The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1869-10-26
TIE EisT RIVER BRIDGE.

The Work Assuming shupc--The Caisson
for the Great Tower ON the BROOKLYN
Shore.
Yesterday the East River Bridge Company entered
Into contract with Messrs. Eel & Weob for the con.
structon OF The caisson upon which IL TO rest the
foundation OF the tower on tue Brooklyn shore The
cost OF the caisson will be 100000 aud weight OF
the structure not less than 5000 tons. MIR. VIII
liam q, Kingsley, OF the firm OF Kings
ley b Keeney, has been appointed by the
executive committee general superintendent Of
the work. The upper slip of the Fulton
Very Company is the location decided upon for the
central point Of the tower. Ii will extend 10 within
ten feet OF the second ferry sp, while the oppo
site end will encroach upon the coal yard OF Mars
ton Powers. The cost OF the change OF the bridge
viii be about 100000. Operations to be COM
menced at once. The woodwork at the old docks
and piers Will be torn up ana everything down TO
low water mark Will be removed. The bottom
OF the river viii be excavated 10 depth oi twenty
two feet below high tide. The space to he cleared
and ievelied Is ITO feet long by l02 leet extending
out into the river. Divers viii lie employed to re-
move the distractions at the bottou and bias tinR
will have TO be reSortcd to.
The caisson rs like a large scow, or nat-boitomed
boat, turned upside down. nothing more. Then, IL
maRines ts being sunk 10 the bottom OF the
on level space prepared for ~ mat the water Is
forced out OF The boat, "air C hamberu az IL is
called, by means OF compressed air; that workmen
are sent down into the chamber IN shaft cut
through tue top OF the CafsSon bottom OF the boat
VINO, with the AID OF calcium lights, dig out the
teria beneath them, which is hoisted up to the
world above; that they continue excavatIng until
the proper depth Is reached the casson SINKING,
and, OF course on perfect level az the WORK pro-
gresses, ana that the "air cnam5ern Is last OF all
MED up with cement, general idea can be formed
OF the way "a which The foundation OF the tower will
be laid.
EXPERIMENT. which have been made on the quick
SAND ped OF the East river while excavating dry
uock. prove lis bearing power 10 be ten ions per
square loot ~ MIR RoeDllnRs plan, 1t is proposed
70 rest upon this bed weight Of opiy four tons per
SQUARE asOt The weight OF each tower Is 20 be
somewhat over sefenty-ive tons.
10 oBl1pute tSa vast weight so tbst part OF
Inc pressure on the base snail be over four per
loot ~ mas been decided that the area Of the iounds
sion snail beiiI0 feet long by l02 feet broad This
rrea VIII be composed OF huge timbers resting on
the sand ana bearing the masonry work OF me tower
upon IT, The timber VIII be twenty feet tluek and
tins vast mass OF twenty feet by 10 by lol will be
securely boted into one solid fratue "a ia AZ tie
weight Of the tower above can never denect ID the
slightest degree at any point.
the Board unanimously hold that 800 feet hgl, OF
q masonry structure could be safely ana unyleld-
inaIy erected on such a timber foundation aa pra.
posed by Mr.. Hoeblng, and thai the superstructnre
thereon, properly built, would easily bear the
weight OF the bridge ant all the weight that could
DC put on the bridge.
gae bridge company have purchased about four