单项选择题
| Alexandre-Gustave Boenickhausen Eiffel
was one of the 19th century’s master builders. Wielding iron in new ways, he
built bridges for the century’s burgeoning railways in Europe, South America and
Indochina. And after sculptor Frederic Auguste Bartholdi designed a colossal,
151-foot statue of copper sheets in 1871, he turned to France’s magician of iron
for its internal skeleton. Thus Eiffel was instrumental in creating two of the
best-known monuments to liberty in the modern world—the Statue of Liberty and
the Eiffel Tower, which was built to mark the centennial of the French
Revolution. During the Nazi occupation in World War II, the tower’ s personnel sabotaged the elevators to deprive the enemy of a view of Paris. (Hitler, who refused to climb the 1710 steps to the top, posed for his picture with the tower in the background. ) The city knew liberation was at hand on August 25, 1944, when two Parisians, braving bullets ricocheting through the girders, tore down the swastika and hoisted the tricolor. The tower illustrates Eiffel’s genius for meticulous, innovative engineering. After he had set massive stone foundations beside the Seine, four giant leaning pillars, encompassing four acres, were joined 200 feet up at the first platform, an iron belt of trusses running from pillar to pillar. This belt had to be perfectly horizontal; if out of line by a hair, the structure would tilt disastrously at 1000 feet. Eiffel’ s solution: hydraulic jacks embedded in each 440-ton column, enabling him to fine-tune its angle perfectly. Next, Eiffel deployed creeper cranes that climbed the tower as it grew, helping to hoist 15000 girders and 2.5 million rivets to the exact spot where needed. Astonishingly, the tower was completed in only two years and two months for three percent less than its $ 1.5-million budget, with no fatalities among the 250 workers. Thanks to Eiffel’s mastery of design, the tower gives the wind little to seize. Seen from certain angles, the oddly beautiful tracery of intersecting iron beams appears almost transparent. The tower is so light that pressure on the foundations is only about 60 pounds per square inch—not much more than a well-fed gentleman exerts on the floor when sitting in a chair. |