John Roebling’s initial studies of wire rope endurance and the creation of Three Size ("Warrington") construction

Summary

During the 1850's responding to ever increasing demand, Swan and Roebling devised the first wire ropes made with 3 varying wire diameters, Experiments established the concept of combining different wire diameters into a single strand all with equal lay length. Their basic concept, now called OWarringtonO is still used today. This historical paper summarises the first North American endurance studies, and other developments, leading to the Three-Size concept._ Also included is speculation about why Swan and Roebling never attempted to get a patent on their discovery.

Author: D. Sayenga