Bridges of America - Pushing the Limits: New Adventures in Engineering - page 9

Bridges of America
America has more than half a million bridges, ranging from nondescript low-profile highway over-
passes to monumental works that raise our cars and spirits to great heights, but only a few of them
are known by name. Although just about everyone recognizes the Brooklyn Bridge and the Golden
Gate Bridge and can tell you something about them, only local residents, attentive tourists, and
bridge aficionados are likely to be aware of such structural jewels as Coos Bay Bridge, also known
as Conde B. McCullough Memorial Bridge, and to know that Conde McCullough is the name of
the structure's engineer and not that of a local Oregon politician. But whether or not bridges or their
engineers are well-known, masterpieces of bridge engineering are everywhere, legacies of their de-
signers' structural artwork that are as much a part of the American scene as are the red barns and
white churches of the countryside or the tall buildings and canyonlike streets of large cities.
From Maine to California, from Washington to Florida, there are bridges of note, and to each be-
longs a story that is at once unique and typical. Many bridges are truly one-of-a-kind construction
projects, and local constraints of topography, geology, traffic, politics, and economics make com-
plications commonplace. Across America over the past century, local idiosyncrasies have led to the
design and construction of bridges as odd and individual as many of their engineers. For example,
the 1928 structure that carries Maine's Route 24 the thousand or so feet between Bailey Island and
neighboring Orrs Island is supported over most of its length on a crib of large and heavy granite ties
that allows the tides to move freely in and out of the arm of Casco Bay that separates the islands. By
designing a masonry structure for this location, the state bridge engineer, Llewellyn N. Edwards,
obviated the problems of rot and corrosion that plague timber and steel bridges. Today, the Bailey
Island Bridge stands as solid as ever, a monument to the foresight of its designer, who in his later
years also looked backward to write a valuable history of early American bridges, thus preserving
memories of so many classic structures and their engineers.
In a park near Kansas City, a modest span of one hundred feet peaks forty feet in the air, thus
serving as a beacon for pedestrians looking to cross Rush Creek to a picnic area. The bridge was
originally built in 1898 to carry a line of the Quincy, Omaha & Kansas City Railroad, until it was
abandoned in 1930. It then stood unused for some years but after World War II was converted to
local highway use. When the filling of the reservoir behind nearby Smithfield Dam threatened to
submerge the bridge, it was disassembled in 1982 and its parts stored by the Army Corps of Engin-
eers. The reconstruction of the bridge five years later was spearheaded by George Hauck, a pro-
fessor of civil engineering at the Kansas City campus of the University of Missouri, who sought to
preserve it as a monument to its engineer, J. A. L. Waddell, who patented the A-frame truss in 1894
and built scores of such bridges in the Midwest and Japan.
The Canadian-born John Alexander Low Waddell received his civil-engineering degree in 1875
from Rensselaer Polytechnic Institute, the premier engineering school in America at the time. After
gaining experience with bridge-building companies and further study at McGill University, in 1882
Waddell accepted a faculty position at the Imperial University in Tokyo, which enabled him to re-