Page 18 - Wire Rope News & Sling Technology - October2019
P. 18

continued from page 16                                                ously a better engineer than a farmer,
         the Tournon Bridge was larger than                                    was soon recognized for his skills and
         the Saint Antoine Bridge.                                             knowledge.  He  was  asked  to  work  on
           Suspension  bridges made with  iron                                 improving the  hoisting  system of the
         wires  were  very  advantageous. They                                 Allegheny Portage Railroad, which was
         were  hugely successful,  and a very                                  then fitted with a hemp rope. First he
         large number of such bridges were built                               tried to use the Seguin cable (made of
         up until 1850. These ropes were fulfill-                              parallel wires). This was unsuccessful
         ing the needs for suspension bridges.                                 because it had not been designed to be
                                                                               wound onto a drum.
         HISTORY CONTINUES IN GERMANY                                            He looked for another solution.  So,
         AND THEN IN ENGLAND AROUND                                            in 1841 he developed a wire rope with
         THE HOISTING SYSTEMS                                                  7 strands of 19 wires (6 strands twist-
           The solution for hoisting systems was                               ed in a helix around a core which is a
         developed by Julius Albert who was a                                  strand with  the same construction  as
         mine engineer at the Clausthal mine in                                the external strands). It worked excel-
         Germany. This is the first multi-strand                               lently. The architecture  of this rope,
         rope in history.                                                      which was at first manually produced
           The wire rope is made with several                                  in Saxonburg, is very similar to that of
         strands.  Each  strand is  made of  sev-                              the Newall rope.
         eral wires twisted according to a helix.   John August Roebling         The wire rope was so successful that
         Several strands are then twisted on the      Photo courtesy of The Brooklyn Museum.  Roebling had to produce a closing ma-
         same way to form the wire rope                                        chine (with a vertical main shaft, as op-
           The  Albert rope was  made with 3   a textile core, which was fully produced   posed to Newall’s, which had a horizon-
         strands of 4 wires. The diameter of the   on a closing machine.       tal shaft), and in 1849 he built a brand
         rope was 18 mm and the diameter  of                                   new factory in Trenton, New Jersey to
         the wires was 3.5 mm.              HISTORY IS ALSO BEING              produce wire ropes.
           This rope was installed July 23, 1834   WRITTEN IN THE US             Starting in 1845, John August Roe-
         in a shaft of 484 mm depth at the Caro-  John  August  Roebling  received  his   bling was also involved in civil  engi-
         line mine close to Clausthal.      civil  engineer  diploma at Berlin  Uni-  neering work. He began by renovating
           The rope invented in Germany, at   versity,  where  he  learned  about Na-  existing bridges, and in 1849 he built
         that time was produced manually. Lat-  vier’s work,  and the reports of Marc   the aqueduct over the Delaware River
         er the technology for the production of   Seguin related to the Tournon Bridge.   in  Pennsylvania,  which  was  his  first
         ropes  was  developed  in  England.  An-  In 1831, he decided to move to the US   new work.
         drew Smith and Robert S. Newall were   to create  a farmland community in
         the main contributors to these techno-  the area of Pittsburgh,  Pennsylvania,   BACK TO FRANCE DURING
         logical improvements, and they were at   at a place that he named Saxonburg.   THE GOLDEN AGE OF THE
         the origin of the invention of closing ma-  Soon he had to take a position as civil   FRENCH ENGINEERS OF
         chines for the fabrication of ropes. They   engineer for the state of Pennsylvania   SUSPENSION BRIDGES
         competed all the time, claiming credit   because the income from the farm was   In France during that time, the con-
         for the inventions. In the 1840s Newall   not sufficient. He took part in the con-  struction of suspension bridges was
         introduced an iron wire rope made of 6   struction of canals and railways.  hugely popular. A lot of companies be-
         strands with 19 wires wrapped around   John August Roebling, who was obvi-  gan constructing them. The wire rope
                                                                               was fabricated on the ground close to
                                                                               the bridge. It was made  of a bundle
                                                                               of parallel wires which were then en-
                                                                               closed by a system of ligature in order
                                                                               to keep a round section. When installed
                                                                               on the top of the piles, the cable took a
                                                                               parabolic shape. The wires were slid in
                                                                               between in order to adjust their length
                                                                               (wires located in the inner radius were
                                                                               too long and those located on the outer
                                                                               radius were  too short),  but these dis-
                                                                               placements were restrained by the
                                                                               ligature presented above. Ensuring a
                                                                               balanced distribution of the line pull in
                                                                               each wire was very difficult.
                                                                                 A large number of bridges were built.
                                                                               Unfortunately, the quality  as well as
                                                                               the accuracy of the fabrication was
                                                                               not suitable for the challenges of such
                                                                               works,  especially regarding the fabri-
           This article was one of the last pieces of literature penned by Donald Sayenga before his   cation of the cables.
           passing in February 2019. When Don met somebody in France, passionate for the same   The administration of Ponts et
           subject, fruitful exchanges made possible the clarity on many points of the history of rope.
                                                                                                continued on page 20
         18     Wire Rope News & Sling Technology   October 2019
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