Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-08-19
TO-DAY TO SETTLEIT.
Everything in Readiness for the Great
Engineering Feat
NOT EVEN A HITCH is EXPECTED.
Details Of Erection and Floating of the
Great Channel Span.
THE INTENSE INTEREST IN THE WORK

sion promoters, one-half the population o.
the city is expected to visit the Ohio con.
Meeting bridge this afternoon, and witness
one Of the most novel and interesting engi.
neering feats of modern times. This will con,
sist in placing in position the northeast
channel msiu span.
The construction of this connecting span
was completed in the incredibly short period
of Is working days; the first pieces OF work
being placed in position on the Sth of July,
and the last rivet driven home on the 26th oi
the same month"; few wet days interfering
with the progress. Previously, on a series Of
piles rising about Is feet out of water, and
extending along, and at distance of about
30 yards from the northeast side of Brunot's
Island, substantial framing of false work
had been erected. This false work is about
$40 feet long, "a feet high, drawing
in from a width of 90 feet at the
base to about 80 feet at the top. 1t consists
Of trestles, each having five posts, strongly
bolted to cross-beams and skillfully and
securely wrought into one piece of compact
framing by means Of longitudinal and dag
onal struts of both wood and iron.
GREAT CARE TAKEN.
Particular pains were paid to having the
piling as level as possible, and for a pur-
pose afterward to be described, rows of 20
inch I-beams were used as a ground work
on which the false work was built. In driv-
ing the piling and preparing for the erec-
ton of this false work, provision was made
for the subsequent placing in position of
barges on which the bridge was to be foated
to its permanent location.
For some days past preparations have
been under way for the final and important
step. Nine ordinary coal barges had been
ordered from Messrs. Collins & Darrah, OF
Nebraska, and these were foated down and
held in readiness. They had not been
specially constructed, but with the view of
minimizing all chances of accident, the en-
gineers thought it best to have new boats.
Their dimensions are 190 feet long, 25 feet
wide and feet deep. In addition to the
ordinary bulkheads, fore and aft, three
more were constructed to obviate either end
of the barge becoming depressed through a
rush of water to that end, under unequal
strain from the weight the barge would have
to carry. Three tugs made their appearance
on the scene; a couple of decked barges
were floating near by, and everything was
in readiness for completion of the final
preparations.
These were brought to a head yesterday
morning. Each barge as it was brought
into place was sunkeu to the gunwale by
means of an influx of water introduced
through plug holes in each compartment,
and foated transversely between the piles,
occupying positions about 20 feet apart.
Additional strengthening timbers were in
troduced and the false work thoroughly Sc
cured to the barges. This successfully &C.
complished, the tugs we're brought into
requisition. Lines of piping, communicat-
ing with each of the barges, were brought
into play in connection with the pumps on
the tugs. with the object of clearing the
barges of water.
HOW THE SHIFT WAS MADE.
Slowly the water was raised from the
boats, and as slowly the entire weight of
the false work and the bridge on top of it
was transferred from the platform of piles
to the barges. As the barges lightened they
rose slowly above water, until their dis
placement became heavier than the weight
they sustained, and then the heavy mass of
wood and iron-work slowly left the place of
its birth on the piles and hoated on the
bosom of the river.
The pumping was continued until the
barges were dry, and then about 1000 tons
of dead weight had been raised about q
inches, supported evenly along its length by
the I-beams, which ran from end to end of
the structure. The feat was a thorough sue
cess, and was accomplished in about five
hours.
A decked barge was next secured at each
end of the line of barges, and securely
fastened thereto with heavy chains. Each
decked barge had two winding engines;
one, a 6-spool engine, and a double
friction drum engine, and the other
a 6-spool and 4spool engine. From these
seven 11h-inch and two Pinch hawsers were
run to the opposite shore and securely fast
ened, ard with these preparations accom-
plished the connecting span of the bridge
was ready to be foated into its final resting
place.
As the structure stood last night it was
155 feet above the water line, the bottom
CT ord of the bridge being about SO feet
above the water line. The barges drew
feet 9 inches of water. The weight sup
ported by each barge would be equal to
strain OF about ITO tons.
The northeast main channel span is of the
csmel-back design. 1t is 523 feet and half
an inch In length from center to center of
end pins, and 25 feet in width from center
to center of trusses. In height it measures
48 feet from center OF top to center of bottom
ch ord at the ends and 65 feet at the center.
NEARLY ALL OF STEEL.
With the exception of struts, which are of
iron, the entire structure is of steel 1t is
designed for a single track road. The floor
beams are partly suspended and partly
riveted between the posts. The stringers
are feet inches apart between the floor
beams, and riveted.
The weight of the span is about 900 tons.
It is designed to Withstand a wind pressure
of 40 pounds to the square foot and
strain of the weight of two full-powered
and train load exercising a
pressure of 1000 pounds to the lineal foot.
The work has been executed by the Key
stone Bridge Company, under the direction
Of Chief Engineer C. L. Strobel G. E.
George r. Buchan, Superintendent of Out
side Construction has had charge of the
work, assisted by Joseph Buchan, Thomas
Campbell, John w. PRIZE, and AL. Cline,
ioremen of the four gangs working on the
A score or more prominent railroad
officials, bridge builders, engineers, etc.. ar
rived in the city yesterday and last evening
to witness "the float" The Union station
yard was packed with private cars that had
carried officials into the city, and more are
expected this morning. Among those who
arrived were: Charles E. Pugh, General
Manager Pennsylvania Railroad. Phila-
delphla; T. L. Sheppard, Superin-
tendent Of Motive Power. Altoona;
J ames 2. Richards, Assistant Chief En-
gineer, Philadelphia; d. M. Snyder, AL
toona; E. B. Walton, Philadelphia; A. c.
Shand, Altoona; Job Abbott, a well-known
engineer of New York; j. +. Miller, Cen
sral Superintendent Pennsylvania Com
pany; F. g. Darlington, Superintendent.
indianapolis; Edgar Watts, of the Watts