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

by Henry Petroski

  Among the first to bring such information to the fore was J. Kip Finch, professor of civil engineering at Columbia, whose article “Wind Failures of Suspension Bridges, or, Evolution and Decay of the Stiffening Truss,” appeared in Engineering News-Record about four months after the collapse. His article concluded with a section headed “The lesson is plain,” and the lesson was: “History, in short, has been repeating itself, although this fact has, apparently, not been known even to engineers who have made a specialty of this type of construction.” After this indictment of ahistorical engineers, Finch concluded optimistically, but perhaps without complete conviction, “This time the problem of preventing undulations in suspension bridges will undoubtedly be solved.” Two weeks later, in a letter to Engineering News-Record, no doubt prompted by letters to it, Finch took pains to assure readers that he had not meant to infer that “the modern bridge engineer … was remiss in not anticipating” what had happened. He argued that it was “unbelievable” that the eight-thousand-ton center span of the Tacoma Narrows Bridge could be lifted by the wind as easily as the 460-ton deck of the Wheeling Suspension Bridge, which had been destroyed in 1854, or that the thirteen-thousand-ton deck of the Bronx-Whitestone or the fifty-six-thousand-ton deck of the George Washington could be compared to the lighter fabrics of old.

  Finch’s own interpretation of history was proved to be a bit questionable when he added that no engineer, so far as he knew, had “recognized in the twistings of some of these earlier failures, a characteristic aerodynamic phenomenon.” Though John Roebling might not have used such terms, he had written as early as 1841 of the problems of bridges in the wind. Indeed, before that, the Scottish engineer J. Scott Russell had written, in the wake of the 1836 collapse of the Brighton Chain Pier (which was in fact a multispan suspension bridge out to sea), about how the wind can set structures like bridge decks into oscillation as surely as a bow does a violin string. An engineer’s knowledge and use of history was a touchy point after the Tacoma Narrows collapse, however, and Finch concluded that “it is asking too much of the human mind to suggest that the engineer should have anticipated the Tacoma failure.” He then articulated what many other engineers were saying and would continue to say about the issue that had been thrust upon them:

  It is also a mistake to assume that failures should never occur. The engineer cannot wait until he knows “all” about a device before he builds it. In general theory follows practice—the theory of heat followed the first use of the steam engine, truss analysis came after the truss, etc.—and there has, as yet, been no substitute developed for experiment—even in science. A history of bridge building which contained no records of failures would be a history almost devoid of progress. Man must ever struggle to bring into being the children of his imagination, for through such creation progress is possible. It is thus inevitable that, in daring to do bigger and better things, there will always be some failures. Failures, in fact, are a sure sign of progress. While a failure is always materially wasteful, it is always a stimulant to increased knowledge. We may rest assured that the engineer will not make the same mistake twice.

  Argue as Finch and others might, engineers had indeed made the same mistake twice, but Finch’s reasoning, questionable though it was, would serve to console engineers who could not bear to be wrong. They could get on with picking up the pieces, turning them around in their hands and their minds, and going on to the next project with more experience and judgment. As for Moisseiff, who had to deal with the collapse of the Tacoma Narrows more directly, engineers by and large must have thought, “There but for the grace of God go I.” Moisseiff continued to work on engineering projects, including plans for the reconstruction of the Brooklyn Bridge and “assisting in the solution of the problem forced upon the profession by the Tacoma Bridge failure,” but his heart may not have been in them—or may have been in them too much.

  Moisseiff died of a heart attack less than three years after the disaster, and neither his obituary in Engineering News-Record nor the unusual number of letters to the editor paying tribute to his memory gave much more than passing mention to the Tacoma Narrows incident. Only a letter from Ammann, who had not merely relied on Moisseiff but also derived a measure of his own reputation for success from the work of the late engineer, even dared address the matter. “The one great disappointment in Mr. Moisseiff’s career,” Ammann wrote, “was the failure of the Tacoma Narrows Bridge, the design of which he had originated and guided.” Yet, Ammann continued, “it would be improper for his fellow professionals to put the blame for that failure entirely upon Mr. Moisseiff’s shoulders,” for “he followed a trend in long span suspension bridge design which appeared justified” at the time. Ammann may well have been speaking of himself. He returned to this theme in the memoir of Moisseiff, which, written with his associate Frederick Lienhard, appeared in the Transactions of the American Society of Civil Engineers in 1946. Moisseiff was called “one of the best informed of engineers,” and his activities at the end of his career were described as those of “a consultant to consulting and executive engineers.” Ammann himself was a consummate example of these latter two categories—no engineer could have accomplished single-handedly what he did in his career.

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  Ammann left the Triborough Bridge Authority in 1939 to go into private practice. In that capacity, he worked on a variety of bridge and other projects, including studies for a suspension bridge across the York River in Virginia and one across the Delaware River at Wilmington, in addition to participating in the Tacoma Narrows investigation. In 1946, when he was already past what in those days was generally considered retirement age, Ammann entered into partnership with Charles S. Whitney, who as an engineering student at Cornell had worked under Ammann during vacation periods, and who had gone on to establish himself in Milwaukee as a specialist in reinforced-concrete structures. Together, they formed the firm of Ammann & Whitney. Since few bridges were being built at the time, the engineering firm worked on projects involving large airfield hangars, long-span buildings, and highways.

  After the war, bridge-planning activity picked up in New York and elsewhere. In 1955, a joint report of the Port of New York Authority and the Triborough Bridge and Tunnel Authority was prompted by “the unprecedented increase in the ownership and use of automobiles, trucks and buses since the end of World War II,” which had “forced accelerated nationwide planning and construction of our arterial highway system.” The main results of the joint study were to recommend for construction: (1) a lower deck on the George Washington Bridge; (2) a suspension bridge between Brooklyn and Staten Island across the water known as the Narrows; and (3) a suspension bridge between Throgs Neck in the Bronx and Little Bay in Queens, across the water variously known as the East River and Long Island Sound. The consulting engineer for these projects, as well as for studies for another Hudson River Bridge, at 125th Street, which was not recommended at the time, was the firm of Ammann & Whitney. Thus Ammann, the partner whose expertise was suspension bridges, was once again to be involved in the kind of work he dreamed about.

  The second deck of the George Washington was, of course, part of Ammann’s original design, and he not only would live to see it realized but would direct work on it himself. The New York Narrows bridge was a project that had been developed in the offices of the Port Authority two decades earlier. In his autobiography, the engineer Clarence Whiting Dunham recalled being asked by Ammann in the summer of 1936 to drop his work on the Lincoln Tunnel, then under construction, “to help him with a special project,” which “was to be kept secret.” This involved “an intensive preliminary study of a suspension bridge across the Narrows.” Working directly and intensively for six weeks with Ammann, Dunham made drawings of the elevation of the bridge and sections showing its proposed construction, along with approaches relative to existing streets. According to Dunham, though city officials liked the plan, federal authorities rejected it because the destruction of the bridge during wartime might bloc
k access to the Brooklyn Navy Yard. The plans were then shelved, only to be dusted off when, in the post-World War II years, air power had diminished the importance of the navy yard. The final bridge design and location were to be remarkably close to those proposed in 1936, but in the meantime another New York project would also occupy Ammann.

  The Throgs Neck Bridge was constructed within sight of the Bronx-Whitestone, which in the wake of the Tacoma Narrows collapse had been slated for the addition of a stiffening truss. Materials shortages during the war delayed that modification work until 1946, at which time Ammann described the retrofitting in an article in Civil Engineering. “While the truss members will undoubtedly detract somewhat from the extreme simplicity of the original design, with its plain shallow girders, they will not be sufficiently conspicuous to mar the graceful appearance,” he wrote, perhaps with not a little disingenuousness. In part for ease of construction, this truss was to be added to the top of the deck, which it was now admitted had “inadequate vertical stiffness,” but the resulting superstructure obstructs a dramatic view of the Manhattan skyline from the bridge’s roadway. In the process of stiffening, the traffic capacity of the bridge was also increased, by eliminating the pedestrian walks on either side of the roadway, thus reducing the possibility that people would feel how flexible the bridge did in fact remain.

  The lines of the eighteen-hundred-foot main span of the Throgs Neck Bridge, to the east, were not to be so sleek as those of the original Bronx-Whitestone. Instead of plate girders, more conventional open trusswork was used to stiffen the wide deck, and the towers were to be rather squat-looking. But this bridge project did not bring Ammann renewed public attention in the early 1960s; that was to come with the opening of the lower deck of the George Washington Bridge.

  Ammann’s original concept for the George Washington was, of course, that it would eventually have light rapid-transit railroad tracks on a lower deck, but travel habits and traffic patterns had changed considerably since the bridge, with its single vehicular deck, was opened in 1931. By the mid-1950s, motor-vehicle registration in the region had more than doubled, to three and a half million, and annual crossings of the Hudson River through the Holland and Lincoln tunnels and over the George Washington Bridge had about quintupled. Almost thirty-five million vehicles were using the bridge alone on an annual basis. Thus, when the second deck of the George Washington Bridge opened in August 1962 for the exclusive use of motor vehicles, it was hailed as a “masterpiece of traffic relief.”

  The ceremonies marking the opening of the lower deck were attended by politicians from both sides of the river, and the formalities were highlighted by the unveiling of a bust of Ammann by Governors Nelson Rockefeller of New York and Richard Hughes of New Jersey. But Ammann, who was remembered by his daughter to be at that time a “small man,” only five feet six inches tall, and a “sandy-haired, slightly frail octogenarian—then 83—who stood as majestically as the giant structures that he had fathered,” was not conspicuously present at the ceremonies. According to the newspaper account, Ammann was not standing with the politicians, and “it took a few minutes to locate the designer who was sitting back in the crowd, to get on with the unveiling.”

  Othmar Ammann at the dedication of his bust at the George Washington Bridge, shaking hands with Governors Richard Hughes of New Jersey and Nelson Rockefeller of New York, with the completed lower deck of the bridge visible in the enlarged photograph in the background (photo credit 5.23)

  The bust of Ammann is now on display in the bus terminal at the foot of the bridge on the Manhattan side, but it is scarcely noticed by the travelers and commuters who pass it each day, and it is never seen from the cars of those who drive back and forth across the bridge. The inscription on the bust reads simply, “O. H. Ammann/Designer/George Washington Bridge.” It is ironic that there is no mention on the pedestal of Ammann’s being an engineer, but perhaps that was his choice. According to his son, Werner Ammann, an engineer himself and then a member of Ammann & Whitney, the shy old man agreed to the public honor only because it would “reflect favorably on the entire engineering profession.” For Ammann to be identified as the engineer of the George Washington Bridge may have seemed arrogant; for him to be designated its designer, conceiver, and dreamer was just stating the obvious.

  When the New York Times editorialized on “Mr. Ammann’s Work of Art,” it acknowledged his insistence that “no one man designed the bridge,” yet went on to admit the public reality: “We shall think of Mr. Ammann, however, every time we look at the George Washington Bridge. He was the dreamer, he was the artist, he was the solid and reliable planner who made this beautiful structure possible and durable.” Yet, as a letter to the editor several days later pointed out, nowhere in the editorial was Ammann identified as what he really was, “one of America’s outstanding engineers.”

  Othmar Ammann was said to insist that “anyone who would take exclusive credit for bridge design” was “an egotist.” It would certainly be even more egotistical to declare oneself the engineer of such a structure, especially to the deliberate exclusion of assistant and design engineers who had done much of the work. Joseph Strauss, without question the driving force behind the Golden Gate Bridge, had done just that to his assistant Charles Ellis, of course, and the statue of chief engineer Strauss that was installed at the bridge plaza must have irked many a subordinate. Though first authorized by the Golden Gate Bridge and Highway District late in 1939, a public expenditure for a bronze statue was successfully challenged by the Taxpayers Defense League, and, like many such a monument, this one was dedicated, in 1941, only after funds were provided by Strauss’s widow.

  The Strauss statue was originally located conspicuously at the toll plaza, atop an ostentatious pedestal, obstructing the view of the bridge itself, according to some. It was subsequently relocated to a less ornate base and less prominent setting, in a small plaza between the bridge’s gift shop and parking lot. In New York, the perhaps overly modest pedestal and bust of Ammann, and its imprecise inscription, soon became so obscure in its location in an urban bus terminal, and forgotten by public and profession alike, that the issue of ego seems long ago to have become moot.

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  The final great bridge design that Ammann was to be credited with was the one he had had Clarence Dunham work on secretly in the summer of 1936. A bridge crossing the Narrows between Brooklyn and Staten Island was proposed as early as 1910 by the New York engineer Charles Worthington. His design consisted of a twenty-five-hundred-foot arch made up of hollow voussoirs of nickel steel that would be erected by a novel method devised by Worthington so that no falsework would obstruct the entrance to the harbor during construction. The proposed arch was to be 260 feet above high water, subject to the approval of the War Department, and the $15-million bridge was expected not only to provide a monumental gateway to New York from Staten Island but also to open up the island to “mercantile development.”

  The arch plan was shelved, and so were many later suspension designs, but by the time Ammann’s bust was unveiled at the George Washington Bridge, his Narrows bridge had long been under construction. Work had begun in earnest in the mid-1950s, and Milton Brumer, its chief engineer, recalled that 125 engineers in the Ammann & Whitney design office were assigned exclusively to the project, and there were another seventy-five field engineers, not to mention the thousands of construction workers: “Every one of them has a good reason to say ‘I played a part in building that bridge.’ There’s honor in a project like that, and it should be shared.” Brumer did indeed play a part in the Verrazano-Narrows Bridge, as he had in many other of Ammann’s designs.

  Milton Brumer, born in Philadelphia, was a 1923 graduate of Rennselaer Polytechnic Institute and a classmate of Werner Ammann. Beginning as a junior engineer with New York’s Interborough Rapid Transit Company, Brumer subsequently held various engineering positions, including assistant engineer for the Port of New York Authority on such projects as the Outerbridge Crossing,
Goethals Bridge, George Washington Bridge, Bayonne Bridge, and the Lincoln Tunnel. He joined Ammann’s firm in 1944 and became a partner in Ammann & Whitney in 1949. Having served as chief engineer for the Throgs Neck Bridge, he no doubt paid more day-to-day attention to that project than did Ammann. Of all the engineers at Ammann & Whitney, Brumer was most closely associated with Ammann on bridge and highway projects, “and it was on Milton Brumer that O. H. Ammann placed great reliance for the final execution” of the Narrows bridge project. Charles Whitney died before it was completed, and Brumer then became executive head of Ammann & Whitney, which had grown to have eight partners and a staff of about five hundred.

  Though Ammann may not have been constantly bent over a drawing board, bridges were never out of his sight or very far from his mind. At Ammann & Whitney daily, he could be found in “his simply styled office surrounded by renderings or photographs of some of his bridges.” A drawing of the Brooklyn Bridge was the only exception, “his way of paying tribute” to John Roebling as pioneer suspension-bridge builder. Ammann, who lived in New Jersey, also kept an apartment in Manhattan, on the thirty-second floor of the Carlyle, a hotel located at Madison Avenue and East 77th Street. From this position at the more or less geographical center of the island, he had a view of all the New York bridges that had defined his career and reputation. Confined to his apartment with a cold on the day before his eighty-fifth birthday, on March 26, 1964, he was able, with the aid of a telescope, to look at the 680-foot-tall Brooklyn tower of the bridge across the Narrows, twelve miles away and still under construction. From the bedroom window was visible his favorite bridge, and the one he considered his “greatest achievement,” the George Washington. From another window, he could see the Hell Gate, Triborough, Bronx-Whitestone, and Throgs Neck bridges. Finally, his living-room window afforded a partial view of the Bayonne and the Verrazano-Narrows bridges.