Concrete Portland cement concrete, is a composite material composed of fine and coarse aggregate bonded together with a fluid cement that hardens over time—most a lime-based cement binder, such as Portland cement, but sometimes with other hydraulic cements, such as a calcium aluminate cement. It is distinguished from other, non-cementitious types of concrete all binding some form of aggregate together, including asphalt concrete with a bitumen binder, used for road surfaces, polymer concretes that use polymers as a binder; when aggregate is mixed together with dry Portland cement and water, the mixture forms a fluid slurry, poured and molded into shape. The cement reacts chemically with the water and other ingredients to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. Additives are included in the mixture to improve the physical properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials embedded to provide tensile strength, yielding reinforced concrete.
Famous concrete structures include the Panama Canal and the Roman Pantheon. The earliest large-scale users of concrete technology were the ancient Romans, concrete was used in the Roman Empire; the Colosseum in Rome was built of concrete, the concrete dome of the Pantheon is the world's largest unreinforced concrete dome. Today, large concrete structures are made with reinforced concrete. After the Roman Empire collapsed, use of concrete became rare until the technology was redeveloped in the mid-18th century. Worldwide, concrete has overtaken steel in tonnage of material used; the word concrete comes from the Latin word "concretus", the perfect passive participle of "concrescere", from "con-" and "crescere". Small-scale production of concrete-like materials was pioneered by the Nabatean traders who occupied and controlled a series of oases and developed a small empire in the regions of southern Syria and northern Jordan from the 4th century BC, they discovered the advantages of hydraulic lime, with some self-cementing properties, by 700 BC.
They built kilns to supply mortar for the construction of rubble-wall houses, concrete floors, underground waterproof cisterns. They kept the cisterns secret; some of these structures survive to this day. In the Ancient Egyptian and Roman eras, builders discovered that adding volcanic ash to the mix allowed it to set underwater. German archaeologist Heinrich Schliemann found concrete floors, which were made of lime and pebbles, in the royal palace of Tiryns, which dates to 1400–1200 BC. Lime mortars were used in Greece and Cyprus in 800 BC; the Assyrian Jerwan Aqueduct made use of waterproof concrete. Concrete was used for construction in many ancient structures; the Romans used concrete extensively from 300 BC to a span of more than seven hundred years. During the Roman Empire, Roman concrete was made from quicklime, pozzolana and an aggregate of pumice, its widespread use in many Roman structures, a key event in the history of architecture termed the Roman Architectural Revolution, freed Roman construction from the restrictions of stone and brick materials.
It enabled revolutionary new designs in terms of both structural dimension. Concrete, as the Romans knew it, was a revolutionary material. Laid in the shape of arches and domes, it hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick. Modern tests show that opus caementicium had as much compressive strength as modern Portland-cement concrete. However, due to the absence of reinforcement, its tensile strength was far lower than modern reinforced concrete, its mode of application was different: Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice consisted of rubble. Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.
The long-term durability of Roman concrete structures has been found to be due to its use of pyroclastic rock and ash, whereby crystallization of strätlingite and the coalescence of calcium–aluminum-silicate–hydrate cementing binder helped give the concrete a greater degree of fracture resistance in seismically active environments. Roman concrete is more resistant to erosion by seawater than modern concrete; the widespread use of concrete in many Roman structures ensured that many survive to the present day. The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges, such as the magnificent Pont du Gard in southern France, have masonry cladding on a concrete core, as does the dome of the Pantheon. After the Roman Empire, the use of burned lime and pozzolana was reduced until the technique was all but forgotten between 500 and the 14th century. From the 14th century to the mid-18th century, the use of cement returned; the Canal du Midi was built using concrete in 1670.
The greatest step forward in the modern use
Federal Aviation Administration
The Federal Aviation Administration is a governmental body of the United States with powers to regulate all aspects of civil aviation in that nation as well as over its surrounding international waters. Its powers include the construction and operation of airports, air traffic management, the certification of personnel and aircraft, the protection of U. S. assets during the launch or re-entry of commercial space vehicles. Powers over neighboring international waters were delegated to the FAA by authority of the International Civil Aviation Organization. Created in August 1958, the FAA replaced the former Civil Aeronautics Administration and became an agency within the US Department of Transportation; the FAA's roles include: Regulating U. S. commercial space transportation Regulating air navigation facilities' geometric and flight inspection standards Encouraging and developing civil aeronautics, including new aviation technology Issuing, suspending, or revoking pilot certificates Regulating civil aviation to promote transportation safety in the United States through local offices called Flight Standards District Offices Developing and operating a system of air traffic control and navigation for both civil and military aircraft Researching and developing the National Airspace System and civil aeronautics Developing and carrying out programs to control aircraft noise and other environmental effects of civil aviation The FAA is divided into four "lines of business".
Each LOB has a specific role within the FAA. Airports: plans and develops projects involving airports, overseeing their construction and operations. Ensures compliance with federal regulations. Air Traffic Organization: primary duty is to safely and efficiently move air traffic within the National Airspace System. ATO employees manage air traffic facilities including Airport Traffic Control Towers and Terminal Radar Approach Control Facilities. See Airway Operational Support. Aviation Safety: Responsible for aeronautical certification of personnel and aircraft, including pilots and mechanics. Commercial Space Transportation: ensures protection of U. S. assets during the launch or reentry of commercial space vehicles. The FAA is headquartered in Washington, D. C. as well as the William J. Hughes Technical Center in Atlantic City, New Jersey, the Mike Monroney Aeronautical Center in Oklahoma City and its nine regional offices: Alaskan Region – Anchorage, Alaska Northwest Mountain – Seattle, Washington Western Pacific – Los Angeles, California Southwest – Fort Worth, Texas Central – Kansas City, Missouri Great Lakes – Chicago, Illinois Southern – Atlanta, Georgia Eastern – New York, New York New England – Boston, Massachusetts The Air Commerce Act of May 20, 1926, is the cornerstone of the federal government's regulation of civil aviation.
This landmark legislation was passed at the urging of the aviation industry, whose leaders believed the airplane could not reach its full commercial potential without federal action to improve and maintain safety standards. The Act charged the Secretary of Commerce with fostering air commerce and enforcing air traffic rules, licensing pilots, certifying aircraft, establishing airways, operating and maintaining aids to air navigation; the newly created Aeronautics Branch, operating under the Department of Commerce assumed primary responsibility for aviation oversight. In fulfilling its civil aviation responsibilities, the Department of Commerce concentrated on such functions as safety regulations and the certification of pilots and aircraft, it took over the building and operation of the nation's system of lighted airways, a task initiated by the Post Office Department. The Department of Commerce improved aeronautical radio communications—before the founding of the Federal Communications Commission in 1934, which handles most such matters today—and introduced radio beacons as an effective aid to air navigation.
The Aeronautics Branch was renamed the Bureau of Air Commerce in 1934 to reflect its enhanced status within the Department. As commercial flying increased, the Bureau encouraged a group of airlines to establish the first three centers for providing air traffic control along the airways. In 1936, the Bureau itself began to expand the ATC system; the pioneer air traffic controllers used maps and mental calculations to ensure the safe separation of aircraft traveling along designated routes between cities. In 1938, the Civil Aeronautics Act transferred the federal civil aviation responsibilities from the Commerce Department to a new independent agency, the Civil Aeronautics Authority; the legislation expanded the government's role by giving the CAA the authority and the power to regulate airline fares and to determine the routes that air carriers would serve. President Franklin D. Roosevelt split the authority into two agencies in 1940: the Civil Aeronautics Administration and the Civil Aeronautics Board.
CAA was responsible for ATC, airman and aircraft certification, safety enforcement, airway development. CAB was entrusted with safety regulation, accident investigation, economic regulation of the airlines; the CAA was part of the Department of Commerce. The CAB was an independent federal agency. On the eve of America's entry into World War II, CAA began to extend its ATC responsibilities to takeoff and landing operations at airports; this expanded role became permanent after the war. The application of radar to ATC helped controllers in their drive to keep abreast of the postwar boom in commercial air transportation. In 1946, Congress gave CAA the added task of administering the federal-aid airport program, the first peacetime program of financial assistance aimed exclusivel
According to the International Civil Aviation Organization, a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a natural surface. In January 1919, aviation pioneer Orville Wright underlined the need for "distinctly marked and prepared landing places, the preparing of the surface of reasonably flat ground an expensive undertaking there would be a continuous expense for the upkeep." Runways are named by a number between 01 and 36, the magnetic azimuth of the runway's heading in decadegrees. This heading differs from true north by the local magnetic declination. A runway numbered 09 points east, runway 18 is south, runway 27 points west and runway 36 points to the north; when taking off from or landing on runway 09, a plane is heading around 90°. A runway can be used in both directions, is named for each direction separately: e.g. "runway 15" in one direction is "runway 33" when used in the other. The two numbers differ by 18.
For clarity in radio communications, each digit in the runway name is pronounced individually: runway one-five, runway three-three, etc.. A leading zero, for example in "runway zero-six" or "runway zero-one-left", is included for all ICAO and some U. S. military airports. However, most U. S. civil aviation airports drop the leading zero. This includes some military airfields such as Cairns Army Airfield; this American anomaly may lead to inconsistencies in conversations between American pilots and controllers in other countries. It is common in a country such as Canada for a controller to clear an incoming American aircraft to, for example, runway 04, the pilot read back the clearance as runway 4. In flight simulation programs those of American origin might apply U. S. usage to airports around the world. For example, runway 05 at Halifax will appear on the program as the single digit 5 rather than 05. If there is more than one runway pointing in the same direction, each runway is identified by appending left and right to the number to identify its position — for example, runways one-five-left, one-five-center, one-five-right.
Runway zero-three-left becomes runway two-one-right. In some countries, regulations mandate that where parallel runways are too close to each other, only one may be used at a time under certain conditions. At large airports with four or more parallel runways some runway identifiers are shifted by 1 to avoid the ambiguity that would result with more than three parallel runways. For example, in Los Angeles, this system results in runways 6L, 6R, 7L, 7R though all four runways are parallel at 69°. At Dallas/Fort Worth International Airport, there are five parallel runways, named 17L, 17C, 17R, 18L, 18R, all oriented at a heading of 175.4°. An airport with only three parallel runways may use different runway identifiers, such as when a third parallel runway was opened at Phoenix Sky Harbor International Airport in 2000 to the south of existing 8R/26L — rather than confusingly becoming the "new" 8R/26L it was instead designated 7R/25L, with the former 8R/26L becoming 7L/25R and 8L/26R becoming 8/26.
Runway designations may change over time because Earth's magnetic lines drift on the surface and the magnetic direction changes. Depending on the airport location and how much drift occurs, it may be necessary to change the runway designation; as runways are designated with headings rounded to the nearest 10°, this affects some runways sooner than others. For example, if the magnetic heading of a runway is 233°, it is designated Runway 23. If the magnetic heading changes downwards by 5 degrees to 228°, the runway remains Runway 23. If on the other hand the original magnetic heading was 226°, the heading decreased by only 2 degrees to 224°, the runway becomes Runway 22; because magnetic drift itself is slow, runway designation changes are uncommon, not welcomed, as they require an accompanying change in aeronautical charts and descriptive documents. When runway designations do change at major airports, it is changed at night as taxiway signs need to be changed and the huge numbers at each end of the runway need to be repainted to the new runway designators.
In July 2009 for example, London Stansted Airport in the United Kingdom changed its runway designations from 05/23 to 04/22 during the night. For fixed-wing aircraft it is advantageous to perform takeoffs and landings into the wind to reduce takeoff or landing roll and reduce the ground speed needed to attain flying speed. Larger airports have several runways in different directions, so that one can be selected, most nearly aligned with the wind. Airports with one runway are constructed to be aligned with the prevailing wind. Compiling a wind rose is in fact one of the preliminary steps taken in constructing airport runways. Note that wind direction is given as the direction the wind is coming from: a plane taking off from runway 09 faces east, into an "east wind" blowing from 090°. Runway dimensions vary from as small as 245 m long and 8 m wide in s
An airline is a company that provides air transport services for traveling passengers and freight. Airlines utilize aircraft to supply these services and may form partnerships or alliances with other airlines for codeshare agreements. Airline companies are recognized with an air operating certificate or license issued by a governmental aviation body. Airlines vary in size, from small domestic airlines to full-service international airlines with double decker airplanes. Airline services can be categorized as being intercontinental, regional, or international, may be operated as scheduled services or charters; the largest airline is American Airlines Group. DELAG, Deutsche Luftschiffahrts-Aktiengesellschaft I was the world's first airline, it was founded on November 16, 1909, with government assistance, operated airships manufactured by The Zeppelin Corporation. Its headquarters were in Frankfurt; the first fixed wing scheduled airline was started on January 1, 1914, from St. Petersburg, Florida, to Tampa, Florida.
The four oldest non-dirigible airlines that still exist are Netherlands' KLM, Colombia's Avianca, Australia's Qantas, the Czech Republic's Czech Airlines. The earliest fixed wing airline in Europe was Aircraft Transport and Travel, formed by George Holt Thomas in 1916. Using a fleet of former military Airco DH.4A biplanes, modified to carry two passengers in the fuselage, it operated relief flights between Folkestone and Ghent. On 15 July 1919, the company flew a proving flight across the English Channel, despite a lack of support from the British government. Flown by Lt. H Shaw in an Airco DH.9 between RAF Hendon and Paris – Le Bourget Airport, the flight took 2 hours and 30 minutes at £21 per passenger. On 25 August 1919, the company used DH.16s to pioneer a regular service from Hounslow Heath Aerodrome to Le Bourget, the first regular international service in the world. The airline soon gained a reputation for reliability, despite problems with bad weather, began to attract European competition.
In November 1919, it won the first British civil airmail contract. Six Royal Air Force Airco DH.9A aircraft were lent to the company, to operate the airmail service between Hawkinge and Cologne. In 1920, they were returned to the Royal Air Force. Other British competitors were quick to follow – Handley Page Transport was established in 1919 and used the company's converted wartime Type O/400 bombers with a capacity for 12 passengers, to run a London-Paris passenger service; the first French airline was Société des lignes Latécoère known as Aéropostale, which started its first service in late 1918 to Spain. The Société Générale des Transports Aériens was created in late 1919, by the Farman brothers and the Farman F.60 Goliath plane flew scheduled services from Toussus-le-Noble to Kenley, near Croydon, England. Another early French airline was the Compagnie des Messageries Aériennes, established in 1919 by Louis-Charles Breguet, offering a mail and freight service between Le Bourget Airport and Lesquin Airport, Lille.
The first German airline to use heavier than air aircraft was Deutsche Luft-Reederei established in 1917 which started operating in February 1919. In its first year, the D. L. R. Operated scheduled flights on routes with a combined length of nearly 1000 miles. By 1921 the D. L. R. Network was more than 3000 km long, included destinations in the Netherlands and the Baltic Republics. Another important German airline was Junkers Luftverkehr, which began operations in 1921, it was a division of the aircraft manufacturer Junkers, which became a separate company in 1924. It operated joint-venture airlines in Austria, Estonia, Hungary, Norway, Poland and Switzerland; the Dutch airline KLM made its first flight in 1920, is the oldest continuously operating airline in the world. Established by aviator Albert Plesman, it was awarded a "Royal" predicate from Queen Wilhelmina, its first flight was from Croydon Airport, London to Amsterdam, using a leased Aircraft Transport and Travel DH-16, carrying two British journalists and a number of newspapers.
In 1921, KLM started scheduled services. In Finland, the charter establishing Aero O/Y was signed in the city of Helsinki on September 12, 1923. Junkers F.13 D-335 became the first aircraft of the company, when Aero took delivery of it on March 14, 1924. The first flight was between Helsinki and Tallinn, capital of Estonia, it took place on March 20, 1924, one week later. In the Soviet Union, the Chief Administration of the Civil Air Fleet was established in 1921. One of its first acts was to help found Deutsch-Russische Luftverkehrs A. G. a German-Russian joint venture to provide air transport from Russia to the West. Domestic air service began around the same time, when Dobrolyot started operations on 15 July 1923 between Moscow and Nizhni Novgorod. Since 1932 all operations had been carried under the name Aeroflot. Early European airlines tended to favor comfort – the passenger cabins were spacious with luxurious interiors – over speed and efficiency; the basic navigational capabilities of pilots at the time meant that delays due to the weather were commonplace.
By the early 1920s, small airlines were struggling to compete, there was a movement towards increased rationalization and consolidation. In 1924, Imperial Airways was formed from the merger of Instone Air Line Company, British Marine Air Navigation, Daimler Airway and Handley Page Transport Co Ltd. to allow British airlines to compete with stiff competition from French and German airlines that were enjoying heavy government subsidies. The ai
Chippewa County, Wisconsin
Chippewa County is a county located in the U. S. state of Wisconsin. As of the 2010 census, the population was 62,415, its county seat is Chippewa Falls. The county was founded in 1845 from Crawford County in the Wisconsin Territory, organized in 1853. Chippewa County is included in the Eau Claire, WI Metropolitan Statistical Area as well as the Eau Claire-Menomonie, WI Combined Statistical Area. According to the U. S. Census Bureau, the county has a total area of 1,041 square miles, of which 1,008 square miles is land and 33 square miles is water. Rusk County – north Taylor County – east Clark County – southeast Eau Claire County – south Dunn County – west Barron County – northwest KEAU - Chippewa Valley Regional Airport 4WI9 - Cornell Municipal Airport As of the census of 2000, there were 55,195 people, 21,356 households, 15,013 families residing in the county; the population density was 55 people per square mile. There were 22,821 housing units at an average density of 23 per square mile; the racial makeup of the county was 97.85% White, 0.16% Black or African American, 0.32% Native American, 0.89% Asian, 0.01% Pacific Islander, 0.17% from other races, 0.60% from two or more races.
0.52% of the population were Hispanic or Latino of any race. 44.1% were of German, 15.8% Norwegian and 5.8% Irish ancestry. There were 21,356 households out of which 33.70% had children under the age of 18 living with them, 58.30% were married couples living together, 8.00% had a female householder with no husband present, 29.70% were non-families. 24.70% of all households were made up of individuals and 11.00% had someone living alone, 65 years of age or older. The average household size was 2.53 and the average family size was 3.03. In the county, the population was spread out with 26.50% under the age of 18, 7.70% from 18 to 24, 28.20% from 25 to 44, 23.10% from 45 to 64, 14.60% who were 65 years of age or older. The median age was 38 years. For every 100 females, there were 99.10 males. For every 100 females age 18 and over, there were 96.00 males. The largest employers in Chippewa County are: The University of Wisconsin-Eau Claire's Special Collections and Archives, located on the fifth floor of McIntyre Library, houses an extensive collection of public records and collections relating to Chippewa County.
In addition to vital records dating to 1907, there are naturalization records, census records, civil and circuit court records. These resources are popular with local genealogists. Within the local history collection, there are books about immigration to the region, logging and cemetery records, reminiscences by local residents, a number of histories and biographies compiled by local historians. Special Collections and Archives houses numerous archives files which relate to Chippewa County. There are many collections which pertain to the railway industry and agriculture; the University of Wisconsin-Eau Claire's Special Collections and Archives includes information for Buffalo, Eau Claire and Taylor counties. Bloomer Chippewa Falls Cornell Eau Claire Stanley Boyd Cadott Lake Hallie New Auburn Holcombe Jim Falls Lake Wissota National Register of Historic Places listings in Chippewa County, Wisconsin Forrester, George Historical and Biographical Album of the Chippewa Valley Wisconsin. Chicago: A. Warner, 1891-2.
Randall, Thomas E. History of the Chippewa Valley. Eau Claire, Wis.: Free Press, 1875. Chippewa County government website Chippewa County map from the Wisconsin Department of Transportation Chippewa County Historical Society University of Wisconsin-Eau Claire, Special Collections and Archives
Republic Airlines (1979–1986)
Republic Airlines was a United States airline formed by the merger of North Central Airlines and Southern Airways on July 1, 1979. Their headquarters were at Minneapolis-St. Paul International Airport, in what is now Fort Snelling in unincorporated Hennepin County, Minnesota; the former headquarters is now Delta Air Lines Building C. Republic was acquired by and merged into Northwest Airlines in 1986. Republic Airlines began in 1979 with the merger of North Central Airlines and Southern Airways, the first under airline deregulation; the new airline's headquarters were at Minneapolis-Saint Paul International Airport, though their largest hub was at Detroit Metropolitan Wayne County Airport. Following their buyout of Hughes Airwest in 1980, Republic became the largest airline in the U. S. by number of airports served. The company operated the world's largest Douglas DC-9 fleet, with DC-9-10, DC-9-30 and DC-9-50s and flew Boeing 727-200, Boeing 757-200 and McDonnell Douglas MD-80 jets. In addition, Republic operated Convair 580 turboprops flown by North Central.
After the merger, losses mounted and service reductions followed. Saddled with debt from two acquisitions and new aircraft, the airline struggled in the early 1980s, introduced a human mascot version of Herman the Duck, they reduced service to Phoenix, a former hub of Hughes Airwest, citing their inability to compete with non-union airlines there and dismantled the former extensive route system operated by Hughes Airwest in the western U. S. In 1986 Northwest Orient Airlines announced on January 23 that they would buy Republic for $884 million in response to United Airlines' purchase of the Pacific routes of Pan American World Airways and to provide domestic feed. Opposed by the Justice Department, the Northwest-Republic merger was approved by the Transportation Department on July 31 and was completed on October 1, with Northwest dropping the word Orient from their name after the merger. Republic's hubs at Minneapolis and Detroit became the backbone of Northwest's domestic network. Northwest merged with Delta Air Lines in 2008.
Republic's hubs in Detroit and the Twin Cities have remained intact with Delta. 133 DC-9 aircraft - Douglas DC-9-14. C./Virginia Washington Dulles Airport Washington National Airport Washington state Seattle Wisconsin Appleton Eau Claire Green Bay La Crosse Madison Milwaukee Wausau Canada Calgary, Alberta Edmonton, Alberta Montreal, Quebec Toronto, OntarioCayman Islands Grand CaymanMexico Cancun Puerto Vallarta Mazatlan GuadalajaraRepublic previously served Winnipeg, Manitoba in Canada, served by Nort
O'Hare International Airport
O'Hare International Airport referred to as O'Hare Airport, Chicago O'Hare, or O'Hare, is an international airport located on the far Northwest Side of Chicago, Illinois, 14 miles northwest of the Loop business district, operated by the Chicago Department of Aviation and covering 7,627 acres. O'Hare has non-stop flights to 228 destinations in North America, South America, Africa and Oceania. Established to be the successor to Chicago’s "busiest square mile in the world", Midway Airport, O'Hare began as an airfield serving a Douglas manufacturing plant for C-54 military transports during World War II, it was named for Edward "Butch" O'Hare, the U. S. Navy's first Medal of Honor recipient during that war. At the height of the Cold War, O'Hare served as an active fighter base for the Air Force; as the first major airport planned post-war, O’Hare's innovative design pioneered concepts such as concourses, direct highway access to the terminal, jet bridges, underground refueling systems. It became famous as the first World’s Busiest Airport of the jet age, holding that distinction from 1963 to 1998.
O'Hare is unusual in that it serves a major hub for more than one of the three U. S. mainline carriers. It is a focus city for Frontier Airlines and Spirit Airlines. While Terminals 2 and 3 remain of the original design, the airport has been engaged in a massive modernization of the airfield, is beginning an expansion of passenger facilities that will remake it as North America’s first airport built around airline alliances. Not long after the opening of Midway Airport in 1926, the City of Chicago realized that additional airport capacity would be needed in the future; the city government investigated various potential airport sites during the 1930s, but made little progress prior to America's entry into World War II. O'Hare's place in aviation began with a manufacturing plant for Douglas C-54s during WWII; the site was known as Orchard Place, had been a small German farming community. The 2,000,000 square feet plant, located in the northeast corner of what is now the airport property, needed easy access to the workforce of the nation's second-largest city, as well as its extensive railroad infrastructure and location far from enemy threat.
Some 655 C-54s were built at the plant. The attached airfield, from which the completed planes were flown out, was known as Douglas Airport. Less known is the fact that it was the location of the Army Air Force’s 803rd Specialized Depot, a unit charged with storing many captured enemy aircraft. A few representatives of this collection would be transferred to the Smithsonian Institution's National Air and Space Museum. Douglas Company's contract ended in 1945 and, though consideration was given to building commercial aircraft at Orchard, the company chose to concentrate commercial production at its original headquarters in Santa Monica, CA. With the departure of Douglas, the complex took the name of Orchard Field Airport, was assigned the IATA code ORD; the United States Air Force used the field extensively during the Korean War, at which time there was still no scheduled commercial service at the airport. Although not its primary base in the area, the Air Force used O'Hare as an active fighter base.
By 1960, the need for O'Hare as an active duty fighter base was diminishing, just as commercial business was picking up at the airport. The Air Force removed active-duty units from O'Hare and turned the station over to Continental Air Command, enabling them to base reserve and Air National Guard units there; as a result of a 1993 agreement between the City and the Department of Defense, the reserve based was closed on April 1, 1997, ending its career as the home of the 928th Airlift Wing. At that time, the 357 acre site came under the ownership of the Chicago Department of Aviation. In 1945, Chicago mayor Edward Kelly established a formal board to choose the site of a new facility to meet future aviation demands. After considering various proposals, the board decided upon the Orchard Field site, acquired most of the federal government property in March 1946; the military retained a small parcel of property on the site, the rights to use 25% of the airfield's operating capacity for free. Ralph H. Burke devised an airport master plan based on the pioneering idea of what he called "split finger terminals", allowing a terminal building to be attached to "airline wings", each providing space for gates and planes.
Other innovations Burke brought to the O'Hare design included underground refueling, direct highway access to the front of terminals, direct rail access, all of which are utilized at airports worldwide today. O'Hare was the site of the world's first jet bridge in 1958, adapted slip form paving, developed for the nation's new Interstate highway system, for seamless concrete runways. In 1949, the City renamed the facility O'Hare Field to honor Edward "Butch" O'Hare, the U. S. Navy's first flying ace and Medal of Honor recipient in World War II, its IATA code remained unchanged, resulting in O'Hare's being one of the few IATA codes bearing no connection to the airport's name or metropolitan area. Scheduled passenger service began in 1955. Although Chicago h