Engineers of Dreams: Great Bridge Builders and the Spanning of America

by Henry Petroski

  Among the things Ammann had done during the year was to write to Governor Silzer, with a copy to Samuel Rae, who was not only president of the Pennsylvania Railroad but also associated with the North River Bridge Company. In his letter, after stating that he had “no desire to discredit Mr. Lindenthal,” Ammann gave his views on the “scope of plan and size” of the 57th Street Bridge:

  It is over a year ago that I began to suggest to Mr. Lindenthal reduction of the stupendous scope of the plan and also of the size of the bridge. Not having succeeded to convince him and having noticed the discouraging effect of his policy upon the supporters of the project I wrote him a memorandum on May 21, 1923.…

  As regards the size or capacity of the bridge proper it is generally recognized that even for a light bridge a width of 1/20 of the span gives ample lateral rigidity. That would mean 160 feet for the Hudson River Bridge as against the 235 feet now provided for. But in such a long span with a deadweight of more than 50 times the probable greatest wind pressure even a smaller width would give ample rigidity.

  The width is therefore determined by traffic requirements alone. The plan now provides for 20 lanes of vehicles and 2–15 ft. promenades on the upper deck and for 12 tracks on the lower one. A roadway capacity of only 12 lanes of vehicles would provide for a possible traffic of 50 million vehicles per year, which is equal to twice the traffic now crossing the four East River Bridges and is much more than should at any time be concentrated at one point even with ample capacity of approaches.…

  Such arguments regarding the interrelated issues of structural rigidity, traffic capacity, and cost vis-à-vis the width of roadway would have profound implications for the very near future of bridge building, but for the moment Ammann’s objectives were less general. He argued that it would probably be ten to twelve years before Lindenthal’s 57th Street Bridge could be completed, and that in the meantime traffic congestion was becoming “calamitous,” especially in the upper part of Manhattan. He also pointed out that “tunnel advocates” appeared to be gaining ground because Lindenthal’s proposal tipped the economic argument in their favor. Ammann felt the only way to keep further tunnel projects from being pushed forward “by popular demand” was to build a vehicular bridge at 179th Street. He had not told Lindenthal of this specific new proposal of his, as he made clear in the final paragraph of his letter to Silzer: “At the opportune moment I shall lay this proposition before Mr. Lindenthal and I trust that in case he agrees to take it up, it will also have your sanction and support. I shall not mention to him that I laid these matters before you.”

  Later in the year, the Port Authority, which had rejected Lindenthal’s grand bridge plan, scheduled public hearings on building further tunnels beneath the Hudson. Governor Silzer was able to broaden the agenda to include the question of bridges as well. In the meantime, Ammann had come up with a proposal for a bridge at 179th Street that would cost only $30 million, just as Hodge had estimated a decade earlier for a remarkably similar bridge to be located farther down the river. The cost of Ammann’s bridge could be reduced even further, to $25 million, if only vehicle traffic were carried. This proposal was certainly competitive with a tunnel, and Ammann even supported the Port Authority as the natural agency to build such a structure. He also suggested that they might need an expert bridge engineer, and that he would be happy to assume this position. Whereas Ammann may have painted a dark picture when writing to his mother, within a few days Silzer had forwarded Ammann’s analysis of the problem to the Port Authority and issued a press release announcing what he had done. Lindenthal was to learn of these developments in the newspaper, and he penned his reaction to Silzer:

  Othmar Ammann’s 1923 proposal for a bridge across the Hudson River at 179th Street (photo credit 5.7)

  A bridge at Fort Lee of the kind described by [Ammann], cannot be built for $25,000,000. The estimate is far too low. It is the same old way to mislead the public either from design or from ignorance, just as the estimate of Gen. Goethals of $10,000,000 for the vehicular tunnel, which when fully completed will now cost $45,000,000. The public cannot judge of such vagaries in estimates of which engineers are constantly guilty.

  Mr. A. had been my trusted assistant and friend for ten years, trained up in my office and acquainted with all my papers and methods. But I know his limitations. He never was necessary or indispensible [sic] to me. Many other assistant engineers are very able and glad to fill his position. But one does not like to make changes and train up new men as long as it is not necessary.

  Now it appears that A. used his position of trust, the knowledge acquired in my service and the data and records in my office, to compete with me in plans for a bridge over the Hudson and to discredit my work on which I had employed him. He does not seem to see that his action is unethical and dishonorable.

  In spite of Lindenthal’s protests, the practicality of Ammann’s plan attracted immediate interest. A sketch of his suspension bridge with a thirty-four-hundred-foot main span appeared in the first issue of Engineering News-Record for 1924, but there was no protracted discussion of what to many may have looked like just another engineer’s dream. However, in April 1925, that same magazine reported that, “almost unnoticed, the first step has been taken toward the ultimate construction of a bridge so far beyond any existing structure in its size as to rank virtually in a new order of magnitude.” The occasion for the story was that the legislatures of New York and New Jersey had “appropriated a total of several hundred thousand dollars for the preliminary studies.” After he submitted Ammann’s plan to the Port Authority, Silzer had suggested that the agency might want to engage “such a man as Mr. Ammann, who is thoroughly skilled in this kind of work,” but that was not to be for some time.

  When the Port of New York Authority was formed in 1921, Benjamin F. Cresson, Jr., had been appointed its first chief engineer. Cresson was born in Philadelphia in 1873 and was educated at Lehigh University and the University of Pennsylvania. His early career was with the Lehigh Valley Railroad, but he soon joined Jacobs & Davies to work on plans for an East River railroad tunnel and on the first McAdoo tunnels under the Hudson. He had a well-established reputation in tunnel and harbor work when he was named chief engineer of the Port Authority. In that position, he would have had considerable influence on the nature of Hudson River crossings had he not died suddenly in early 1923 following an operation for appendicitis. The office of chief engineer was not filled until late September, by William W. Drinker, who had extensive harbor and terminal experience but was not a bridge engineer, which was what the Port Authority would soon need.

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  The 179th Street project was not the only bridge under consideration by the Port Authority. Since colonial days, travelers between New York and Philadelphia had passed through Bayonne, New Jersey, and Staten Island, using ferries to cross the Kill van Kull and the Arthur Kill, the bodies of water that separated Staten Island from the Jersey mainland, and whose designations derived from the Dutch word kil, meaning “channel” or “creek.” First oar-propelled scows, then horse boats (whose side wheels were powered by horses on a treadmill), then steam ferryboats served the purpose, but with the growth of population and the attendant vehicle traffic in the 1920s, there were growing calls for bridges. The Port Authority came under some criticism for worrying about automobile traffic instead of the harbor-goods traffic that was said to be its principal charge; by 1924, legislation had been passed enabling the Authority to plan bridges. It did so, between Bayonne, which was at the bottom of a New Jersey peninsula approaching the north shore of Staten Island, and the towns of Elizabeth and Perth Amboy, which are across the kill that forms the western boundary of Staten Island and contains the New York-New Jersey state line. These were the same sites identified by Boller & Hodge years earlier, but it took time for politics and need to catch up with the vision of that engineering firm.

  Two bridges across Arthur Kill were authorized first, and, in conjunction with the design of these struct
ures, Silzer had written in a letter of support in May that “the Port Authority ought to avail itself of the services of O. H. Ammann,” whom he understood to be available “just at the moment.” In fact, by early November 1924, Ammann had actually submitted to the Port Authority a bid for preparing plans for the Arthur Kill bridges and was “anxiously awaiting their decision.” While he was waiting, on November 7, chief engineer Drinker sent a letter to “four or five prominent bridge engineers experienced in the planning of large bridges.” After describing the conditions the bridges had to meet, Drinker wrote for the Port Authority: “We desire to secure the services of a bridge engineer and wish you to make a proposal for carrying on the work.” Ammann’s reputation seems not to have been sufficiently established for the young Port Authority, which was trying to establish its own reputation. Thus the task, which clearly involved more than bridge engineering, went to J. A. L. Waddell, whose fifty-year career was older than Ammann himself, and whose bearing and bemedaled appearance may have counted for as much in the politically charged circumstances as his expertise.

  Since the Port Authority had to raise the construction cost of the bridges by bond issues backed by the earning power of the bridges themselves, “it was necessary that the bridges be planned by an engineer of recognized standing, to assure the confidence of prospective bond buyers, although only a small sum was available as compensation for this engineer.” This was the situation, at least, as interpreted by Engineering News-Record, which called the announcement of the choice of Waddell, and the revelation of how it was made, “an unpleasant shock … to established views of the relation between the engineer and his client.” Drinker’s letter was described as follows:

  It calls for bids on price and time of delivery of expert engineering services—services involving a very high type of specialized engineering skill and trained judgment—in precisely the way that one would ask for price and time of delivery on a ton of coal or a thousand of brick. For the first time, thus, a responsible and well informed public authority has resorted to the bidding system of selecting a professional man to direct the expenditure of large sums of public money.…

  We doubt whether the Port Authority would think of defending a lawsuit on which its existence depends, or in which $10,000,000 is at stake, through counsel retained as the result of competitive bidding.

  Though the journal admitted that competitive bidding for the services of engineers had increasingly been taking place in small communities, whose local staff not only was not qualified to carry out the work but also could not judge the qualifications of available engineers, the writer felt there was no excuse in the case of the Port Authority, which had “able and widely informed engineers on its staff.” Yet the selection of Waddell remained, as did his designs for the two bridges, which were almost identical high-level cantilevers: the more southerly one, at Perth Amboy, was to have a main span of 750 feet and an overall length of over ten thousand feet; the main span of the bridge at Elizabeth was to be 672 feet. Even if undistinguished, especially in comparison with such cantilevers as the Firth of Forth, the Quebec, and the Queensboro, both bridges were major engineering projects, and Waddell could not do the work alone. Among those who also worked on the designs were William Burr and George Goethals. Ironically, however, Othmar Ammann is commonly misidentified as the designer of these bridges over the Arthur Kill, because of subsequent developments.

  Ammann became associated with the Staten Island bridges when he was appointed bridge engineer for the Port Authority on July 1, 1925. Silzer had persisted in writing to officials of the Authority that Ammann had had a great deal to do with getting the 179th Street bridge project as far as it was, which in March 1925 meant that both states had passed legislation authorizing the Port Authority to build a bridge at the location. Shortly after that, and after an “encouraging interview” with Drinker, which took place at Silzer’s suggestion, Ammann was hired to add some bridge-building experience to the staff. Although by that time an outside contract had already been let for the Staten Island bridges, in his new position Ammann oversaw their design and construction. The two bridges were completed six months ahead of schedule, and opening ceremonies took place simultaneously, on the same day in June 1928. The southern bridge was named Outerbridge Crossing—not because of its remote location but after Staten Island resident Eugenius H. Outerbridge, the first chairman of the Port Authority, who was guest of honor at the opening ceremonies. The other structure was to be named the Arthur Kill Bridge, but when General Goethals, the first chief engineer of the Port Authority, died shortly before its dedication, it was named the Goethals Bridge, thus making it, like the tunnel named for his critic Holland, one of the few civil structures named for an engineer.

  The other bridge between Staten Island and New Jersey, across the Kill van Kull, was truly to be Ammann’s design. There was to be a distinguished group of consulting engineers, including William Burr, Daniel E. Moran, Leon Moisseiff (as advisory engineer of design), and Joseph B. Strauss, who was at the time trying to generate support on the West Coast for his suspension bridge across the Golden Gate. For all the highly visible consultants, Ammann’s experience with the Hell Gate Bridge had actually prepared him well to design, with assistant E. W. Stearns and engineer of design Allston Dana, a steel arch that would be two-thirds longer than the Hell Gate and, at 1,675 feet, actually the longest in the world, surpassing by five feet the span of the Sydney Harbour Bridge, then under construction in Australia. (Ammann’s arch would in fact not be surpassed until 1977, and then only by twenty-five feet, when the New River Gorge Bridge, at Fayetteville, West Virginia, was completed.)

  The Sydney Harbour Bridge, known affectionately to some as “the coat-hanger,” might have been a steel cantilever had not John Bradfield, chief engineer of the Public Works Department of New South Wales, visited America during its design. “Lindenthal’s departure from the usual stark steel arch so impressed” him at Hell Gate that Bradfield quite consciously modeled the Sydney Harbour Bridge after it, but with some deliberate distinctions. Whereas Lindenthal’s Hell Gate had an odd number of panels, so that a redundant diagonal member was necessary for symmetry and forms a steel X to mark the center of the arch, the Sydney Harbour Bridge was designed with an even number of panels, so that there is a more subtle visual transition between the two halves of the main structural element. As if to distinguish himself from his mentor’s masterpiece, Ammann chose to give the Kill van Kull arch also an even number of panels. The Sydney Harbour arch, for which David Steinman served as a consultant, was built with another sharp distinction from the Hell Gate, the termination of whose top chord had been criticized for being continued visually into the masonry pylons. The steel of the top chord of the Australian arch ends abruptly some distance from the stone, emphasizing the true structural action of the arch’s springing from the bottom chord.

  The meeting of steel and stone in architect Cass Gilbert’s early architectural drawings of Ammann’s design for the Bayonne arch was actually somewhat ambiguous, but the question became moot when the steel framework at the ends of the arch was not encased in masonry as originally planned. Though the Kill van Kull bridge was dedicated as the Bayonne Bridge less than a month after the bridge across the Hudson at 179th Street, the details of the design and construction of the world’s longest steel arch would forever be overshadowed by the contemporaneous design and construction of the great suspension bridge at 179th Street.

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  After the necessary legislation for a Hudson River bridge had been passed, only one great nontechnical obstacle to the four-decade-long struggle remained. Bonds had to be sold, of course, and when it was announced in December 1926 that $20 million was underwritten by National City Bank, Engineering News-Record reported on “the high regard of the banking world for the essential integrity of that unique body,” the Port Authority, which alone was responsible for the security of the debt. Even as the journal was praising the fiscal reputation of the Authority, however, it
commented on the body’s “metamorphosis” from a facilitator of freight handling in the port, which was its raison d’être, to an aggressive bridge builder. The trade journal concluded that “the Port Authority would do well not to delude itself into believing that building bridges was its job,” but that would indeed appear to be the major activity during the next five years or so for Ammann and his engineering staff.

  Cantilever design originally accepted for the bridge over Sydney Harbour (photo credit 5.8)

  Early in 1927, five papers dealing with the suspension bridge at 179th Street were read before a local meeting of the American Society of Civil Engineers. Four were presented by Port Authority engineers: one by Ammann, who gave an overview of the project; one by Dana, who described some of the calculations involved in the structural design; and one each on surveying procedures and on traffic studies. A fifth paper, however, was presented by R. S. Buck, who “challenged the design as to a number of its major features, and called for a thorough reconsideration and restudy of the project.” Buck may at first have appeared to have been in the long tradition of naysayers who oppose projects that go beyond state-of-the-art experience—as Ammann’s certainly appeared to, even if that was being denied—but Buck’s criticism was more reasoned than grudging. He suggested that a sense of urgency to get the bonds sold and the contracts let may have led to overconfidence, and spoke to the value of looking at competitive designs. His criticism focused on some specific points, including the question of wire cables versus chains, which was still open at the time, recalling the controversy that accompanied the design of the Manhattan Bridge. His final point related to the design of the towers; these were proposed to be steel-framed for the first stage of construction, which was to include only a single deck for vehicles, then later, when a second deck carrying light rail traffic would be added, to be encased in concrete and faced with stone. In Buck’s opinion, such “pseudo masonry is out of place both esthetically and structurally.” Only the “lateness of the hour” curtailed discussion of such matters, but they were not to lie buried in the minutes of an engineering meeting. As with large projects generally, early plans would be modified and solidified as design and construction progressed.