Span is a section between two intermediate supports, e. g. of a beam or a bridge. A bridge is a Structure built to span a Gorge, Valley, Road, railroad track, River, Body of water A span can be made of a solid beam or of a rope. The first kind of span is used for bridges, the second one used for power lines, overhead telecommunication lines, some type of antennas or for aerial tramways. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into An aerial tramway is a type of Aerial lift in which a cabin is suspended from a cable and is pulled by another cable

Side view of a simply supported beam (top) bending under an evenly distributed load q (bottom).

The span is a significant factor in finding the strength and size of a beam as it determines the maximum bending moment and deflection. This article is about structural behavior For other meanings see Bending (disambiguation. In Physics, the moment of force (often just moment, though there are other quantities of that name such as Moment of inertia) is a Pseudovector The maximum bending moment and deflection in the pictured beam is found using:

moment:   Mmax = 1/8 · q · L2
deflection: fmax = 5/48 · Mmax· L2 / (E · I)

From this it follows that if the span is doubled, the maximum moment (and with it the stress) will increase four times, and deflection will increase sixteen times. Stress is a measure of the average amount of Force exerted per unit Area.

For remarkable long-distance rope spans, used as power line, antenna or for aerial tramways, see List of spans. The following is a list of remarkable spans either used for powerline crossings of rivers sea straits or valleys as antenna or for aerial tramways