The Savannah morning news., 1903-07-28
GREAT BUILDING ON SAND.
Worlds Heaviest Structures Stand
on shifting Soils.
From the Chicago Inter Ocean.

From the Chicago Inter Ocean.
DO you know" said a famous ar
chitect the other day, that modern
architecture is a huge paradox? The
heaviest and tallest buildings are real
ly houses built upon the sander the
mud, as the case may be-
"Rhen how do they stand?" he was
asked
"Oh they are safe enough. Take the
Park Row building in New York. 1t
is the taliest commercial structure in
the world, and probably the heaviest
also. 1t weighs over $4,000 tons,
which means a pressure of nearly g.
0G0 pounds on each square foot of the
site 1t is about a hundred times as
heavy a load as a good highway bridge
is designed to carry. And yet this
enormous load rests upon a bed of fine,
wet sand scarcely different from quick
sand and about a hundred feet deep.
1T is perfectly safe. Nearly 1900
large piles were driven in it by a O.
00-pound hammer falling twenty feet,
which compacted it until even these
tremendous blows could force them no
further, and they could well carry
their loads of 80, 900 pounds each.
Groups of these piles were capped with
concrete and pyramidal brick tires
were built on that Steel beams were
laid on the fiat pier tops to distribute
the loads over the surface of the ma
sonry. Some of the columns carry as
much as 100000 pounds each.
Many Of our heaviest buildings are
really supported on stilts-that is to
say, on foundation piles driven
through sand or mud on the solid rock.
I'm other cases heavy buildings are
supported on piles which never reach
to hard bottom nor are driven in firm
soil Long piles are driven into very
soft mud and silt, into which they sink
many feet by their own weight and by
light blows of a steam hammer. If
they are driven there thirty or fifty
feet and left undisturbed few hours,
ii is found that the adhesion of the te-
nacious mud is so great that they can
| hardly be started again. and may be
safely trusted to carry heavy perma-
men loads, which are really supported
by the sickness of the mud.
THE St. Paul building in New York
is supported on a very deep bed of fine
wet sand which was only eXcavated to
a depth of about thirty-two feet. A
one-foot layer Of concrete was spread
over the bottom of the pit, and on this
were set the real foundations, consist
ing of crossed layers of steel beams and
girders.
THE Spreckles building in San Fran
cisco, which weighs over 100000
pounds, rests on dense wet sand, on
which a solid platform of steel and
artificial stone was laid as a founda-
ton This building has passed un'n-
jured through the test of severe
earthquake shock.
I'm another big building the columns
are seated on inverted arches, which
distribute their loads over all the space
between them. The arches are laid on
long, wide concrete footings, which
reduce the unit pressure sufficiently
for the fine wet sand on which they
are built
Few. if any, tall buildings are on
worse soil than those in Chicago. Here,
only ten or fifteen below the surface,
is crust of clay not more than ten
feet thick, which float on wet plastic
mud from 60 to 100 feet deep. Piles
more than 100 feet long would be re-
uuired to reach the hard pan or bed
rock, and most of the tall buildings
there really stand on great RATS built
on the surface of the clay. 1t has
been found that load of 5000 pounds
per square foot of clay surface will set
tie slowly for several months. After
setting perhaps two inches it will be-
come stationary and may De conSid-
erably increased with safety. No at
tempt is made to prevent this settle
ment.
VERY often buildings are deliber-
ately started above grade, and it is
reckoned that they will sink so many
inches"
Huge structures built on such foun-
dations are perfectly safe" the archi-
tect continued. Almost any soft soil
can be successfully conquered now
adays by an architect who knows his
business. We Americans are not the
only people who build on the sand. The
native architects of India have done
so for centuries. sinking deep brick
walls into their soft, wet, alluvial soil
to serve as foundations"