FOUNDATIONS OF THE CENTRAL VIADUCT OF CLEVELAND, O.


The Central viaduct, now under construction in the city of Cleveland,
is probably the longest structure of the kind devoted entirely to
street traffic. The superstructure is in two distinct portions,
separated by a point of high ground. The main portion, extending
across the river valley from Hill street to Jennings avenue, is 2,840
feet long on the floor line, including the river bridge, a swing 233
feet in length; the other portion, crossing Walworth run from Davidson
street to Abbey street, is 1,093 feet long. Add to these the earthwork
and masonry approaches, 1,415 feet long, and we have a total length of
5,348 feet. The width of roadway is 40 feet, sidewalks 8 feet each.
The elevation of the roadway above the water level at the river
crossing is 102 feet. The superstructure is of wrought iron, mainly
trapezoidal trusses, varying in length from 45 feet to 150 feet. The
river piers are of first-class masonry, on pile and timber foundations.
The other supports of the viaduct are wrought iron trestles on masonry
piers, resting on broad concrete foundations. The pressure on the
material beneath the concrete, which is plastic blue clay of varying
degrees of stiffness mixed with fine sand, is about one ton per square
foot.

The Cuyahoga valley, which the viaduct crosses from bluff to bluff, is
composed mainly of blue clay to a depth of over 150 feet below the
river level. No attempt is made to carry the foundation to the rock.
White oak piles from 50 to 60 feet in length and 10 inches in diameter
at small end are driven for the bridge piers either side of the river
bed, and these are cut off with a circular saw 18 feet below the