New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1862-08-12

81 fees Ia extreme breadth over all the bridge
VII he o2 fees there will DE foot path ut esch
slde sevs" feet wide, and broad central rad way
=. On the New-York side the abutmeut is finished.
IL work OF substantial masonry, faced with
grsnFe blocks At the left eide fight of broad
granite Steps eads to the river and similar Ai0hk
ID 10 De tSid on the right side This will msks the
water front ~ this bridge similar to the qaa,s on The
rivers In Europe where stone rt. ps lead IN ~ v.,.,
for the purpoec Of Entering email boats. Operations
have not been commenced on the north sbore of TIA
river, owing to come unsettled fieulty about the
land. The piers IN the river in Q very forward
state. The central one, for the turn.table OF the
draw consists Of eleven east iron columns each "a
feet IN diameter, sunk and arranged in clreIe Of
dfiy feet in diane In the center Of these u .
single column forming the axis Of the whole Tts
other two piers eech composed OF single row a
five columns, the three inside beae six feet in
diameter, and the outside eight tee ia diameter
each.
Only one column Of all these piers now remains 10
no suDk. The sinking and construction Of the pier
columns involve interesting engineering operations
A description of one will sufiice for the whole.
Each column is formed Of sections Of cast iron vary.
ing from nine to nine and halt feet in length, and
tive inches In tn ckness, and Cast with inside
fange for boiling them together like pipes. In com
Ineucing 10 siDk Of these three sections rse
boited together, forming column about ~ fee4
hiss. i! is set psrpendicularly upoa a strosg
wooden frame In the water, aud when placed over
where It has to be sunk the frame s removed with
derrick. and tie column lowered upon the river
bed. The other sections are afterward boiled on
Ii now requires To be sunk to q considerable deptA
below the bed Of the rver to obtain secure eunds-
tfoa. Some columns require to be sunk deeper usn
others. One has been sunk no less tbsn IS tees
seven inches below the surface OF the bottom.
In order TO effect this object, the column ia con-
vertsd Into diving bell, into which the operatives
descend ard sxesvate lDside, the column sinking a.
the work progresses, until the proper depth u
reached This depends on the nature Of the bottom
VI the river. The hight from bottom to top ranges
from 50 to 70 feet. In order to sint a colamn, .
large cylindrical air tight chamber, call an ar.
lock" IL fastened its top. hi, IL provided with
door on it, bottom and another on It's top; and
also with valves packed with iudia-rnbber. Ii u
charged with sir by a steam engine d .uated on .
scafold which operates several air pumps and forces
sir In, the lock, through flexible iute. As the
cir prsssure increases, the water which entered The
column In sinking is forced out underneath, unth
The bed Of toe river Is exposed. by the peculiar
Arrangement Of the valves and doors VI the airock,
the pressure OF air to keep out The water s uiais-
tanned oy the engine, in the column, while the
descend and excxvate below, aud seDd up tie dirt
through the interior until ths colnn has been saEk
to it's required depth. When this is oapilsned,
the column 10 filled up Inside wi masonry, 80 THAI
when finished it Ia . compound OF cast iron and
solia masonry. The sinking OF these hollow sha's
bas been work of great labor and difficulty, -
boaldsrs, wsg ing from one 10 thirty tons have 70
be removed to permit their descent
On the center pier great circular girder, forming
a ripq-cap 46I feet in diameter, feet broad and
fr.t . inches doep-has been lsid 1t is to form she
roadway of the draw turn table. Ths girder has
been st in eleven sections, and its top 10 now being
planed into position ny planer erected for the pur-
pose and winch ia the largest We have ever seen. lt
resembles q revolving crane, with the center shaft
in the middle column OF Tie per- The cutter travels
round the girder, piapng as IL moves. IL il driven
by betting from the s'eam-eDgine, aad the CATER ~
made 10 traverse round by plnion biting into rack
secured inside of sbe girder. The enter OF thn
plnsr travsrses circle of nearly 47 feet, nakpga
REVOLUTION every six minutes. A track Of smooth,
wronuht-iron blocks will be laid upon the face Of
this rrder this the old rollers Of the turn
tanIs of the draw will be supported and travel.
There will DO 90 hollow rollers on the tnrn-tablot
each Two feet In diameter, aud tie draw VIII be CONF
pOssd Of peculiar uipiet arched rfuer, wtn ~
axis in the central columns OF the circular pier In
position il will rect three piers: when open u
VIII be supported and moved on one. 10 al ow yes.
sells TO pass The mass Of he draw 10 be moved VIII
weigh about 400 tuns.: Ia b order Tor Tue spans
will be constructed Of half inch plate irou strength.
eued with angle iron. IL will be y nveted arcned
box 81 feet Deep feet broad, and set IN cast iroa
shoes and sustained by wrought ron Isnslo' n,,
no Loo. thu. 3! insheo in diameter. Earn span VIII
have two girders, and the flooring viii be laid ON
rolled ne die beams or f,or Orders one foot deep.
When the spans are erected, ornamental baius-
trades of cast-irvn will be put mp, AMI The whole
structure when finished according 10 the design,
will be beautiful as well substantial. Every pre-
caurio appears 10 be taken to obtain superior ~
well ms desirable bridge, by the employment If we'll
known, frst.oass men, who have charge Of the diff
ferent department, aud BY the Use of The very bSst
materials. The Chief Engineer is Mr Erastss ".
Suith; As,i t.nts, Ethan Rogers aud lheopAihs
Sickles. lie Superintendent W has had crnge
from the beginning OF the enterprise, Mr.. james
Hough; Mr.. Charles V. uough has charge Of tie
difficult work Of sinking the piers and completing
their masonry. Dr. John Roach OF ,hs city Is Con-
tractor.
When completed, this will be the first bridge in
the Northern States erected on cast-iron columns.