in long-span systems.

Related terms include multi-span bridges, viaducts, continuous spans, and simply supported spans. In some contexts, multispan is used interchangeably with the hyphenated "multi-span."