Memphis & Arkansas Bridge, left
Frisco Bridge, center
Harahan Bridge, right
The Frisco Bridge, previously known as the Memphis Bridge, is a cantilevered through truss bridge carrying a rail line across the Mississippi River between West Memphis, Arkansas and Memphis, Tennessee.
Construction:
At the time of the Memphis bridge construction, it was a significant technological challenge and is considered to be chief engineer George S. Morison's crowning achievement. No other bridges had ever been attempted on the Lower Mississippi River.
The bridge is built entirely of open-hearth steel, a newly developed material at the time of construction. The structure features a 790-foot main span and two additional 600-foot spans. Its 65-foot height above the water was the highest clearance of any U.S. bridge of that era. The construction of the piers went nearly 100 feet below the water's surface.
Though some sources claim two cantilevered roadways were added to the bridge in the 1930's, one on each side, they probably confuse this bridge with the neighboring Harahan Bridge, which had two cantilevered roadways from 1917 until the Memphis & Arkansas Bridge opened in 1949. Today, the Harahan Bridge still has the metal remains of its cantilevered roadways; the Frisco Bridge does not. However, pedestrians, buggies, and some automobiles used the main deck of the Frisco Bridge before the Harahan Bridge opened (the bridge was closed to such traffic while a train was crossing).
Construction for the Kansas City, Fort Scott and Memphis Railway, later acquired by the "Frisco," began in 1888 and was completed May 12, 1892. In the end the project created a bridge that was the farthest south on the Mississippi River, featured the longest span in the United States and cost nearly 3 million dollars.
A testament to its design and construction, as of 2014 the bridge is still used by BNSF Railway. The bridge is listed as a Historic Civil Engineering Landmark.
George S. Morison:
George Shattuck Morison (December 19, 1842 – July 1, 1903) was trained to be a lawyer, but became an engineer and the leading bridge designer of his time.
History:
Born in New Bedford, Massachusetts, he was the son of John Hopkins Morison, a Unitarian minister. At age 14, he entered Phillips Exeter Academy and graduated by age 16. He went on to Harvard College where he received a Bachelor of Arts degree in 1863 when he was just 20. After a brief break he attended Harvard Law School where he would receive a Bachelor of Laws degree by 1866 and was admitted to the New York Bar. In 1867, with only general mathematics training and an aptitude for mechanics, he abandoned the practice of law and pursued a career as a civil engineer and builder of bridges. He would apprentice under the supervision of engineer Octave Chanute during the construction of the first bridge to cross the Missouri River, the swing-span Kansas City Bridge.
He is known for many steel truss bridges he designed, including several crossing the Missouri River, Ohio River and the Mississippi River. The 1892, Memphis Bridge is considered to be his crowning achievement, as it was the largest bridge he would design and the first bridge to span the difficult Lower Mississippi River.
Morison was a member of several important engineering committees, the most important of which was the Isthmus Canal Commission. He was instrumental in changing its recommended location from Nicaragua to Panama.
Union Pacific R. R. Bridge (1887) between Omaha, Nebraska and Council Bluffs, Iowa
The Memphis Bridge:
Source: wikipedia.com
