Evening journal., 1891-12-21
NORTH RIVERS BRIDGE.
Engineer Balet's Plans for the
Monster Structure.
TIE GREATEST OF THIS CENTURY.

II u 20 DO an Eight Track AFFAIR. Capa-
bile Of Sustaining Weight of IA, 400
Tons-compared with the big Bridge
IN seotinnd-Its width 100 Feet.
New York, Dec. 21.--Plans Of the much
TALKED Of new steel bridge, which, with its
| connections, is intended to run from some
where in the neighborhood OF Thirty-third
street and Broadway up to Eightieth street
| and then across to New Jersey, have been
handed by Civil Engineer Joseph W. Ballet
to Secretary Charles H. Swan, Of the New
York and New Jersey Bridge company. Mr.
Swan told Mr.. Ballet that the plan would be
referred to the board Of directors and to the
chief engineer The board, be said, were
anxious to decide upon plan suitable to the
war department
Greatest Bridge Of the Century.
Mr. Balet's plan is a very ingenious one.
and if adopted would certainly prove the
greatest bridge building venture Of the CEN
fury 1t provides for structure Of solid
steel 100 feet above high water, supported
with combination Of cables and canti-
levers. It is in this combination that Mr..
Ballet claims originality for his plan, and in
the course Of alengthy specification to the
company he nearly expresses the opinion
that the North river cannot be crossed by
eight tracks and at sufficient altitude on the
dead level on any other system.
Cables Alone Impraoticabio.
1.-THE suspension cable as developed tin
now says Mr.. Ballet, ''oifers, notwithstand-
ing its efficiency as a supporter Of heavy
loads over large openings, an obstacle which.
especially for this bridge intended for heavy
railroad traffic, which means concentrated
heavy loads, would make its adaptation a
matter Of serious reflection. A cantileyer
bridge win answer the purpose. but to give
an idea what win be the weight of a can't
lever l Defer to the Firth or Forth bridge.
Compared with the Scotch Bridge.
Your bridge is $50 feet long and has
eight tracks. The Forth bridge is q, 400 feet
long, with TWO tracks, and for its construc-
ton A, 900 tons of steel has been used. That
gives 3.S tons per foot per track, or 76 tons
per foot for two tracks, and with these hg-
ures it does not require much explanation "a
prove that the Hudson river bridge cannot
DO constructed as cantilever with two
tons of steel per foot per track But taking
two tons as a possibility the bridge would
weigh 1850 tons, which is more than twice
the weight required for my system. In my
construction l unite the efficiency Of the
suspension cable with the rigidity of the
cantilever BRIDGE
Strength Of the Structure.
& The plan shown indicates that the bridge
Is IN no respects an unsightly structure The
cantilevers are supported on three piers in
rir A A.
cables running from one to the other. giving
the idea Of equal proportion The details Of
strength and size Of the proposed bridge and
the distance between the piers are interest
ing. Mr.. Ballet says. "The openings are
wide, beginning from New York 600 feet.
/ LOO feet l,150 and 500 feet The bridge Il
100 feet wide, has eight tracks and is com
posed Of five girders and eight suspension
cables, and the whole so constructed as to
be able to carry load Of IA, 400 tons, which
viii never be upon it at the same time.
Weight OF the Cables and Girders
in addition to this it has an extra sys-
tenn Of girders to withstand the widest hur-
ricane. The cables are composed of 3,721
steel wires of 3-l0 inch diameter OF these
8, i2l wires 1872 are necessary to Withstand
the extra strain to which the cables are sub
Jected to in very cold weather The re-
naming wires are necessary to carry the
girders, roadbed, etc. The weight of the
eight cables is $500 tonR The weight Of
the girders is % 900 tons, in which is also o
surplus to take up the extra strain in very
hot weather. The average weight Of the
bridge per foot and per track is is seven
Fights Of a ton, or seven tons per foot for
eight tracks, and the total weight Is 80, $50
tons.