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

by Henry Petroski

  Steinman seemed to seek and need the limelight as a flower does the sunlight, and no one knew this more objectively than the press: “Editorial offices for years have been on the receiving end of the Steinman mail—poems, itineraries, news releases, pictures.” Although little of the material was usable to editors, it did call constant attention to the profession of engineering. It was estimated that no other engineer since Herbert Hoover or Charles Kettering, the crusty inventor of the electric starter for automobiles, had done more in his time to make engineering known to the public, and in Steinman’s case, “he identified himself, indeed integrated himself, with his profession so thoroughly that it would be difficult to say what effort he puts forth for self and which for his profession.” Though this perhaps self-generated confusion of himself with engineering did not win the approval of some of Steinman’s contemporary engineers, such as Ammann, it was in the final analysis a true measure of the man.

  When Steinman died, a little more than a year after the assessment of him appeared in Engineering News-Record, the journal editorialized on “Dave Steinman” with the same ambivalence, noting that, “unfortunately, his great accomplishments were sometimes clouded by his personality, which frequently made him the center of controversy.” He was likened in ego and outspokenness to Frank Lloyd Wright, and was said to have done for engineering in his lifetime what Wright did for architecture in his. The question of Steinman’s “real contribution” still irked the editors, however. They allowed that he “personified civil engineering” and that he was a “nearly unique” interpreter of his profession to the public, leaving behind too few to fill this important role, but in the end they would not grant him the accolade he no doubt would have most wanted to hear. Not one of his bridges was named in the editorial, not even the great Mackinac or his dream Liberty or his proposed Messina Strait. Instead, the magazine whose predecessor forty-seven years earlier had run a picture of Steinman’s first bridge, the modest timber cantilever he built with a troop of Boy Scouts in Idaho, grouped all of his structural achievements anonymously into a single sentence that at the same time negated them: “His bridges, which will remain as great monuments to him, would probably have been designed by others if he had not come along.”

  David Steinman the self-promoter, shown here posing among the floor-stay and suspender cables of the Brooklyn Bridge (photo credit 6.17)

  Though this kick at the casket might be in one sense true, it diminishes more the editor’s credibility as a student of engineering than the greatness of Steinman’s accomplishments. No doubt, had Steinman and his colleagues not designed and built the Mackinac Bridge in Michigan, the Deer Isle Bridge in Maine, the St. Johns Bridge in Oregon, the Carquinez Straits Bridge in California, the Florianópolis Bridge in Brazil, or even the timber cantilever in Idaho, those places might have had their bridges sooner or later, by others if Steinman had not come along. But can anyone, after knowing how the personality of the engineer informs his designs, believe that any of Steinman’s bridges would be quite the same span if designed by another? The Liberty Bridge remained a paper bridge, because the Verrazano-Narrows was built—clearly an Ammann bridge, rooted in the same aesthetic as his George Washington and Bronx-Whitestone bridges. Had Ammann not come along and filled the role of chief bridge engineer for the fledgling Port Authority, who knows what the George Washington Bridge and all its descendants would look like today? There is little doubt that bridges would stand where they do now, but they would be different bridges, embodying the personal style and ideas of whoever’s bridges they were, and they would affect our present sense of bridgeness differently than do those that actually exist. Eads, Cooper, Lindenthal, Ammann, and Steinman each built his own kind of bridge in his own time, and each of them has left a legacy that has influenced the bridges and bridge builders that have followed. This is, and will always be, the essence of the endeavor.

  REALIZE

  The great bridges of the great engineers remain as spectacular today as they were when they were dedicated, but even the greatest bridges may be least appreciated by those who benefit most from them. A search for a more efficient means than ferries to move railroad trains and then motor vehicles impelled the engineers of the century of bridge building that extended from the 1840s to the 1930s to design more and more ambitious spans. However, unless these bridges are approached with a proper perspective, whether by the armchair traveler from behind a book or the actual traveler from behind a steering wheel, their greatness and achievement can hardly be appreciated. The right of way that approaches a massive cantilever head-on affords no view of the bridge to speak of, and the way across can appear from a train window to be little more than a long series of slanted steel obstructions to the view of a majestic river. The whoosh-whoosh-whoosh of relative motion gives no hint of the human dreams and drama that began over a blank and silent drawing board.

  The view from the rear seat of an automobile can give us no better a perspective of a highway bridge, especially if it is one on a straight and heavily trafficked road. Who can really appreciate the structural-engineering achievement of a spectacular bridge when traveling in one car among hundreds in one of several lanes and at the same time trying to help the driver pick out the one relevant sign for the next connecting road on the interstate-highway route? Sometimes we can ride over bridges of immense technical achievement without even sensing their magnitude or grandeur or knowing that we are on a bridge at all. This is especially true of arch bridges whose structural muscle lies wholly below the roadway and so is invisible from the road. One such bridge is the Rio Grande High Bridge, which carries U.S. Route 64 over the gorge of the Rio Grande River in northern New Mexico. Traveling west on this route from Taos, one encounters what appears to be a remarkably flat plain extending for miles, essentially unobstructed by vertical vegetation or human artifacts. From the level of the road approaching it, the gorge itself is an invisible cut in the plain, and its great depth can only be appreciated by parking the car and leaning over the parapet on one of the slight outward extensions of the bridge so thoughtfully provided for sightseers, from which the great steel arch below may seem to make the gorge appear even deeper than it is. Such virtually invisible and largely anonymous bridges are numberless on the numbered roads across America, on the winding Pacific Coast road, in the gouged land of the Southwest, in the hilly land of the East, and even in the flat Midwest, where bridge approaches rise like Indian mounds to carry local traffic over the interstate.

  The Bixby Creek Bridge, a reinforced concrete arch, on California’s coastal highway (photo credit 7.1)

  Ironically, the greatest bridges and the ones that we tend to approach from the most favorable prospects are those in large and crowded cities, where the buildings push the roadways almost into the water, so that they must spiral back toward the bridge as if drawn to its grandeur. In New York City, for example, one has a spectacular view of the George Washington Bridge for what seems like miles when approaching it from the south on the West Side Highway and the Henry Hudson Parkway. In rush hour, the traffic on this road is often stop-and-go, and when it is stopped one can admire Othmar Ammann’s masterpiece and reflect upon how much more convenient than ferries it nonetheless is for crossing the Hudson. At night, looking out the window of a terrace restaurant just east of Columbia University, one can see, over the rooftops of Manhattan to the north, the overwhelming scale of the bridge outlined in lights. Over the rooftops to the east, the lighted outline of the Triborough Bridge looms, and, beyond it, that of the Bronx-Whitestone. As one drives south on the FDR Drive, New York City’s oldest suspended structures—the Williamsburg, Manhattan, and Brooklyn bridges—appear in sequence; driving under their approach spans and beside their towers provides a sense of scale that is missing in a drive over them. In San Francisco, the towers of the Golden Gate and Bay bridges dominate so many views that they have become defining landmarks of the city by the bay.

  Although perhaps less appreciated visually, the importance of t
he Bay Bridge for communication between San Francisco and Oakland was demonstrated when a section of its upper deck fell onto its lower one during the 1989 Loma Prieta Earthquake, closing both roadways for about a month. The Northridge Earthquake, which struck Los Angeles in 1994, demonstrated further the vital link that a major bridge provides in a highway system. With key bridges out, Los Angeles commuters found themselves stuck in day-long traffic jams on detours in the early days following the disaster. Similar frustrations occurred in Connecticut in 1983, when a section of a bridge over the Mianus River fell without warning, leaving a gap in the heavily traveled Interstate 95. Though traffic was rerouted through neighboring towns, drivers were frustrated and residents annoyed until the bridge section was replaced.

  Barring accidents, bridges, like health, are most appreciated when they begin to deteriorate and fail. Thus politicians seemed to become interested in bridges when they found that so many of them were structurally deficient. In 1992, for example, this included about one out of every five of the half-million or so bridges in the United States—an improvement over some previous years. Among the most dramatic stories is of a bridge whose condition began to deteriorate almost from its beginning. The Williamsburg Bridge is said to have been “born of a dare” when Leffert Buck was challenged to “build a bridge longer than the Brooklyn Bridge, in half the time and with less money,” and the span appeared to have fulfilled the requirements when it opened in 1903. Buck achieved the time and cost savings in part by coating the wire strands in the bridge’s four cables with graphite and linseed oil rather than galvanizing them with a molten-zinc mixture, as had been done with the Brooklyn. At the time, the procedure was considered radically different, and the wisdom of the decision came under serious question when broken wires and corrosion were discovered in the cables before the bridge was a decade old. Before it was two decades old, the bridge’s cables were wrapped in a galvanized steel cover, but severe rusting continued inside. When the bridge was forty years old, hundreds of gallons of linseed oil were poured onto the cables at the tops of the towers, with the expectation that it would seep down the cables and into their interstices and slow the corrosion. Two decades later, the procedure was repeated, with fish oil and mineral spirits. In the meantime, painting of the steel in the towers and roadway had been neglected, and so they had also developed severe rusting. Other East River bridges—the Brooklyn, Manhattan, and Queensboro—had also been the victims of deferred maintenance, blamed on a period of fiscal crisis that had struck New York, and by the mid-1980s they were undergoing repair and rehabilitation work costing on the order of half a billion dollars.

  The serious deterioration of the cables of the Williamsburg Bridge put it in a category of its own, however, and a major decision presented itself: should the bridge be fixed, or should it be torn down and replaced by a new structure? Replacing the cables without closing the bridge was likened to “restringing a pearl necklace while it is around someone’s neck,” but building an entirely new bridge “in this era of environmental impact statements” was thought to invite “legal challenges that could result in substantial delays.” Several proposals that might be described as “radical” were considered. One involved erecting new towers over the old ones and hanging a new deck under the old, which traffic would continue to use during construction. When the new deck was finished, the old one could be closed and demolished, after which the new deck could be moved into position to receive traffic. A second proposal involved first building narrow new bridges on each side of the old, then tearing down the deteriorated bridge and building a third bridge in its place, and finally joining all three to provide a wide new roadway. Still another proposal called for building two larger bridges on either side of the old one, tearing it down, and then moving the two new bridges entire toward each other to be joined together as a unit. While such proposals were being considered, the engineering firm of Steinman, Boynton, Gronquist & Birdsall was monitoring strain gauges that it had installed on the eyebars connecting the cables to the anchorages, in order to have advance warning of any accelerated deterioration of rusted wires. The consulting engineers were effectively using a technique introduced by their progenitor, David Steinman, seventy years earlier, when he wanted to check theory with reality on the Hell Gate Bridge. But just as the Williamsburg situation was described as “a case study of how not to treat a bridge as well as how not to build one,” the Hell Gate itself was at the same time the subject of a different kind of scrutiny.

  In the late 1980s, New York Senator Daniel Patrick Moynihan was made aware that the Hell Gate Bridge had not been painted in fifty-odd years, except for the daring work of graffiti artists who had left their marks high atop the stone parapets and steel arches. Since Moynihan had lived for a while as a child in Astoria, known mostly as the site of the Steinway piano factory but also as the eastern approach to the Hell Gate, he took a special interest in the bridge, which he called “a great engineering miracle.” Moynihan, who was chairman of the Subcommittee on Water Resources, Transportation, and Infrastructure of the Committee on Environment and Public Works, was disappointed that no one at either Amtrak or the Department of Transportation appeared to have an interest in the bridge. He was further annoyed when his inquiring letter to the Department of Transportation brought no response, and so he held a special hearing on Capitol Hill to discuss the matter. The nearby Triborough Bridge, he pointed out, was constantly being painted by a crew that did nothing else, and that was the way to take care of a bridge so that it did not rust away. Not all bridges, unfortunately, were under the watchful care of an agency like New York’s Triborough Bridge and Tunnel Authority, which collected sufficient tolls to maintain its works.

  Moynihan pointed out that generally we were “disinvesting in the American plant” and that “the national roof is leaking.” The estimate for painting the Hell Gate Bridge was $43 million, however, about a third of which would have to be spent just in removing the accumulated rust and dealing in an environmentally sound way with the lead-based paint that still covered the bridge here and there. Since the heavy steel bridge was deemed structurally sound by W. Graham Claytor, Jr., president and chairman of Amtrak, he had little sympathy for spending so many millions of dollars for “cosmetic purposes.” So reported The New Yorker in a story on the city’s “eighth bridge” in early 1991. Whether or not he needed such a story to push him to persist, before the year was out Senator Moynihan had worked the halls of Congress, and $55 million had been appropriated to repair and repaint the Hell Gate Bridge, “the least famous of the eight across the East River,” but the one dearest to the senator’s heart. Not every bridge has such influential friends.

  The appropriation of the money was only the first step in getting the Hell Gate Bridge painted, however. In the spring of the following year, a special train carried Moynihan, Mayor David Dinkins, and other local politicians to the bridge for a ceremonial first brushstroke, as The New Yorker reported. The ceremony had a special twist to it, for the key bridge link in the northeast corridor rail line between Boston and Washington was to be painted “an entirely new color—Hell Gate Red!” The color had been chosen by a “committee of color experts,” which included architects, a representative of the Municipal Art Society, the “minimalist painter” Robert Ryman, and the “color consultants” Taffy Dahl and Donald Kaufman from the firm Donald Kaufman Color. A press kit described the new color as “deep cool red” and placed it in “the family of red colors historically associated with railroads,” so that the Hell Gate would be readily distinguished from the city’s automobile bridges. No mention was made of the distinctive red that had covered the Forth Bridge for a century. The consultants’ color was to “complement the greens and blues of the landscape, adding to the richness of the scene,” which made it sound as if the bridge were in a pristine natural setting rather than the litter-strewn, graffiti-pocked center of New York. Proponents of the color appeared to consider as a plus that it also would “disguise any rust that d
eveloped on the bridge”; no one seems to have mentioned that this should not be the point of a paint job. Paint should serve a prophylactic as well as a cosmetic purpose, but, rather than disguise rust, it might be better to highlight any that might begin to develop, so that it could be attended to before it spread too far.

  When the train arrived at the bridge, dignitaries and reporters alike noted the considerable number of holes in the walkway of the aging bridge. However, the order of business was not to repair the structure but to apply the ceremonial first strokes of paint. Shortly after the mayor and the senator began wielding their rollers, observers saw that the color was not quite what they had been led to believe was Hell Gate Red. To some it looked like “sort of a vermilion,” to others a pink. The representative of the Municipal Art Society assured Senator Moynihan that after the appropriate number of coats, the paint would dry to the appropriate color, that in fact the ceremonial paint was a benign latex substitute for the real thing, whose fumes, it was feared, would have “knocked out half the Democratic leadership of the city.”

  The story of painting the Hell Gate is full of art and artifice, of politics and chicanery. The engineers—Lindenthal and his assistants, Ammann and Steinman—and their engineering of the structure seventy-five years earlier were not a part of the story or the event in the early 1990s. They had by and large been forgotten in the hoopla of color consultants and committees, who will no doubt ignore the bridge for another several decades at least, especially if its rust is disguised by its color. To the engineer, painting a bridge is as necessary as changing the oil in a car; it is neglected at the peril of the machine, which at least one architect, Le Corbusier, understood did not have to have grossly moving parts. Every bridge is a machine of sorts, moving ever so slightly under the action of the traffic, the push of the wind, the heat of the sun, or the growth of the rust that should not be allowed. Arresting rust and other deleterious movements of a bridge are matters for sound engineering, not for sound-byte politics. It has been estimated that as much as 2 percent of new-construction cost should be earmarked each year for maintenance, including painting, for the life of a major bridge structure. Neglect, euphemistically called “deferment,” of maintenance is only postponement of the inevitable, as the cases of the Williamsburg and Hell Gate bridges so forcefully demonstrate.