Top 10 marvels of civil engineering By Joseph Senne (jhsenne@rollanet .org)
When asked to select the 70 greatest civil engineering accomplishments of this century. I approached the assignment with some trepidation. In creating my list. I considered the scope of the project as related to the technology of its time, and the project's benefit to the public as a whole. In some cases I have considered a system rather than an individual project. Also, my selections are confined to the United States but with the recognition that the 20th century has seen a number of very beneficial achievements in other countries.
THE PANAMA CANAL. Although outside the United States, the Panama Canal was built by this country after taking over from the French. Fifty miles in length, it took 10 years to build. The canal was completed in 1914 at a cost of $350 million. The amount of excavation amounted to 232 million cubic yards of rock and earth, with the locks and dams containing 4.8 million cubic yards of concrete. The canal cut 6,835 miles off the route around Cape Horn, thereby saving much time and fuel. Between 12,000 and 15,000 ships per year go through the cana l. Ownership will be turned over to Panama at the end of this century.
compass. With ski l l and experi ence, a pilot co uld determin e, using th e turn and bank indi cator and the airspeed indica tor, if he were flyi ng straight and level. Easier said th an done. Even th e legendary Charles Lindbergh was nearl y los t fl y in g in a snow storm w ith li ttl e prior practice w ith th e new in strum ent. In recounting the ex peri ence, Li ndbergh co ncluded th at he taught himsel f to fl y on instruments on that fri ghtening ni ght. Most pil ots ca ught in that situation wou ld not have lived to profit from it. By th e micl - 1920s the prob lem of fl y ing in bad weather was inhibiting the grow th of av iation. With fin ancial back ing from the Dani el Guggenheim Fu nd , th e whole issue of fl y ing in " fog" was addressed at the Fu ll F li ght L aboratory establi shed in 1928 at Mitchel Field in New York, under the direction of Jimm y Doolittle, anoth er legend in th e development of av iati on. It was intended to perfect th e tec hnology for makin g " blind" land ings , an ambitious goa l at th at time, and onl y fu lly reliabl y achi eved today w ith soph isti ca ted automated landing systems makin g use of space-age technology.
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THE EMPIRE STATE BUILDING . Located in New York City, the Empire State Building was one of the nation's first real skyscrapers - completed in 1931 in a record time of less than two years. Standing at 1.250 feet 11,414 feet with the TV tower), it was the tallest building in the world during its time. Although now surpassed in height by the Sears Tower, the two World Trade Center towers and several structures in other countries, its elegant stepped design still makes the Empire State Building an outstand ing American skyscraper. THE HOOVER DAM. At 726 feet. it is one of the highest concrete arch dams in the world. It has a crest length of 1,244 feet and contains 3.25 million cubic yards of concrete. Located on the Colorado River near Las Vegas, Nev., construction was begun in 1931 and completed in 1936. Lake Mead, formed by the dam, is one of the largest artificially created bodies of water in the world. The dam provides irrigation for over 1 million acres, as we ll as recreation, flood control and 1,500 megawatts of power all of which helped to develop the southwest. In 1955 the American Society of Civi l Engineers selected Hoover Dam as one of the nation's seven civi l engineering wonde rs.
With some ideas suggested by D oo little, Elmer A. Sperry Sr. and hi s son El mer 1r. invented the Sperry artificial horizon and the directi onal gyroscope. When integrated in a co mpac t and standard grouping of in strum ents - including th e artificial hori zon, directiona l gyro, airspeed indicator, altimeter, rate of climb indica tor - and supplemented by the turn and bank ind icator, the pi lot has instantly avail abl e to him more information about th e progress of the airpl ane th an ava il ab le by looking out th e w indow, even in perfectly clear wea ther. On Sept. 24, 1929 , Ji mmy Doolittl e made the fi rst co mpl etely blind fl igh t, maki ng use of the new instrum ents and directi on- findin g eq uipment. Enclosed in a hood over the cockpit, and with a safety pil ot to look for other aircraft and monitor the night but not help, Doolittl e took off, fl ew a 360 degree circuit, and landed , solely w ith the use of in strumen ts. Whi le thi s type of tota ll y bl ind flight, fro m li ftoff to touchdown, is still not w ithin the capa bi lity of the average pi lot, and in fact is not lega l except w ith the most sophisticated equ ipment, the instrum ents and techniques developed by Doolitt le and th e Sperrys are the basis for today's
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