New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1858-01-30
BRIDGING THE EAST RIVER.

The art of building bridges is not thought TO be
of the Oldest, mention is made of bridges in the
Bible; but it well mastered by the Romans, as
shown in the ruins still in existence. During the last
sixty years the plan of building arches of equal span
ard hight, for the purpose of making bridges level
has been generally introduced. The OF iron,
which led to the invention of suspension and tubular
bridges is equally modern, also the plan of building
bridges of such hight that rugged vessels Of any size
may sail under them.
The most remarkable specimen of n solid bridge for
railroad ears high above the water is the Britannia
tubular bridge, built by Stevenson over the Menai.
This strait was crossed by means of suspension
bridge the central arch OF which 500 feet span and
100 feet in hight, which Telford had built in eight
years. Stevenson erected close by his tubular bridge
in four years Calculation shows that could be de-
hected thirteen inches without injury and train
weighing 300 uns defects il only four enths of an inch
or about as much one hour OF sunshine does The
effect of the wind this structure of 900 tun is with
out danger.
Samuel Nowlan of this city, inventor OF the IRON
pavement, laid in Nassau street. and of some other less
practical Improvements is the designer of bridge for
crossing the East River in which the dimensions
adopted NJ the English engineer still enlarged upon,
and the most remarkable feature of which is, that
may be built without erecting center-rames equva
lent scaods. The bridge is intended to span the river
from the foot Vi Fulton street to the Brooklyn nights.
There are FIVE semi-elpc arches of five hundred feet
span. The arches spring from the piers one hundred
and eghty.ve feet above high water and they reach
fifteen feet higher at the CENTER leaving thus five
passages two hundred feet high and five hundred feet
wide for sailing vessels. The whole length OF the
bridge is two thousand five hundred feet the roadway
is one hundred fee, wide; each side are sidewalks
What remain. equally divided between double track
for railroad and an ordinary road for public
yeyances Of all kinds The bridge may be crossed in
all seasons BY cars in seven minutes The submarine
foundations of granite and octagonal the faces OPP
posed to the current form with il angle of So which
angie has been found best in the practice of fortfca
tons to repel balls without much injury 10 the struc
ue. 1t is consequently expected that vessel running
against of the piers would rebound any in the
stream without destroying the masonry, or being her
self STAYED In but, Sr more security, some yielding
woodwork, of tn. kind used at feryboat landings,
after the Fulton plan, would be Interposed. TIE
piers consist of number Of cae-con columns
resting the granite foundation, and bound to-
geher at erent nights. The arches also of cast
iIon They are made OF cast-iron vOussoirs, which
viewed from the side of the bridge resemble ordinary
stone youssOrs, but they differ much from them 10 this
respect that they bound together the strongest
instead Of being simply ju1taposed. This diff.
ference is made OF for dispensing with the enor.
cost of scahoiding. The building OF arches com.
mences by placing the first voussor Of each haf-srch
on tie pers then the second on the r and 80 on adj
vspcing over the water till all the hafarches 90 built
meet and form complete arches. Projections aud
responding cast in all the voussors that
in placing OF them a slsing motion has TO be given
TO make it hook with the one immediately below.
Wien in It's place hole in it comes in line
with Q similar hole in the other. Melted iron,
from portable furnace. is Immediately poured in
and the JOINT is perfected. The bridge abats on each
shore sgsins large building. The buildings are fire.
proof parallel the river OF the hight Of the bridge
and 80 feet il length. They do not interfere with
water privilege, beng built upon columns eighteen feet
in hight between which the passage is unobstructed
These buildings the edge of the water cover
ing only small portion Of the street. TIE roof of the
building the Brooklyn side is made Of ca.t-iron
pavement and is united by short cross-bridges with
street, which j. nearly Oh the same leyeD.