, 1875-05-09

AUes. luo t0nd4ALonA OF u1Qbk u Sao QWe1uDEt
On tbeae streets vera built On this, and notably
the original Second Presbyterian Church This
surface beach e2nd has always proved to ho 4
reliable bod for foundations. But ne have moth
ing to do With the two aforementioned stratn in
| this discussion.
To return then.
THE UPPER STRATUM
Of clay Was determined to be sufficient for the
| foundations OF the new building in accordance
with the best experiences Of Chicago architects,
notwithstanding the feet Of tho underlying
vegetable mater s1 which, b.tresn n
this and the blue or "tunnelH clay. When the
plans were nlsle for the foundations in tta
manner that have mentioned above, they we're
On such IA extensive scale, SO broad and mas
sire th.t the square interstiees thus left were
so small compared with tho whole surface az
to be comparatively insignificant. It YVES esti-
mated that it wcu1d be no more expensive to
Tuu the concrete over tns whole site. The
natural wetuess Of the site nas another gtxoue
argument in favor OF this course. Us by covering
the whole ground great trouble would be
avoided, aud it would be necessary to pump
out tho raiu-water during the progross OF the
building. It uas accordingly concluded to rrr
tho concrete fees II thickness over ths whols
lot. This has been done, and On thia plataaz
the building now stands.
But the moment this plan was carried out
THE ooSoRETE ck1sED TO Be FOUNDATION,
properly speaking. It became An artificial
plateau BY itself, aud the foundation proper
commenced on top Of it. And it il. just 80 much
set.e1 tnan "4ss was &nere Dolo1o IN proportion
~ ~ ~ ao 'oocn Eafoef. IN ti.!s tho scientific
coosssuetof woaio commence his bullding 3uss
~ he would on hard ciay OF sand bottom.
Whethor such is tho caBe or not am not suf-
ncaently ACQUAINTED with the building IN detail
" say" Nut y IL perfectly clear that building
u u great "easne can os erected On such bottom
Esen Esuppos!ng Pc .nat taera Is very soft mate
below hat
Aaces OF tho 1ochngs IN detail are exactiY pro-
poluonoo 70 sne weight they arc to carfy,-so
many tons TO the loot everywhere, and exactly
~ tne same pFopo1uon In al parts. building
tnas CONSTRUCTED may 60 on Setting, but 1t will
60 ALTOGETHER. II Is D. stubborn fact
1nas the ground is soft, and
IN unresstlns. soil cannot bo reachsd
'F any practicable means, the structure must so
down. Ii tho contractor knows bis business no
must carrJ cut the fundamental principle III
building foundatlous, proportion the weight to
the renaissance, and ho doaa ell that human
knowledge can devise, ind I'll chat il worth do
Ing under tho circumstances.
In the preeent case the borings allowed that
the site wrs practically an even one, that is !;
thara aro no hard places to co.nplcate tho prob
lem The ground must yield evenly il the
xelehts are equal This may bo poaaihle With
the building as designed or it may not, Much
depends upon wnethor or not It Is practicable to
increase or diminish the weights to suit the
out cascging the design, then the design must
oe changed It ia possible that portcoea or
colonnedas which do not GRITTY walls may have to
be omitted. or Il possible cat loose from tho
main building. But TO do so would bo to mako
;s1y ,oaossa nssa6saGt change with what
he:o to sssnae tue sudn % dso7s PICS 70 'se Sc:
Wnat tho bottom nos! The archives Of the oflca
OF the Supervising Architect would hare shown
{AY xk&eIA
and wonld hare iven them zs . result sections
Of the ground % teet deep. Still they drove
piles with 0o0-pound ranomer, and because
their pl1ea did not roach tao blue tunnel clay
suppose they went OF with report no bottom
bore. Our C1ty Engtneer could havo told them
that they could drive piles anywhere under our
heaviest buildings, which stand firmly and 80
curely, and still could not touch bottom II 1ess
than 50 feet
BID THEY EXAMINE 7n8 cosonzrE
teSta- ] had tho privilege Of
learning the results OF III these experiments as
to the composition and method Of making tho
Cement, md know Of no man more competont
Tor thls work than Piulo Warner, tho late fore-
ms .aa a indebted .e Mr Ranta
Festleasons for many valuable suggestions
would not a1ude to this except to add By way Of
!!luscatlon that IN reconstIucsin8 the founoa-
lions under the American Express Building
LOAU"C4 klo lA0eAO0 u 44AAhA4S EoAG1&tH NJ A0e
Government building, and have put It to the
segerast practicable test. I will give tho statis-
lies OF the largest pier OF tho front wall, BY way
II illustration. This pier has an average hoight
II LIS fest, and the wall is eH feet thick on an
average. Tho weight Of the pier, by eomputa-
ion, In zig tons, and t!1e aizs ct tho
>oncreta foundation is 8 BY Is feet,
giving . surface OF 1O4 fest, with q |
Eaight OF very nearly tons par superficial foot.
l'h's foundation rests u the aane stratum Of |
'lay A. that q the Government building, and Is
Is ID 1o1 wall II connection with Waila already |
aullt. The settlement has not exeeeklsd half an
nch- consider this c!ay capable to carry 3H !
ons to the square foot With whiah weight ths
attiemens would oe about inch In an $50
etod building II Is not Q difficult matter TO pro
nee 1si Tor ;,. . settlement en- q o.. .nen~
!! !aey nase tota Gown me pu1oines ana oner
aee1 t W. no ~ + enas i;s,t ~ 81
sro va, .aSn+o ~ ~ 49, aa' raao ~
.;nbt .dd,,ns ,ns+tsr sra T,,,ae ;11,atr,- /
rs ~ tha ne.,,rs >0A ~ '44o. o,,r "a;1
~ ~ 1nstho;3a ttat bass hsan'
av;aad ~ orarcnnna tI,a d;f;c7,tiss nocnoctnd
~. h;ts;,,1. ~, = j.; -shich th;n r-~o-,,J ba
,,s+.1,ed t4 ,nos, - nnr .h5oat .rct;tacte H y;
hia anac;o,ty Throno;, tho cor,rtesv ~ tioaa
oretafors eonnaetod With the bniidine lave