The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1902-11-16
SAFETY OF BUILDINGS
METHODS or TESTING THE POWER
OF BUILDING MATERIALS.
instrument. Delicate Enough to Reg
lister the Pressure of N Finger
ON n Steel Plate.

be it's most important field of observation
and study, few persons realize how impos-
sible would be the erection of a modern
city. the establishment OF a modern rail-
road or the building of a modern steamer or
battIeship without a certain amount OF pre-
liminary work in scientific Laboratories. To
US as Americans what is perhaps even more
Interesting is that the important European
laboratories, now playing this absolutely
necessary part in twentieth century civili-
cation. are based upon methods that orig
mated on this side of the water. Such is
one of the conclusions of Prof. Z. W. Mil
Ter, of the Massachusetts, Institute of Tech
nology, who has just returned TO Boston
after a tour Of the best known technical
schools and government experiment sta
lions Of England and the continent. Never
an important building. or a big vessel. a
ship dock, railroad bridge or any one of the
Indefinite number Of large modern struc-
lures for the comfort and convenience of
humanity Is built until the material is thor
oughIy tested TO see il 1t will bear the
strain 10 which il must be subjected. Nat
urally the laboratories of the world are al
ways watching each other; the authorities
OF the great German institution at Chariot
tenburg. for example, keep a watchful eye
on the Massachusetts Institute OF Technol-
ogy and the Institute of Technology sends
its representative TO visit Charlottenburg
At first glance this seems simply an ex-
ample of the rivalry of important educa-
tionaI institutions. But in reality. having
in view the actual relations between the
modern laboratory and the building pro-
cesses Of modern civilization, 1t is also In
the long run, a rivalry between national
Qualifications In London where the buSi-
ness quarter is said to be threatened by
an invasion of the lofty American office
building, there is already tangible opposi-
ton on the ground that the buildings are
still an experiment and probably unsafe
10 tenants. The answer of course lies in
the continued safety of the high building
and this I'm turn depends obviously on the
accuracy with which the material has been
tested. Before the high building became
so important a part of modern construc-
ton these tests were made with small
pieces of the material from which the
strength of larger sections was deduced
by complicated a~rithmetical calculations.
But the erection of taller buildings, as well
as the growth OF ships, teamers bridges,
etc, found these tests unreliable and the
Massachusetts, Institute of Technology, not
so very many years ago, took the pioneer
step of adapting its Laboratories TO test
ing full sized material by the methods now
almost universally followed on both sides
of the water.
BEGINNINGS OF BUILDINGS.
To see these tests in progress is an in
teresting glance at what is practically the
birth of many a familiar structure, whether
the office building of a big city. the floating
fortresses of a navy or the railroad bridge
- I-1D T. = -,o,1ta;-.
hundreds of miles from civilization. In the
engineering laboratories of Tech. as the
prophet OF modern testing is best known
In its own immediate neighborhood of
Massachusetts,. these tests are In progress
not only night and day, but some of them
lasting over several years of constant
strain and pressure on a given piece of ma
terial. The laboratory itself is what seems
almost a chaos of powerful machinery
whose sole purpose is to bend, twist, pull or
push the various materials of modern con-
struction TO their last points of resistance.
Wooden beams, for example, are kept here
under constant pressure for years, their
sag being recorded from day to day to de-
termine just how much the timber is de-
iected during the life of a building in which
II Is placed-a long continued experiment
which, among other things. looks forward
to remedying the often uneven floors of a
cotton mill.
II a contractor is building a church a
masonry arch large enough for a church
door is tested with a weight comparable to
that Of a church steeple. not loaded, TO be
sure. with so many pounds OF material, but
being compressed to the crushing point by
steel beams drawn downward by relentless
mechanical power. Steel rods are subjected
TO torsional or twisting tests in order that
the necessary dimensions of shafts for en-
gines, steamships and for all sorts of shaft
ing for the transmission of power may be
definitely settled. Bricks are compressed
unit. they crumble into dust, but the re-
corded result of many tests determine the
ssfe height Of a chimney or an Office build
Ing of brick construction. Steel columns
sre placed under compression until they
buckle or break. and it Is then known for
a certainty how many pounds they will
support without disaster.
Particularly interesting are the tests of
rope. in which the great difficulty is to get
It to break in the middle rather than at
the knot or fastening. Wire rope can be
tested by molding type metal around
the ends, and thus furnishing a grip
for the jaws Of the machine. In the
case of manila rope. the sailors IA
vorite hitch. the bow line, is found
TO be the most unsatisfactory knot of
ali. while two half bitches develop the
largest efficiency. OF course the efficiency
OF q rope is no greater than that OF the
knot by means of which II is made fast,
but when IL is desired TO learn the break.
ing strength OF the straight rope. knots
are abandoned and a careful eye splice is
put in each end. Held by an eye splice
previously dampened, the rope may be
broken in the center simply by e~xerting
sufficient pull. but it has been found thar
an average rope, before breaking. will have
stretched 20 per cent. beyond its norma.
length.
THE DELICATE APPARATUS.
But not less interesting than the expert
ments Is the delicacy of the apparatus
that measures the results. Not long ago
a sheet OF steel-or steel plate. as it 1:
called before it IS worked into a steam
boiler. water tank. ships hull or what
not--was put into the huge machine
that tests steel to discover how mucf
resistance IL will offer TO a strain pulling
II 10 pieces. The plate was twenty inche: