John A. Roebling: A Bicentennial Celebration of His Birth 1806-2006

Greetings: Welcome to Brooklyn and Manhattan, both ends of the Brooklyn Bridge, designed by John Augustus Roebling, who we honor today. I shall not reiterate material, nor infringe upon subsequent speakers and papers that will indeed elaborate and detail the background and construction of this most famous, notorious, and celebrated landmark of our premier city in the world. My sole reason for this brief preamble is to record an event that possibly may fall through the small seams in the storied-fabric of the Brooklyn Bridge's colorful history, well documented by David Mc Cullough in his popular book. Recognizing those facts the American Society of Civil Engineers designated the Brooklyn Bridge as a National Historic Civil Engineering Landmark in 1972, entitling it to a bronze plaque to mark the occasion. The award was mounted on the west face of the East Tower, unveiled with due ceremony jointly by the City of New York and the Metropolitan Section ASCE. That event entailed convening at City Hall, marching informally over the bridge to the East Tower, where the unveiling occurred. A sizeable crowd of citizens on hand witnessed the happening, which was also televised by news anchor Gabe Pressman. The entourage consisted of N.Y.C. Mayor John V. Lindsay and City Public Works Officials, M.D. Morris P.E., President of the Metropolitan Section, ASCE, Michael Salgo representing ASCE, H.Q., along with many other city and ASCE dignitaries. The event was a happy Sunday worth noting.

The biographical sketch about the young Roebling in Germany will ask the question about the foundations for his later pioneering achievements in US. His.first step in engineering education was to attend Unger's school in Erfurt. In 1824 he went to Berlin to continuous his engineering studies. Roebling was one of the first students to listen to the new lectures on bridge design at the Building Academy. He started his practical work as a construction supervisor in Westphalia. In 1828 he designed first suspension bridges and was preparing for the exam in construction. In 1830 he founded an emigration society together with Etzler. Without passing his second exam he went to U.S. in 1831. In Pennsylvania Roebling had not only his own career in mind; he was also looking for a place where a community could earn its livelihood in agriculture but at the same time had the potential for industrial development. After all, Roebling's knowledge and experience secured him finding his place as an engineer.

John A. Roebling designed some of the longest and most well-known suspension bridges of the 19th century. Roebling developed a hybrid suspension bridge form, combining a suspension cable with inclined stays and a stiffening truss. Roebling's technical writings reveal his skills as an engineer—proficient with theory, but able to draw on experience and observation. Roebling relied on approximate design methods and possessed a deep understanding of structural behavior. Roebling's suspension bridges pushed the limits of the 19th century bridge design, and they inspired the development of more exact structural analysis methods. Roebling's stayed suspension bridge system represents an extremely safe and economical system for long span bridges. Although rarely built after Roebling's career, variations of the stayed suspension bridge continue to be proposed for very long spans.

Roebling became acquainted with Navier's theory at the Berlin Bauakademie in 1824/25. During his road planning work in Westphalia, he developed several suspension bridge projects in 1828. Roebling's travels along the Rhein and Ruhr in the winter of 1828 were connected with these projects. Roebling supplemented his notes on Dietlein's bridge-building lectures at the Berlin Bauakademie with excerpts from newer literature on suspension bridges. Under the title "Remarks on Bridge Construction" he discussed the results of his studies. Four known bridge projects can be distinguished. Two are only elaborated as an idea, in one case the project is only known by official letters. Only in the case of the Freienohl Bridge is there an exact description of the project. None of them have been brought to realization. Security considerations of the Berlin Oberbaudeputation probably led to the decision not to execute Roebling's Finnentrop project. This decision ought to be understood within the context of a bridge collapse in Nienburg /Saale in December 1825. When Roebling immigrated to the United States, he used his knowledge in construction methods and experiences with an experimental approach. For this reason, it is interesting to compare the early German projects with his first American bridges. While Roebling's first canal aqueducts combined suspension bridges with trusses, the Niagara Bridge marks a radical step forward to another dimension and to a new approach that emphasized thinking in terms of "systems". Interestingly, he also consistently maintained his construction principle for attaining stability by using rigid, wrapped main cables, inclined stays and wooden trusswork. Although he later used wrought iron profiles, he continued to use wooden constructions in his basic plans for a long time. There is no evidence that he made any contribution to the theories of trusses in a manner comparable with Whipple, Culmann, Gerber or others. Roebling's special talent lay in his constructive gifts.

John A. Roebling's accomplishments as an innovative and talented engineer and contractor culminated in the completion of several notable wire cable suspension bridges including the Niagara Gorge railroad bridge, the Cincinnati - Covington Bridge, and the Brooklyn Bridge. Roebling's success in designing wire cable suspension bridges resulted from his initial experiments with wire rope making and use on several projects in western Pennsylvania. The first successful use of Roebling's wire rope was in 1842 to replace hemp ropes on incline No. 3 on the Allegheny Portage Railroad near Johnstown. Subsequent projects in Pittsburgh included a suspension aqueduct across the Allegheny River (1845) and a suspension bridge across the Monongahela River (1846). Roebling's success with wire rope in western Pennsylvania established his reputation leading to increased demand for and use of wire rope on other projects. To establish a competitive edge and facilitate growth, Roebling relocated his wire manufacturing to Trenton, NJ in 1849, where his enterprises flourished for generations.

For centuries, wood and stone had been the principal materials used in bridge construction, but from the time of Abraham Darby's Iron Bridge, cast iron, then wrought iron and thereafter steel became increasingly used as construction materials. Although the use of these new materials in lightly trafficked "road" bridges was successful, the railway age was to signal the necessity for stronger bridges to withstand much heavier loads. These problems became acute as railroads spread and engineers started to consider how to construct railway bridges with spans of several hundred feet. Initially two different methodologies were used by two of the most brilliant engineers of the age. John A. Roebling's choice of design was the suspension bridge and his Niagara Bridge is compared with the tubular bridges constructed by Robert Stephenson in the United Kingdom and Canada. Later developments led to other solutions but these two methodologies provide us with a classic study of the state of the art of the Civil Engineering profession at that time.

The four East River Bridges connect the boroughs of Manhattan, Brooklyn, and Queens. Built within 4 miles and 25 years of each other, the older bridges, particularly the Brooklyn Bridge, have inspired the design of the younger bridges. This is most of all true for the youngest of the four, the Manhattan Bridge. Despite the important role the bridges play in the city's connectivity, they were allowed to slip into disrepair during the mid-20^th century. This has led to a billion dollar rehabilitation of the four bridges, carefully staged over the past two decades to allow for continuous connections between the city's boroughs.

David McCullough's popular account of The Great Bridge begins: "A bridge over the East River...had been talked about for nearly as long as anyone could recall." Indeed, the epic story of building the Brooklyn Bridge began before the first caisson was sunk or even the first line surveys. The story of planning the bridge—the private correspondence, political debates, business deals, technological innovations, design proposals—is fascinating in its own right. It serves to highlight several of the facets of John A. Roebling's genius, and is instructive for its parallels with project planning today. Though "public involvement" was not a legal responsibility for 19^th century engineers, general readers had ample opportunity to be aware of engineering principles and engineers in society. Newspaper articles of the time contain a remarkable level of engineering detail, down to the design strength of specific bridge members, and they note the ASCE's prominent position in technical review of projects. The successful engineer assumed the broad role of planner and marketer as well as technical expert. Much of the background on planning for the East River Bridge resides in the designer's own history, his confidence in his craft and facility in communicating that craft to the financiers and opinion makers of the day. Roebling's 1867 Report to the President and Directors of the New York Bridge Company is a model project proposal. As with any typical proposal, it summarizes the major planning considerations and engineering features, among them accommodating projected traffic, impacting the least amount of valuable property, and designing the structure to withstand all foreseeable loads. Yet, infused in each technical discussion are a new idea to generate enthusiasm for the possibilities of the project and a strong source of assurance for building the structure in Roebling's way. In this essay I outline the context of the decision to build this particular bridge in this particular place, sketch the vital role that the engineer played in that decision, and propose ways in which these historic events and processes may inform engineers and planners in our time and place.

Francis Collingwood was born in Elmira, NY in 1834. He graduated with a degree of Civil Engineer in 1855. He worked in his family jewelry business and performed many short term engineering assignments between 1855 and 1869. From 1869–83 he worked under Washington A. Roebling as Assistant Engineer for construction of Brooklyn Bridge. His tasks included caisson sinking and fitting, building of towers, anchorages, and New York approach and Station. He also designed arches under the New York approach. In 1883, he was sent by Roebling to perform inspection of and repairs to Allegheny Suspension Bridge. In 1885, he became a regular contributor to "The Sanitary Engineer", and a Consulting Engineer. He designed the largest drydock in the U.S. at Newport News, VA which was opened in 1889. His diversified interests included concrete, fire and flood protection, beach erosion, dam safety, masonry, road building, forest preservation, and foundations and caissons. In 1898, when bottom chords of stiffening trusses of Brooklyn Bridge buckled, Collingwood published a detailed report to calm the fears of the public and press about its safety. He established and endowed the Collingwood Prize in 1894 for junior members of ASCE. He wrote about 100 papers, reports, discussions, and speeches. For his paper on Repairs to the Allegheny Bridge, he was awarded the Telford Medal by Britain's Institution of Civil Engineers. He died at Avon, NJ in 1911.

Around 1892, John A. Roebling's Sons Co. introduced one of the first concrete fireproof floor systems to be used in the United States. The floor was designed to span between I-beams in steel-frame buildings. Made with stiffened wire-cloth manufactured by a Roebling's Sons Co. subsidiary, it was marketed as a lighter, cheaper alternative to terra cotta tile and brick arches. New York City's building code required tall buildings to be fireproof; however, the code in the 1890s did not allow concrete floors, and this hobbled the firm's floor business there. In the early twentieth century, after much political intrigue, the code was revised to allow concrete floors, and a great variety of concrete systems came on the market. For a short time the Roebling firm was the main contractor for concrete floors in the United States, and its floors proved their worth in several disastrous building fires and urban conflagrations. But eventually the business succumbed to competition and closed in 1914. Nevertheless, many buildings with Roebling floors are still standing.

One of the most important and least heralded new methods for the construction of steel wire catenary suspension bridge cables was devised by John A. Roebling's Sons' Company of Trenton NJ in the 1920s. The concept of "preliminary straining" has been cited as one of the twenty most significant advances in suspension bridges up to that time. An enormous machine created for the purpose was installed at the company's Kinkora NJ steel mill, setting the stage for the firm's later role as a technological leader in prestressed steel tension members. This paper illuminates the basic concept of the Kinkora Prestretcher, summarizes its history, and describes its present condition.

This paper traces the mid 19^th century John A. Roebling proposals for a bridge across the East River that preceded actual construction of the remarkable Brooklyn Bridge. The East River separated two of the fastest growing cities in the United States with the only means of crossing by ferries, originally rope and later steam powered. Many leading engineers of the time made serious proposals to create a bridge that would be crossable in all seasons and promote trade and transit between Manhattan and Brooklyn, but it remained for the Roebling's to actually build one. The 1864 bridge proposal by Julius Adams is described to put Roebling's proposal in perspective.

Starting in 1851 John A. Roebling became involved in the design and construction of a suspension bridge for railroad traffic over the Kentucky River between Lexington and Danville Kentucky. After many plans and modifications he began construction of the bridge in 1853. After the completion of the anchorages and towers, with the wire for the cables on site, work was stopped in 1855. In 1873 proposals were requested by the Cincinnati Southern Railroad for a bridge at the site. The Roebling Company submitted a proposal to complete their bridge but a proposal by C. Shaler Smith for an iron cantilever bridge was accepted by the railroad. This paper traces the involvement of Roebling and his company in the bridge over a 23-year period and how conditions and changes in material availability plus his experience in building the Niagara Bridge impacted his design.