Editing John A. Roebling (section)

==Career==
[[File:Brooklyn Bridge by David Shankbone.jpg|thumb|The [[Brooklyn Bridge]] in February 2007]]
[[File:Roebling Shop with bridge.jpg|thumb|Roebling's Shop in [[Saxonburg, Pennsylvania]], adjacent to a replica of the Brooklyn Bridge]]
[[File:Cincinnati-roebling-suspension-bridge.jpg|thumb|[[John A. Roebling Suspension Bridge]], spanning the [[Ohio River]] from [[Cincinnati]] to [[Covington, Kentucky]], at night]]
On May 22, 1831, Roebling left Prussia with a group of emigrants bound for the United States. They included his brother Carl and the older [[Johann Adolphus Etzler]], who believed in a technological [[utopia]]. Engineers had difficulty advancing and achieving economic mobility in Prussian society, in part because of the [[Napoleonic Wars]], which had lasted until 1815, and suppressed investment in infrastructure. During this period, [[Prussia]] also had considerable political unrest, as authoritarian governments took the places of democratic ones.

Etzler believed that they could create a technological utopia in the United States, but disputes arose among the men en route. The group split up after reaching [[Pennsylvania]]. John and Carl Roebling purchased 1,582 acres (640 hectares) of land on October 28, 1831, in [[Butler County, Pennsylvania|Butler County]]<ref>''Historic Saxonburg and Its Neighbors'', Ralph Goldinger, {{ISBN|1-55856-043-2}}</ref> with the intent to establish a German settlement, to be called [[Saxonburg, Pennsylvania|Saxonburg]]. Most of the other settlers had remained with Etzler.  In 20th-century recognition of his historic importance, the [[John Roebling House]] at Saxonburg was listed on the [[National Register of Historic Places]] in 1976.<ref name="nris">{{NRISref|version=2010a}}</ref>

When the Roeblings and others arrived, the United States was in the later stages of an economic boom, which ended in the financial [[Panic of 1837]], reducing everyone's opportunities. Farmers were deeply affected by it as they often depended on credit to produce the next season's crops. But by the 1840s, the economy was improving and many Americans believed in the nation's [[manifest destiny]] to extend its borders and achieve greatness on the North American continent. Transportation between eastern industrial hubs and frontier farming markets had become a matter of both national and popular interest.

Many railway and transportation projects were under way near the site which Roebling chose for his colony, but instead of continuing in the engineering profession, he took up farming.  After five years he married Johanna Herting, a tailor's daughter. He found agrarian work unsatisfying, and Saxonburg  attracted few settlers.

In 1837, after the birth of his first child and the death of his brother Carl, Roebling returned to engineering for work. He first worked on projects to improve river navigation and build [[canal]]s. For three years, he conducted surveys for the state of [[Pennsylvania]] for railway lines across the [[Allegheny Mountains]], from the capital, [[Harrisburg, Pennsylvania|Harrisburg]], to [[Pittsburgh]] in the far west, at the start of the [[Ohio River]].

In 1840, Roebling wrote to [[suspension bridge]] designer [[Charles Ellet Jr.]], offering to help with the design of a bridge near [[Philadelphia]]:<ref>Steinman, David B. & Watson, Sara Ruth, ''Bridges and their Builders'', 1941</ref>
<blockquote>The study of suspension bridges formed for the last few years of my residence in Europe my favourite occupation ... Let but a single bridge of the kind be put up in Philadelphia, exhibiting all the beautiful forms of the system to full advantage, and it needs no prophecy to foretell the effect which the novel and useful features will produce upon the intelligent minds of the Americans.</blockquote>

At that time, canal boats from Philadelphia were transported over the Allegheny Mountains on railroad cars in order to access waterways on the other side of the mountains, so that the boats could continue to Pittsburgh. The system of inclines and levels that moved the boats and conventional railroad cars was a state-owned enterprise, the [[Allegheny Portage Railroad]]. The railroad cars were pulled up and down the inclines by a long loop of thick [[hemp]] rope, up to 7&nbsp;centimetres thick. The hemp ropes were expensive and had to be replaced frequently.

Roebling remembered an article he had read about [[wire rope]]. Soon after, he started developing a seven-strand wire rope at a [[ropewalk]] that he built on his farm. In 1841, Roebling began producing wire rope at Saxonburg to use in suspension bridges and such projects as the portage railroad.

In 1844 Roebling won a bid to replace the wooden canal [[aqueduct (bridge)|aqueduct]] across the [[Allegheny River]] with the [[Allegheny Aqueduct (Pittsburgh)|Allegheny Aqueduct]]. His design encompassed seven spans of 163 feet (50 m), each consisting of a wooden trunk to hold the water, supported by a continuous cable made of many parallel wires, wrapped tightly together, on each side of the trunk. He followed this innovation in 1845 by building a [[suspension bridge]] over the [[Monongahela River]] at Pittsburgh.  The confluence of the Allegheny and [[Monongahela River|Monongahela]] rivers at [[Pittsburgh]] forms the [[Ohio River]].

In 1848, Roebling undertook the construction of four suspension aqueducts on the [[Delaware and Hudson Canal]]. During this period, he moved to [[Trenton, New Jersey]]. In Trenton, Roebling built [[John A. Roebling's Sons Company, Trenton N.J., Block 3|a large industrial complex]] for wire production for his growing company: John A. Roebling's Sons Company. This complex inspired Trenton's motto that appears on the [[Lower Trenton Bridge]]: "Trenton Makes, the World Takes".

Roebling's next project, starting in 1851, was [[Niagara Falls Suspension Bridge|a railroad bridge]] connecting the [[New York Central]] and [[Great Western Railway (Ontario)|Great Western Railway]] of Ontario, Canada over the [[Niagara River]]. Construction took four years. The bridge, with a [[clear span]] of 825 feet (251 m), was supported by four, ten-inch (25&nbsp;cm) wire cables, and had two levels, one for vehicles and one for rail traffic.

While the Niagara bridge was being built, Roebling designed a railway suspension bridge across the [[Kentucky River]], which required a [[clear span]] of 1,224 feet (373 m). The anchorage and stone towers were completed, and the cable wire delivered along with the material for the superstructure, when the railway company became insolvent. The bridge construction was halted and he was never able to complete it.

What is now known as the [[High Bridge of Kentucky|High Bridge]] was later completed as the first [[cantilever bridge]] in the US, with a [[truss bridge|truss for carrying the railway track]]. A second version was built on the same foundations in 1911. The highest railroad bridge over a navigable river in the United States, the bridge is still in use.

In 1859 Roebling completed [[Sixth Street Bridge (Pittsburgh, Pennsylvania)|another suspension bridge]] at Pittsburgh over the Allegheny River. Its total length was 1,030 feet (314m), consisting of two main spans of 344 feet (105m) each, and two side spans of 171 feet (52m) each. His son [[Washington Roebling]] worked with him on that project, having completed his engineering degree.

The [[American Civil War]] brought a temporary halt to Roebling's work, as resources were diverted to the war effort. In 1863 building resumed on a bridge over the [[Ohio River]] at [[Cincinnati]], which Roebling had started in 1856 and halted due to lack of financing. He finished this bridge in 1867. The Cincinnati-Covington Bridge, later named the [[John A. Roebling Suspension Bridge]] in his honor, was the world's longest suspension bridge, with a main span of 1,057 feet (322 m), at the time it was finished.