Fig. 3 (above): Charles C. Sunderland, left, at his retirement from the Roebling Company after more than 50 years of service in 1952, with Ferdinand W. Roebling III, great grandson of Company founder and Brooklyn Bridge
designer John A. Roebling. Trenton Public Library.
Fig. 4 (above): Charles G. Roebling, the third son of John A. Roebling, President of the John A. Roebling’s Sons Company from 1976-1918, patented a 37-wire strand in 1915 similar
to the strands on the GWB suspender ropes. Hamilton Schuyler.
Fig. 5 (right): The 2 7/8 inch, 6 x 37 GWB suspender ropes have a 6 x 7 independent wire rope center, and contain
ten different sizes of wire. Engineering News-Record, 1931.
at the Golden Gate create a more corrosive environment than we have on the Hudson River. We’ve also maintained our ropes to a high level to get a little more life out of them.” For the original suspender ropes, Charles Sunderland (Fig. 3), the Roebling
Company’s Chief Bridge Engineer, specified a 6 x 37 configuration with an independent wire rope center to maximize their service on the bridge. Sunderland joined the Roebling Company in 1901 and worked under Charles G. Roebling (Fig. 4), the third son of John A. Roebling, the designer of the Brooklyn Bridge and the founder of the family wire rope business. Charles Roebling graduated from Rensselaer Polytechnic in 1871 and served as the president of the family business from 1876 until his death in 1918.
“This is a structural
engineer’s dream.” - Andrea Giorgi Bocker, GWB Resident Engineer
According to Donald Sayenga, an historian and a former sales executive at
Bethlehem Steel’s wire rope division, John A. Roebling “achieved the first American advancement in wire rope theory” in the late 1840s. “Realizing that the defects of six-strand ropes could be corrected by combining wires of different diameters in the strands, he devised a three-size construction that is now known as Warrington construction. By starting with a seven-wire strand made of one wire size, Roebling added an outer layer of 12 wires of two different alternating sizes,” in order to improve roundness and to decrease hollow space within the strand.
26 JULY-AUGUST 2012 WIRE ROPE EXCHANGE
Fig. 7: Roebling workers preparing the first four 3,500 ft. long, 2 7/8 inch Roebling ropes for crossing the Hudson to support the footbridges for building the GWB’s main cables, 1929. Smithsonian.
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