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.

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. Standi ng 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.

compass. With ski ll and experi ence, a pilot could determin e, using the turn and bank indi cator and the airspeed indica tor, if he were flyi ng straight and level. Easier said th an done. Even the legendary Charles Lindbergh was nearl y lost fl yin g in a snow storm w ith li ttl e prior practice w ith the new in strument. In recounting the ex peri ence, Li ndbergh concluded that he taught himsel f to fl y on instruments on that fri ghtening ni ght. Most pil ots caught in that situation wou ld not have lived to profit from it.

By the micl - 1920s the prob lem of fl ying in bad weather was inhibiting the growth of av iation. With fin ancial back ing from the Dani el Guggenheim Fu nd, the whole issue of fl ying in " fog" was addressed at the Fu ll F li ght Laboratory establi shed in 1928 at Mitchel Field in New York, under the direction of Jimm y Doolittle, another legend in the development of av iati on. It was intended to perfect the technology for makin g " blind" landings , an ambitious goal at that time, and onl y fu lly reliabl y achi eved today w ith soph istica ted automated landing systems makin g use of space-age technology.

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With some ideas suggested by D oo little, Elmer A. Sperry Sr. and hi s son Elmer 1r. invented the Sperry artificial horizon and the directional gyroscope. When integrated in a compact and standard grouping of in struments - including the artificial hori zon, directional gyro, airspeed indicator, altimeter, rate of climb indica tor - and supplemented by the turn and bank indicator, the pi lot has instantly avail abl e to him more information about the progress of the airpl ane than ava il ab le by looking out the w indow, even in perfectly clear wea ther.

On Sept. 24, 1929, Jimmy Doolittl e made the fi rst compl etely blind fl igh t, maki ng use of the new instruments and direction-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 struments. Whi le thi s type of tota ll y blind flight, from li ftoff to touchdown, is still not w ithin the capabi lity of the average pi lot, and in fact is not lega l except w ith the most sophisticated equipment, the instruments and techniques developed by Doolitt le and the Sperrys are the basis for today's

THE OAKLAND BAY BRIDGE. Hailed at the time of its opening in 1936 as the world's greatest bridge, it is still considered the longest combination bridge in the world. It crosses the bay from San Francisco to Oakland via Yerba-Buena Island. The bay crossing has two suspension spans with a central man-made island anchorage. These two spans of 2,300 feet each plus two side spans make the west side 9,260 feet in length. On the island there is a tunnel 500 feet long, followed by a series of truss spans east to Oakland. One of the outstanding features of the bridge is the depth of the west spans' piers, which go to 282 feet. During the Lama Prieta earthquake of October 1989, one end of a highway section dropped onto the lower section. Other than this, there was no damage to the structure. There is, however, seri ous concern about retrofitting the east spans. THE GRAND COULEE DAM. Built between 1933 and 1942 in the east central part of Washington on the Columbia River, it is one of the largest concrete structures in the world, containing 10.6 million cubic yards of concrete. It is 550 feet high, 5,223 feet in length and impounds Franklin D. Roosevelt Lake, which is 154 miles long. As in the case of .the Hoover Dam, it is used for irrigation, flood control and hydroelectric power. Presently its power output of 6,500 megawatts is second only to Itaipu in Brazil/Paraguay.

THE GOLDEN GATE

BRIDGE. Completed in 1937, this famous bridge links northern California with the peninsula of San Franci sco. Its suspension span of 4,200 feet was the longest in the world at that time. Next to the Verrazano-Narrows suspension bridge of 4,260 feet, built in 1964 in New York, it is the second longest in this country. Currently the six-lane bridge has 42 million vehicle crossings per year. While the initial cost of the bridge in 1937 was $35 million, its present-day revenue exceeds $58 million per year. Tog ether the Golden Gate and Bay bridges have played a vital role in

THE CALIFORNIA AOUEDUCT SYSTEM.

expanding the development of the bay area.

This project, the most extensive multi-billion dollar aqueduct system in the world, draws water from several sources. One source is the Colorado River at Parker Dam, where water is transported 242 miles over the San Bernardino Mountains to Lake Mathews southwest of Riverside, Calif. This system has a capacity of 1 billion gallons per day. The second portion of the system, started in 1966 and completed in 1972, begins at the Sacramento River delta near San Francisco, flows south 444 miles, and crosses over the Tehachapi Mountains to the Parris Reservoir near Los Angeles. A third part of the system feeds Los Angeles via the Los Angeles aqueduct, which takes water from the Owens River and Mono lake in the Sierra Nevada region. This aqueduct was begun in 1907 and completed in 1913; the Mono Lake connection was added in 1940. The 338-m ile system has a capacity of 4 billion gallons of water per day.

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instrument flight procedures . Such procedures are considered routine for all military and commerci al aviation and are part of the advanced training for many general aviation pilots.

Sir George Cayley in the mid- 1800s had everything basically correct for a successful airpl ane confi guration, and even flew a model glider, yet he and others interested in flight had no real chance of achieving sustained manned flight until suitable power plants became availabl e. The internal combustion engine was developed in the 1860s and 1870s, and the first automobiles were on the road in the last two decades of the 1800s. For a successful ai rpl ane engi ne, it remained for the internal combustion eng ine to evolve in a form with a hi gh power-to-weight ratio. Thi s did not happen until Langley and the Wri ght Brothers designed and built their own engi nes. For hi s full- scale airplane, Langley built a 52-horsepower engine weighing on ly 208 pounds, amazing for the time and not surpassed for about fifteen years. The Wri ght Brothers developed their own engine at 12 horsepower and 200 pounds - no match for the Langley achievement, but good enough when coupled with their scientifi call y designed propeller. The evolution of the internal combustion aircraft engine continued into World War II, when 2,200-horsepower engines boosted flight speeds to 500 miles per hour. Except fo r the lower flight speeds associated with many general av iation aircraft, IC engines are no longer in favor. In fact, most general av iati on IC engines have advanced little technologically since the 1950s.

The jet engine was not initially developed with governmental support fo r mi litary purposes. In fact , in both Great Britain and Germany, independent work began at about the same time in the early 1930s, with little interest shown by the governments. Frank Whittle first proposed the idea of jet propul sion for aircraft app li cations in a thes is in 1928 , and obtained a patent in 1930. It was not until 1935 that he obtai ned financial backing, and on April 12, 1937 , the first successful test stand demonstration of a jet engine was made. In Germany in 1936, Hans von Ohain, independently of Whittle's work, started work on an aircraft gas turbine with the financial support of Ernst Heinkel. There was parallel developmen t of the Hein kel He 178 Airplane for the engine, and on Aug. 28, 1939, the first jet-propelled

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Top 10 marvels of civil engineering

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THE INTERSTATE HIGHWAY SYSTEM. In 1944, Congress designated the National System of Interstate and Defense Highway, and in 1956, President Dwight D. Eisenhower signed the Federal-Aid Highway Act, which mandated a national system of highways to connect American cities. Although work on the system began earlier, actual completion did not occur until around 1990 at a cost of more than $100 billion. The size of this system is staggering. It includes 42,500 miles of multilane limited access highway, nearly 500,000 miles of primary rural roads and 640,000 miles of secondary roads. The interstate system has changed forever the way we travel and use our cars. It has also created a society of commuters. One major project of the 21 st century will be the repair and extension of the interstate highway system.

THE TRANS-ALASKAN PIPELINE. Started in 1974, during the height of the oi l crisis, and completed in 1977, this $8 billion project was an important factor in helping reduce our nation's dependence on foreign oil. This pipeline transports crude oil some 800 miles from Prudhoe

Bay, Alaska, to the ice-free port of Valdez. More than 11 billion barrels of oil have gone through the pipeline over the past two decades. The line runs across mountain ranges at elevations as high as 4,800 feet.

Special supports had to be built to prevent the hot line from sinking into the permafrost, and also to permit caribou crossings. airp lane fl ew. Th is was on ly a few days prior to the start of World War II. Whittle became airborne with the flight version of his jet engine only after the British government established an interest fo llowing his successful ground tests. On May 15 , 1941 , the speciall y designed Gloster E28 aircraft flew with Whittle's engine producing 860 pounds of thrust. The German government quickly became interested after the successfu l Heinkel flight demonstration , and the result was the first operational military jet fighter, the Messerschmitt Me-262, which caused the All ies serious consternation near the end of the war.

The post-war period saw rapid app lication of jet propulsion to military and commercial aircraft. Both Great Britain and the United States had commercial jet transports in the 1950s and jet fi ghters capable of supersonic fli ght entered service. The jet engine in commerc ial av iation was more efficient on most routes, was more reliable, and much more comfortable for THE KENNEDY SPACE CENTER VEHICLE ASSEMBLY BUILDING. Built in the 1960s for the vertica l assembly of the Saturn vehicles used in the Apollo lunar project. and later adapted for space shuttle vehicles, the VAB is one of the largest enclosed clear spaces in the world. It is 525 feet tall and covers a ground area of 8 acres. It was a critical component of the "space race" between the United States and the Soviet Union.

Significant projects outside the U.S.

Although I have listed American achi evements I would be rem iss in not recognizing some of the great international projects of this century. These include: • OWEN FALLS RESERVOIR, Uganda • THE HIGH ASWAN RESERVOIR, Egypt • THE PETRONAS TOWERS,

Kuala Lumpur, Malaysia • THE AKASHI KAIKYO BRIDGE, Japan. • THE STOREBELT BRIDGE, Denmark. • THE ENGLISH CHANNEl TUNNEL (the "Chunnel").

Interesting projects in progress or in the planning stage for the 21 st century include the Turukhansk Hydro Dam in Russia and the Three Gorges Dam on the Yangtze River in China. Some proposed tall buildings include a 1,537 -foot tower in Chicago and a structure, known as the India Tower, to be built in Jabalpur, India. stand at a height of 2,222 feet.

Joseph H. Senne is a professor emeritus of civil engineeri ng at UMR.

Photo Source: OiUan, Richard. High Steel: Building the Bridges Across San Francisco Bay. California, 1979. Jansen, Robert B. Dams and Public Safety. United States Government Printing Office. Denver, 1980. Morgan Alfred. The Story of Skyscrapers. New York, 1934.

The latter will be pyramid-shaped and will passengers. Interior noise, once dominated by the drone of reciprocating engines, is now reduced at most seating locations to boundary layer noi se, which is the resu lt of going fast. Modem modifications of the basic turbo-jet engine, resu lting in the turbofan engine, have further increased the efficiency of the original concept with the additional benefit of reducing the prob lem of operational noi se around airports. The contributions of Whittle and von Ohain in the 1930s have made our c UlTent air transportation system possible.

As thi s mi llennium ends and the next one begins, the frontiers of development in aeronautics are efficiency, safety, and compatibility with the environment. The developments reviewed in thi s brief hi story are the basis from which av iation wi ll continue to evolve.

Walt Eversman is a Curators' Professor of aerospace en gineering at UMR.

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