Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-10-04

Washington. The Investigators 60
~ ing to work now scientists. and
their problem Is to find out whether
skyscrapers-including the 10 and
20 story skyscrapers Of the average American
city-are safe.
One key question the probing scientists will
seek an answer for is: Just what is the effect
of terrific winds skyscrapers-winds that
often make the tallest buildings sway?
In charge of Uncle Sans investigation, the
only Government SkyScraper probe ever at
tempted is the United States Bureau Of Stand
ards at Washington. with capable staff OF
technical experts equipped with unique
instruments.
That every city in the Nation will be inter-
ested vitality in the probe is shown by the fol-
lowing Government statistics: There are about
478O buildings 10 stories or more In height
located in I31 of 173 cities with $4,000 or more
population OF these, about Is structures are
taller than 500 feet, while three or four others
more than 800 feet high have just been
completed.
NR. H. L. DRYDEN. expert on wind velocities
- for the Bureau of Standards, is the man
in charge of this program. The very f1rst step,
now under way is the making of a miniature
model Of the titanic Empire State building
The model will be tested under various condi-
tions of wind velocity.
e1he miniature building which will be about
feet high and made of aluminium plate, Dr.
Dryden says lis being made from complete
set of blueprints very kindly furnished us by
the architects office at the Empire State
building OF course, the model won't have the
exact surfaces and window arrangements OF the
actual building But the general story and
structural arrangements are being simulated as
closely possible"
DR. DRYDEN tells Just how Uncle Sam will go
about checking up his model tests with the
actual measurements being conducted on the
full size structure:
when our model Is completed" he says.
eve will place it in our 10-foot wind tunnel at
the Bureau of Standards and measure pressure
conditions and wind speed at the same places
on the models surface that are being measured
on the building itself-thrty-hfth, hfty-hfth
and seventy-fifth floor levels.
Experience in wind tests has taught US
that the corresponding pressures and speeds
ought to be substantially the same. If this is
So builders of great skyscrapers of the future
will not need to go to the expense, trouble and
labor of cutting wind and sway measuring in
struments in the buildings at strategic points.
For models will do the work quicker, cheaper
and more efficiently.
However" DR.. Dryden continues, lin this
connection it should be borne in mind that our
Government Is not testing the strength OF the
model under examination, but Is simply meas
uring the effect and force Of the wind on the
model We can simulate wind conditions in our
wind tunnel up to 10 miles an hour
1--WE shall fasten the model securely in the
wind tunnel and measure the pressure at
number of widely distributed pressure holss for
different wind speeds and wind directions. Or,
we shall attach the model to suitable balances
and measure the overturning moment and It's
point of application"
"A TrTHIN the real Empire State Building it
wv self instruments called extensometers
have been attached to the four corners of