Incremental Method for Sag-Tension Calculations

This paper presents an analytical method for calculating sags, tensions, and lengths of overhead cables. The method is applicable to both level and non-level spans; self contained, not requiring the use of precalculated data or functions; and adaptable to both cables with constant modulus of elasticity, such as steel or copper, and cables such as steel reinforced aluminum cable where stress-strain curves must be resorted to. Included in the method is a direct calculation of the horizonital component of tension in a span where the tension at either support is known. Increments of length of cable are calculated rather than total lengths, thus permitting adequate accuracy to be had using a 10-inch slide rule.