The times. (Owosso, Mich.) 1882-1897, 1883-09-07
The New NIAGARA Bridge,

The Canada Southern Railway bridge
over the Niagara river, is to be built at
a point about 800 feet above the present
suspension bridge. The contractors
have engaged, under heavy penalty,
to complete the whole work by the first
of December next, about eight months
from the time of beginning operations.
The time occupied in building the sus-
pension bridge was three years. A
comparison will give an idea of the vast
progress made in recent years in the art
of bodybuilding. The new structure
will embody n new principle never be-
fore illustrated by any large work act
ually finished. Two similar bridges, how.
ever, are now being constructed-one,
the new Tay bridge over the Firth OF
Forth, Scotland. and the second for the
Canada Pacific Railway, over the Fra
ser river, British Columbia. Bridges
built after the new design are known rs
cantilever bridges. Each end is made
up of section extending from the shore
nearly half way over the chasm. Each
section is supported about its center by
a strong tower. The outer arm having
no support, and being subject like the
other to the weight of trains, counter
advantage is given by the shore arm be-
ing anchored or weighted.
This style of bridge has been adopted
80 as to avoid the very great expense
involved in the construction of sus
pension bridge. The towers on either
side will rise from the waters edge
Between them will be clear span OF
500 feet over the river, the longest dou-
ble-track truss span in the world. The
shore arm of each cantilever having
been built and anchored, the other arm
will be constructed in sections of 20
feet, the whole being made self-sustain-
ing as each section is added. The ends
of the cantilevers will reach only 375
feet beyond the towers, having q gap OF
1875 feet to be filed. The link will be
supplied by an ordinary truss bridge,
which will be swung into place and
rested on the ends of the cantilevers.
Here provision will be made for expan-
sion and contraction by allowing play
between the ends of the truss bridge
and of the cantilevers. At the same
time the bridge will be thoroughly
braced so as to prevent danger from the
lateral pressure of the wind. The
''wave' motion perceptible on q sus-
pension bridge will not be felt on the
new structure. The total length of the
bridge will be 895 feet. 1t will have o.
double track, and will be strong enough
to bear two of the heaviest freight
trains extending the entire length of the
structure, and under a side pressure OF
wind rs miles per hour, and even then
it is to be strained to only one-fifth of
its ultimate strength.
The towers will not rest on bedrock,
as the rush of the river would sweep
away any caissons or other works in
tended to be used for excavations, but
the foundations will be in the large
boulders that have dropped from the
cliff during the past ages, the crevices
being filled in with cement, making
solid foundation. The pressure will be
so divided that upon the foundation
rocks it will be only % pounds per
square inch. The top of the stone
structures will be fifty feet above the
water level, and from these the steel
towers supporting the cantilevers will
rise 1870 feet From the tower founda-
tions up the whole bridge will be steel,
every inch of which will be subject to
the most rigid tests from the time it
leaves the ore to the time it enters the
structure.