The daily dispatch. [volume] (Richmond [Va.]) 1850-1884, 1883-06-24
A Novel Bridge M Niagara.

The Toronto (Canada) Globe. in a recent
issue, says: The Canada Southern Rail-
way bridge over Niagara river i TO be
built nj a point about three hundred feet
above the present suspension bridge. The
contractors have engaged, under very
heavy penalty, To complete the whole work
by the lst OF December ncxt--abOut eight
months from the time OF beginning opera
tons. The time occupied in building
the suspension bridge was three years.
comparison Will give an idea OF the
vast progress made in recent years i'm the
art OF bridge-building. The new struc-
ture will embody new principle never
before illustrated by any large work ac-
tually finished. Two similar bridges. how
ever, are now being constructed--one the
new Tay bridge over the Frith-Of-Forth.
Scotland, and the second for the Canadian
Pacific railway over the Fraser river, Bri-
fish Columbia. Bridges built after the
new design are known as cantileycr
bridges. Each end is made poi n section
extending from the shore nearly halfway
over tae chasm. Each section l. support
ed about IFS centre by strong tower. The
outer arm having no support, and being
subject like the other to thc weight OF
trains, a counter advantage is given 10y the
shorc-arm being anchored or weighted
This style OF bridge has been adopted 30
n 10 avoid the very great expense involved
in the construction OF a suspension bridge.
The towers on either side will rise from
the waters edge. Between them viii be
clear span Of 500 feet over the river. the
longest double-track truss-span in the
world. The shore-arm OF each cantioycr
having been bulls and anchored. the other
arm will be constructed in sections OF
twenty-five feet, the whole being made
seli-sustaining rs each section is added.
The ends Of the canticycr will reach only
37j feet beyond the towers, leaving
zap Of 12j feet 10 be filed. The link will
he supplied by an ordinary truss bridge,
which will be swung into place and rested
on the ends OF the cantileyeTs. Here pro-
viSion will De made for expansion and con-
traction by allowing play between the ends
Of the truss bridge and OF the cantilcvcrs.
At the same time the bridge will be thor
oughly braced 80 as TO prevent danger from
the lateral pressure Of the wind. The
''wayc" motion perceptlble on 4 Suspcn-
sion bridge win not be felt OF the new
structure. The total length of the bridge
will be S9j feet. II will have double
track and will be strong enough TO bear
two Of the heaviest freight trains extend
ing the entire length Of the structure. and
under side pressure OF wind at seventy
five miles per hour, and even then il * 70
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 intended TO
be used for excavations. but The f0unda-
tons VIII be in the large boulders that
have dropped from the elf during the past
ages, the crcyces being filled in with ce-
ment, making solid foundation. The
pressure will be 80 divided that upon the
foundation rocks it will he only - pounds
per square inch. The top Of the stone
structures will be 30 feet above The water
level, and from these the steel towers sup
noriing the cantileycrs viii rise $50 feet.
From the tower foundations mp the whole
bridge will be Of steel, every inch OF which
will be subject To the most rigid tests from
the time il leaves the ore 10 the time il en-
tiers the structure.