The morning call. [volume] (San Francisco [Calif.]) 1878-1895, 1892-05-13
A sPLENDID STRUCTURE.
One Of the Greatest Tliumphs of Mod
ern Engineering.

One Of the Greatest Tlfumphs of Mod
ern Engineering.
The great eantileyer bridge across the Mis-
sissippi River at Memphis, Tenn, which
was formally opened yesterday. lacks only
few feet of being three miles long and cost
nearly S3,O00,0O The approaches form no
insignificant part of the whole work. On
the Memphis side the track is first elevated
at Kansas avenue and is carried thence
along an embankment, across Delaware
avenue on steel girders 46 feet long, TO the
eastern abutment. distance Of almost eX-
actly half a mile, or to be precise, 2627.47
feet; while IN Arkansas the approach Is
still more gradual and difficult rendering
necessary a steel Viaduet 229065 feet long, a
tTestle 3O97.5 feet, an additional tTestle 10
cross the Little Rock and Memphis track OF
290 feet. and a final embankment Of Goa %
feet The viaduet, if erected independently,
would attract attention by reason OF Its
length and height. but il becomes almost IN
conspicuous when forming part OF greater
whole.
The superstructure is what woHld be pop
ularly spoken of as ''the bridge"-the tuU-
nel-like mass Of steel which carries the
tracks and roadway. rooted by huge chords
and guarded at the sides by tIusses and
stays and cOunter-stays. 1t consists Of sew
eral spans. The anchorage, which extends
from the Tennessee anchor to pier ], a distance
Of 22J63 feet; the cantileyer extending span,
thence TO pier IL, 1902 feet; the central,
supported by piers ii and III, 62106 feet in
length: 4 half-cantilever Of the same length
between piers III and ", and deckspan
Of 1886. Is feet covering the distance between
the last river pile and the Yiaduct tower,
firmly founded in the soil Of an Arkansas
village, but washed often and even now by
the errant waters of tile Mississippi.
The bridge is Of the cantlever type, though
~ w n G . 2 N rT-
cal specimen, for the central span Is
"single-trussed giTdeT." and forms the anchor
for a cannleYeT arm upon each side. The
short span at the western end is a deck,
the others are all through"
The piers are massive erections Of granite,
the total displacement being about 1900
cubic yards In building them the pneu-
matte eRisson was employed. Work was
actually commenced on October, 10, 1888.
on which day a load Of lumber was received.
1t was Immediately taken to the con-
tractors yards and the next morning men
were busily engaged in preparing the piles
and false work, and putting together the
caissOn.
The stone used was mainly the beautiful
gray granite of Georgia, though Indiana
limestone was employed also. RipraD for
the mattresses, and rough rock Tor various
purposes were found nearer home in Ten
nessee and Mississippi, while the cement
came from Kentucky and Maine.
Work upon the superstructure began on
April % 1891, and from that day TO the
present there has hardly been an idle hour.
The supeTstTueture is entirely of steel with
tile exception of the bolts, swiyels and
clevises, which are wrought iron, and the
wall pedestal plates, which are cast iron.
Also the bolster which surmOunts each pier,
and upon which the bridge proper rests, Is
partly iron. Over 1000 tons of steel were
used, and it assumed almost every conceiv-
able form, from 80-f0ot posts weighing 30
tons to ee-quarteT-inch Tiyets weighing
less than as many ounces.
The depth Of the water, the swiftness Of
the current. the great length Of the span,
and the shifting Of the river bottom were
the chief obstacles to be overcome. At
times the water was 20 feet deep. and the
piles used in the false work had TO be
stronger and larger than any ever required
in other operations of the kind. An idea of
their strength, and Of the soldity with
which they were planted" may be gath
cred from the fact that in pulling them
down a steel cable / inch and a half in
diameter broke several times, and force of
no less than 80 tons had 10 be exerted be-
fore anything would give way. The cur
rent also interfeTed with the caisson work,
rendering necessary the employment Of
anchors on both shores rs well as IN the
stream. The length Of the span Is feature
which will be appreciated better after cem-
parison with others. The intermediate
span. 100 AZ feet, is the longest Of its kind
in America by over 100 feet. the second be-
ing that across the Colorado River at Red
Rock, Cal, and only two in the world are
gTeater-the mOnstTous Forth In Scotland
and the Sukken in India.