The glory of Osman

It is called the most beautiful bridge in the world. 193 1 When it opened, it was undoubtedly the longest single span. In order to commemorate the engineering achievements it represents, a stamp with pictures was issued, which became the theme of music and even a children's book. However, the sling of a George Washington Bridge collected by the National Museum of American History can only imply such glory. With a diameter of 3 feet and a length of 65,438+00 feet, this huge cylinder weighs an ugly 34,000 pounds. 26,474 steel wires extend from the end and are sealed under a pressure of 400 tons. Before the advent of computers, this experimental part helped engineers to simulate the influence of pressure on the completed cables. Today, it represents an engineering miracle, and its creation spans half a century of depression, politics and the era of two greatest American bridge designers.

No matter when it is completed, the first bridge across the Hudson River from New Jersey to new york is destined to be famous. After the Civil War, the single span was determined as the most suitable wide and busy river in the west of this rapidly developing metropolis. But materials and engineering technology are far behind the dream.

Until 1888. Just five years after John Roblin's Brooklyn Bridge (the longest suspension bridge in the world at that time) collapsed, Gustav Lindenthal, a 38-year-old Austrian engineer, proposed a suspension bridge across the Hudson River. This is a great mixture: six tracks, with a total length of more than a mile. Its central span is almost twice that of Roblin's masterpiece,

Great engineering achievements require greater imagination. In both respects, Linden Sol is very qualified. He has almost no formal education, his physique meets his dreams, and he has taught himself the basic knowledge of English and engineering. After immigrating to America, 65438-0874 made a rapid fortune in his own land, where engineers are better at thinking and practicing than college graduates.

By the turn of the century, Lyndon Sol had become very famous among his peers. His bridge at Pittsburgh Seventh Street and Smithfield Street was one of the most important bridges of their time. 1902, Linden Sol became the special envoy of new york Bridge, and this political appointment gave him considerable power and prestige as an engineer and designer. But the bridge he dreamed of has not been built yet. Although the War Department approved Lindensol's Hudson River Bridge project, a competitor sued to stop the project. By the time the case was closed, 19 of the Great Depression in the early 1990s had exhausted most of the funds. 1903 After the city election, Lindenthal was appointed as an ambassador. He found himself in a strange position, selling the new design of the Hudson River Bridge to countless interested groups-there was no agreement on site selection, cost or funds.

At the same time, the city is developing. By 19 12, Lindensol was busy completing the plan to build a railway bridge. This railway bridge is actually the longest steel arch bridge in the world, spanning the dangerous passage called the Hell's Gate between Manhattan and Queens. In order to help complete this task, this solemn designer took over a 33-year-old assistant who just came from Switzerland.

Small, quiet, and steely-willed, osma Amman looks the opposite of tall, bluffing and well-educated Lindenthal. Contrary to Lindenthal's occasional claim, Amman's degree comes from a Swiss polytechnic that is considered to be the most prestigious in the world. Amman was deeply impressed by his tutor, who was one of the most outstanding bridge builders in the world. He was rewarded. "I estimate that an engineer's ability is one-third of his personality, one-third of his ability and one-third of his experience," Amman recalled what Lindensol had said before upgrading his outstanding work on the Hell's Gate Bridge project.

After all this, Lindensol's dream of crossing the Hudson River continues. But the great achievement of 1888.

In the relentless depression, the bridge became the savior of steel. The project was completed six months ahead of schedule and cost less than the initial allocation of $60 million. The New York Times's title is "Three quarters of a century's dream has come true". 193110/On October 24th, in front of thousands of audiences, a new bridge named after new york Governor franklin roosevelt (who is about to become president) and New Jersey Governor Morgan Larson was opened to traffic. In order to show respect for the mentor, Amman and Gustav Lindensol drove to the bridge where the old man's lifelong dream was fruitless.

More revolutionary than its length, because this bridge lacks the mon design function. Before George Washington, modern suspension bridges were strengthened with steel trusses and beams to limit the movement in traffic and wind (this is an important consideration when the length of the bridge is large relative to the width and depth, just like George Washington). However, this kind of reinforcement will often reduce the attractiveness of the bridge, increase the thickness of the bridge deck and increase the cost. Amman's reason is that the absolute weight of his span, as well as the necessary heavy cables, itself can provide enough rigidity.

George Washington's resulting slender outline-viewed from the side or from above-inspired the engineer's aesthetic feeling. Only six years later, the Golden Gate Bridge shocked the world with a narrower and larger span. If these slender and relatively light bridges are sometimes uncomfortably flexible in the breeze (as drivers and engineers point out), they are also worth seeing. 1940,

However, Amman's extreme innovation is manifested in the proper nickname "Flying Getty", also known as Taa narrow bridge, which is induced by wind. After investigating the famous failure, Amman wrote: "Its small weight and extreme narrowness have completely exposed that this practice has gone too far."

It was in the early 1960s that George Washington's lower deck was added (as originally planned), and Amman almost eclipsed his mentor. Another work by Amman in 193 1 connected Staten Island and Bayon Bridge in New Jersey. It was not until 1977 that it became the largest steel arch bridge in the world, which was 600 feet longer than the previous record holder Lindenthal's Hell's Gate Bridge, and it was one of several before his death in 1965.

Amman stared through a telescope from his 32nd-floor apartment in Manhattan. In his viewfinder, a new scene appeared 12 miles away: his D-razzano narrowed the suspension bridge. As if praising the great engineering ability of George Washington Bridge in Amman, this equally slender and elegant span will not exceed its length in the next 17 years.