Evening star., 1934-08-28
BUILDINGS WEIGHT
ON EARTH STUDIED
Greatest Pressure Is Found
in Center OF Structures
Plot.

What happens to the ground UNDER
meath when Q big building Is erectedf
Accurate information on this problem
has been sought by engineers for
long time and now the essential In.
formation is available as the result
of the activities of a committee OF
the American Society of Civil Engi-
neers, working under a grant from
that society and the Engineering
Foundation.
This accurate information has up
set the old theory under which 1t was
believed that the strains were dis
tributed over an area much larger
than the base of the building. Now it
is know that the ground outside the
lines of the building bear practically
no part of the strain, and that the
center of the building area bears the
greatest strain of the burden with
rapidly diminishing portions distrib-
uted toward the edges.
Soil Structures Studied.
The information obtained by the
committee is of more than theoretical
interest as it will mean greater econ
omieS in the erection Of foundations
for buildings and will furnish a basis
for checking up the safety factor of
foundations previously erected for
large buildings. The work of the
committee embraces q much larger
scope than this, as it included the
study of the nature of soils and their
adaptability to support heavy build
ings. Some soils that look quite firm
become plastic under heavy strains
and flow under the weight of heavy
structures. Some times a soil that is
quite firm has under it, at a small
depth, plastic soil. Such soils will
not satisfactorily support big build
ings, and If one is put on any Of them
the building Is likely to sink or suffer
deformities.
A world-famous example of build
ing settling unevenly is the Leaning
Tower of Pisa in Italy. This building
started to settled unevenly while 1t
was being built and has continued to
settle ever since. That 1t started to
settle while in course of construction
some hundreds Of years ago Is indi-
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made to correct the slant of the upper
floors by building them higher on
the sinking side. Even these upper
floors on which correction was made
are now very much of level.
Committee Studies Tower.
The cause of the fitting of this
tower was investigated by one of the
members of the committee, Harry T.
zimmerman. He found it was due to
the nature of the upper strata Of soil
and the confirmation Of the lower
strata not far beneath. It would not
be difficult, using American methods.
to straighten the Leaning Tower and
make 1t safe for all time,
The members Of the committee are
Chairman Lazarus White, an engi-
neer of international reputation who
has devoted many years to the study
of foundations; Prof. George E. Beggs
of Princeton University, well known
for his work in analyzing stresses by
means Of models; Prof. M. L. Enger,
University Of Illinois, pioneer in the
science of soil mechanics; r. j. Fogg,
| formerly q professor at Lehigh and
now engaged in structural designs;
Prof. Glennon Gilboy, Massachusetts,
Institute Of Technology, authority on
soil mechanics; Harry T. zimmerman,
chief engineer Of Spencer, White 81
Prectice, contractors; Prof. Dimitry p.
Kynine of Yale, widely experienced
in European conditions; Frank A.
MarSton Of Metcalf q Eddy, Boston
engineers; George Paaswell, chief
engineer Of Joseph Meltzer, contrac-
tor, and Prof. Karl Terzaghi, author
ity on soil mechanics.
The committee will now give de-
tailed attention to the problem of
foundation piling.