The daily journal. (Salem, Or.) 1899-1903, 1903-10-21
Chicago Sky-ScraperS
That Are Built on
Rats
Impossible to y Reach Bed
Rock, A Bed of Clay over
Plastic Mud Supports
Them

diihltt1N Aut blhel udgt thdb niOutiu
architecture is huge paradox? The
heaviest and tallest buildings are
really houses built upon sand--or
the mud as the case may be-"
Then how do they stand?" he was
asked.
"oh they are safe enough Take
the Park Row Building in New York
II is the tallest commercial structure
in the world, and probably the heav.
lest also. II weighs over $4,000 tons,
which means a pressure OF nearly
5000 pounds on each square foot of
the site. II 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 hundred feet
deep.
1T Is perfectly safe Nearly 1000
large piles were driven in II by
2,O0O-pound hammer falling 20 feet,
which compacted II until even these
tremendous blows could force them
no further. and they could carry their
loads OF $4,000 pounds each. Groups
OF these piles we're capped with con.
crete and pyramidal brick tiers were
built on that. Steel beams we're laid
on the fiat tier tops to distribute the
loads over the surface OF the masonry
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 the sand or mud to the solid
rock.
In other cases heavy buildings are
supported on piles which neither reach
10 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 steam hammer
II they are driven there thirty or
fifty feet and left undlsturbed a few
hours. II Is found that the adhesion OF
the tenacious mud Is 30 great that
that they can hardly be started again,
and may be safely trusted 10 carry
heavy permanent loads. which are
really supported by the sickness OF
the mud
The ST. Paul Building In New
York is supported on very deep bed
OF fine wet sand which was only ex.
cavated 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 found |
ations, consisting OF crossed layers OF
steel beams and girders.
"The spreckles Building In San |
Francisco which weighs over $4,000, |
600 pounds, rests on dense wet sand
ON which a solid platform OF steel and |
artificial stone was laid as foun
dation This building has passed un
injured through the test OF severe I
earthquake shock
In another big building the col |
umns are seated ON inverted arches,
which distribute their loads over an
the space between them, The arches
are laid on long, wide concrete foot
ings, which reduce the unit pressure
sufficiently Tor the fine wet sand on
which they are built.
Few II any, tal buildings are ON
worse soil than those OF Chicago
Here. only ten or hfteen feet below
the surface, Is a crust OF clay not
more than ten feet thick, which floats
ON wet plastlc mud from sixty 20 100
feet deep. Piles moro than 100 feet
long would be required to reach the
hard pan or bed rock. and most OF
the tall buildings Thew really stand ON
great RATS built on the surface OF the
clay Il has been found that load OF
5000 pounds per square foot OF clay
surface viii settle slowly for several
months After settling perhaps two
inches IL will become stationary, and
may be considerably increased with
safety,
Very often buildings are dellher
atoly started above grade. and Il Is
reokoned that they viii sink SO many
inches"
Huge structures built ON such (
foundations are perfectly safe" the Z
architect continued. Almost any 1
soft soil can be successfully conquered {
nowadays by an architect who knows I
hia business. We Americans are not &
ne only people Who build ON the Q
'aRd. The native architects Of india 3