New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1907-03-03

tons, each section representing an enormous
caisson. According to a statement made by one
of the officers. there will be over - 900 900
pounds of concrete used in the building, 1.1OO.-
600 of which will be used in the floor arches
alone. 1t is said that the amount of concrete
going into the floor arches would be enough to
pave Broadway from curb to curb one foot thick
from the Battery to 42d street
Some idea Of the weight the great cofferdara
foundation is expected to sustain may be gained
from the statement that the structural ste-I
used in the building viii weigh over $4,000 toms.
and that the whole building, when completed.
viii have a theoretical living and dead load of
4OOO00O0O pounds. and will be the largest and
heaviest building in Manhattan.
Piling foundation for buildings has boon
and Is still used In many different forms. Ono
Of the most striking instances of the recent uso
Of wooden piles in this city was in connection
with the laying OF the foundation for the Long
Island City powerhouse Of the Pennsylvania
New York & Long Island Railroad, where tho
engineers Westinghouse, Church. Kerr & Co,
put down 900 wooden piles. These were driven
with a spacing on an average of , feet 4
inches between centres over the entire area
The piles. which were Of spruce. varied In
length from twenty-flv to forty feet and TIA
butts OF them covered with Il monoIithto
concrete cap which under the stacks or column
caps averaged about S feet inches in thick
ness
Concrete piles have come into favor in The
last few years In sinking these q steel jacket
or form is used This hollow form Of steel s
provided with a sharp point which Is divided
through the centre and so hinged either side
that although it will hold firmly together and
act as a unit when being driven into the earth
It viii open like the jaws OF an alligator vhan
il is withdrawn The object Of this arrange
Inent is that after the shaft has been driven
the desired depth and Its interior filed WITH
concrete the jacket may be withdrawn and thu
solid pile OF concrete left in position.
Not a few Of the most modern OF the down
town buildings in Manhattan rest on concrete
piles. The Produce Exchange Building, at
Broadway and Beaver street. Of tho
first buildings to be put up On such piles. and to
satisfy the Buildings Department Of the city az
the strength Of this form of foundation pile
was selected and loaded with test load OF
forty nine tons Under this test it showed no
Produce Exchange Building rests We're driven
thirty feet through quicksand to the firm gravel
beneath
To support the walls Of adjoining buildings
while the work on deep laid foundations is go
ing on contractors often resort TO odd methods
Perhaps the most surprising Of any Of those yet
employed in this city was that used by the
ORourke Engineering and Construction Com
pany when laying the foundations for the Nes
York Stock Exchange. The walls of one OF tho
adjoining buildings showed signs Of settling
the deeper excavation went down beside it Tho
contractors determined to take risks, and so
set about bracing it up with Of concrete
piers or overgrOWn concrete piles. Cutting away
under the wall in several places. small caiSsonz
We're started down toward bedrock Instead of
these with pig iron weights 81
usually done in caiSSon work. big jackScrewa
were lifted into place above them. These were
kept screwed up tight, and in this manner tho
building Was forced TO become its own pTs
driver. the weight OF the wall forcing the con
stantly growing concrete pier beneath II DOWN
@aId until il reached bedrock