Omaha daily bee., 1909-03-15
GIANT TESTING MACHINE
United States Government Erecting
Largest One in the World.
WEIGHS TWO HUNDRED TONS
To Ne Used for TESTING strength OF
LarRe steel Beams aud CoIumhs,
stone and Concrete
structures.
Icon q SAD correspondentl

From z staff Correspondent
WARRINGTON. March 13-0specialJ
The. largest machine in the world for
testing the strength of structural ma
terisls used in great buildings and en-
gineering works is about TO be erected
by the United States government at The
geological survey testing station at Tltts-
burg, Pa. 1t win weigh more than zoo
tons and Will tower in the air to an ex-
treme height OF about eighty feet above
the foundations. II will exert a maxi
mum pressure of 10000. 900 pounds. which
is equivalent to placing a load of 5000
tons upon the beam or column to be
tested. "'t
This great machine will be housed in
a structure 100 feet in height and OF
unusuaf strength, to which the testing
apparatus will be secured by great rods,
in order 70 brace II against any sudden
pressure while the columns are under
going the strain upon them. Elevators
will run TO the top OF the machine so
that the ieXpsrts may examine the coll
umns SEEING tested from any point OF
view TO detect the first signs OF weak
enings ssy +.
when the ousbse bridge, collapsed with
great@loss OF life, general comment vas
made by engineers and others OF :he
lack OF knowledge concerning the strength
VI Hfbdt toiuHtHH uSeu III SuCn a SlTuC-
ture and q plea was made that a testing
machine OF sufficient strength he erected
so that the engineers may have accurate
data as 30 the amount OF load such a
bridge should carry With the constric-
ton Of this machine. IL will be possible
TO test, steel coluppns one-half the size
of the largest chords now used in any
bridge. This will be a decided gaIn TO
the engineering world, which has been
snxiously awaiting the construction Of
such a machine,
Primary RarRsse of Machine.
However, this Is not the primary purpose
OF this powerful testing apparatus. Joseph
A. Holmes. expert in charge of the tech
nologic branch, United States geological
survey, under whoseEgeneral direction the
Investigations are to be conducted, said to-
day; This machine was acquired for the
purpose OF testing the strength of large
blocks of stono, columns OF concrete and
brick used in the building and construction
work Of the government. The federal gov
ernment is the largest builder in the world
and 1t Is essential, IL the money is TO be
expended wisely that there be a complete
knowledge Of the strength OF the materials
used. The building and engineering con-
struetion work will require during the pres
ent ana the next, few years more than
s1o,OoO,0O per annum. It embraces the most
important far-reaching engineering
work undertaken by any government at any
time and also a program of public build
ingss costing from $A0oO.oOO to SIS, oOo,O 900
yearly. ''a "' "''
The testing IN this machine Of the stone,
concrete and brick columns will determine
the relative safety, 'adaptsbllity and dura-
bility of these materials, and how the
quantity OF each material used may be
safely diminished, thus reducing the cost
Of the construction work.
In the past it has been necessary to de-
termine the strength OF large columns on
the assumption OF the values obtained from
testing smaller columns. In the case of
stone. the small pieces tested were with
out the usual quarried defects and seams
which are to be found in larger pieces of
stone. ana such tests as have been made
show that the strength OF the stone de-
creases as the size Of the stone increases.
In tho erection OF large buildings the
strength Of these columns becomes a very
important matter and it is absolutely nee
essary that there be accurate data as to
the strength which may be expected from
these materials when used in larger masses.
Accurate Knowledge Wanting.
"In.the rapid development Of this coun-
try the seHormous locomotives of constantly
Increasing size and the heavier tonnage
have demanded constant increase in the
size OF bridges, with built-up structural
members of such size that we have been
unable to keep pace with experimental data
TO serve as q guide for such structures.
As a. result today we have practically no
knowledge of the strength OF these struc-
lures from actual tests and must base our
information on the tests of very much
smaller members. Bridges. such as that
which collapsed at Quebec. composed of a
number OF members held together by riv-
eted connections depend largely upon the
design and Workmanship, and this failure
has demonstrated it is absolutely necessary
that tests of largc,siEed members be made
in order that the engineer may know to
what extent the. buit-up structure is af-
fected by the workmanship, so that he may
know what strength to allow for these riv-
eted CONNECTIONS. There Is no machine in
the world at the present time that could
test a chord Of the size of that which failed
in the Quebec bridge, or OF the size OF the
recently completed Blackwell island bridge.
A Raebins of the capacity which we are
building in Pittsburg would test pieces OF
one-haif the full size OF these large chords
10 within the elastic limit OF the material
and would give the necessary. information
which is so desired by the engineer"