Modern (18th-20th Century)

The Louisville-Nashville Railroad Bridge, constructed in 1857-1859 as part of the Louisville-Nashville Railway System, spans the Green River and is still used by trains of the current CSX system in its reconstructed form. During the construction of the L&N railroad, the Green River presented a formidable obstacle that had to be surmounted. A well-known construction engineer from Germany, Albert Fink, was hired to design and supervise the construction of a massive structure over the Green River. He planned to support the tracks and all trains over this bridge by constructing an elaborate trusswork of his own design supported by four enormous and intricately detailed stone piers. John W. Key of Woodsonville and his two sons, Abner David Lewis Key and John Martin Key, all stonemasons, were hired to construct the piers.

Bridges are employed to support weight over an open space, and transfer this weight to their supports, or abutments. They may be fundamentally classified by the reactions they exert upon their abutments. They may push on the abutments, pull on them, or simply rest on the abutments without horizontal forces. In general, the production of horzontal forces in the bridge structure is the cost of transferring the weight of bridge and load to the abutments. Bridges are generally, and less fundamentally, classified by the type of construction. Arch bridges push on their abutments, suspension bridges pull on them, while beams and trusses rest on their abutments without horizontal forces. The term beam is used when the material of the bridge is in a single piece, such as a log or a plate girder, while a truss is built up of pieces, called members. A truss generally has an upper chord in compression, a lower chord in tension, and web members consisting of diagonal or vertical ties (if in tension) or posts (if in compression).

Othmar Herrmann Ammann. Swiss-American engineer and designer of the largest bridges of the city of New York. Born on 26 March 1879 in Feuerthalen bei Schaffhausen, Zurich, Switzerland. Deceased on 22 September 1965 in Rye, New York, USA. Associated with the following firms:Formerly: Triborough Bridge Authority. Technical director(s), Port of New York Authority. Founder(s), Ammann & Whitney.

THE FIRST BRIDGE (1884): As early as 1874, residents and business owners petitioned officials in New York City and Westchester County (which governed the Bronx at the time) for a Harlem River bridge at 138th Street. After three years of studying not only the location of the bridge, but also what type of bridge should be built (whether a high fixed bridge or low moveable bridge), the New York City Parks Department, which at the time had jurisdiction over all bridges in the city, received a $100,000 appropriation from the Board of Estimate in 1878.
Between 1879 and 1881, engineer Alfred P. Boller and General John Newton prepared plans for the Madison Avenue Bridge. This planning was done in the context of improving navigation along the Harlem River. During this time, the New York City Parks Department put out various bids for constructing the bridge, which was estimated to cost $510,000.

Against the city's gleaming spires,

Above the ships that ply the stream,

A bridge of haunting beauty stands –

Fulfillment of an artist's dream.

Welcome to the Portland Bridges page, presented by Environmental Services, Oregon Department of Transportation. The bridges of Portland, Oregon are numerous and diverse. The structures, ranging in age from 27 years to 90 years of age, represent a variety of construction types including vertical lift spans, double-leaf Bascule drawspans, and the longest tied arch span in the world.

It was called the most beautiful bridge in the world. At the time of its 1931 opening, it certainly was the longest single span. To honor the engineering feat it represented, a stamp with its picture was issued, and the bridge became the subject of music, even a children's book.

Yet, a section of suspension cable for the George Washington Bridge in the collections of the National Museum of American History can only hint at such glories. Three feet in diameter and ten feet long, the massive cylinder weighs an ungainly 34,000 pounds. From its ends protrude 26,474 individual steel wires, compacted under 400 tons of pressure. Before computers, this experimental section helped engineers model the effects of compression on the finished bridge's cables. Today, it represents an engineering marvel, whose creation spanned half a century of depressions, politics and the passions of two of America's greatest bridge designers.

John Job Crew Bradfield was born in Sandgate, Queensland on the 26 December 1867; the son of John Edward Bradfield and Maria Crew.

He received the first part of his education at Ipswich State School and Ipswich Grammar School. Bradfield was the winner of the three exhibitions given each year by the Queensland government, which enabled him to study at Sydney University. He graduated as a Bachelor of Engineering in 1889.

Eleven major bridges unite New York City together and with the rest of the nation. One engineer was responsible for more than half of them, yet hardly anyone knows his name.

Othmar Ammann came to America as a graduate of Swiss engineering schools and learned bridge building from the reigning bridge engineer, Gustav Lindenthal. As his protégé, Ammann worked on the Hell Gate Railroad Bridge, an arch bridge of unprecedented strength and beauty. Lindenthal had plans for an enormous rail bridge across the Hudson River, but they were rejected as too expensive. Ammann proposed a lighter, less expensive span for automobiles and trucks. In a painful parting, he left Lindenthal and built the landmark George Washington Bridge, a span twice as long as any suspension bridge in the world.

Civil engineer.
Born: 26 December 1867 Sandgate, Queensland, Australia. Died: 23 September 1943 Gordeon, New South Wales, Australia.
John Job C. Bradfield was associated with a great range of engineering works including the Cataract and Burrinjuck Dams, the Sydney Underground Railways and Brisbane's Story Bridge. He was, however, best known as one of the original designers of the Sydney Harbour Bridge. For his thesis on the design and construction of the Sydney Harbour Bridge and the city railway system, Bradfield was awarded the degree of Doctor