The Charlotte Democrat., 1874-07-20
THE Great Bridge Of the World

By the completion of the great bridge
across the. Mississippi, at st. Louis, The :
United States can claim the honor of thav-s'
ing designed and constructed the greatest.
bridge structure of the world, and compaE.
ed with which all others sink into compara-
tive insigniticance. 1t spans the river from
East ST. Louis, with three great arches,
measuring In all 1923 feet, the Longest
5 l5 feet in the clear. This immense. arch
is constructed with what is known as the
"double rib" enabling it to preserve its
shape under all circumstances OF unequal
pressure, and obviating the necessity of
spandrel bracing. The rests for the spans
are solid piers of granite and concrete, sunk
firmly in the bedrock of the river There
are two roadways, one above the other, the
upper being adapted for carriages and
pedesttians,4 aatlvtbe lower for railroad
trains. The top roadway is ffty feet wides
divided into two foot-paths, each eight feet
wide, aud a carriage road of thnty-iour
teet. The railway passages each measure
thirteen and half feet in the clear, and
are sixteen feet high, extending through
arched openings of the same. size in the
piers and abutments. AT each end of the
bridge trains are carried over the streets
and levces on brick and stone arches, and
on the St. Louis side they are conducted
into a tunnel, over which the carriagewaY
is run on level. The tunnel extends nm
der the street to Union depot, at some dis
tance from the river. On the Illinois side
the trains descend by a grade of one foot
in every hundred for three thousand feet.
where they reach the regular level of the
tracks. The lowest arch of the bridge il
fifty feet above the high water mark, and
the height from the water level to the up
per roadway is nearly a hundred feet. The
tallest mast on the Mississippi has not
reach enough to brush the cobwebs from
the arches The arches are composed OF
four series of tubes, starting from ponder
Gus skewbacks in the solid masonry Of the
piers. These tremendous buttresses against
which the arches rest, are secured. by cast
steel bolts, which pass twenty-eight feet
through the solid masonry. They are each
ten inches in diameter, and are therefore
strong enough to bear any possible straiGa
to which they can be subjected. There
are two series of these arch tubes springing
from the arch at distance Of twelve feet
one above the other, thus making the arch
twelve feet deep. Thus from each pier the
arch springs out with eight cast steel tubes.
each eighteen inches i'll diameter. These
are strengthened and firmly united by pom
derous truss bars of vertical supporters of
steel extending from the lower to the up
per chords of the arch, adjusted in snch a
manner as to secure the equal distribution
Of the weight of the bridge and the load il
may carry. BY this arrangement of the
tubes each railway track will in fact be
supported by four Of these ponderous
chords OF crucibe. cast steel. The cost of.
the structure, with its approaches, was
about eleven millions of dollars. ....s.s .ts.
| The famous Waterloo bridge across the
Thames measures but 1880 feet total
length, with nine arches each of 100 feet
! span and 80 feet in height. The new Lon
don bridge, though an elegant structure
and much praised for It's architectural beau
/ Itv, has but few feet more of span than
the Waterloo bridge. The Southwark
iron bridge, also across the Thames, which
at the time of its construction few years
ago was called the finest metal bridge in
the world, has three arches, like the ST.
Louis bridge, the longest or middle arch
measuring only $40 feet, with height OF
] "a feet. Other bridges in our own coun-
try, notably the St.-Lawrenee bridges, the
new bridge at Omaha, and the great
bridges of the Ohio and the Hudson. are of
small account in size by comparison with
this St. Louis monster. The prospective
East River bridge is out of the catalogue,
belonging to the order of suspension
bridges, of WHICH it promises to be par exc
cellence the chief. OF this order American
bridge builders claim two other of the most
celebrated structures in the world, that Of
Niagara Falls and at Cincinnati. The
largest suspension bridge in Great Britain
is that over the Menai Strait In North
Wales. The total span of this enormous
structure is $50 feet, only As feet longer
than the middle arch of the pride of st,
Louis.-BaLti1sore american. =
IRON RUsT.-To remove iron rust from