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XI BRARY

OF THE
U N IVERSITY
Of ILLINOIS



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TH
v.47-49



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THE



ICHNOCRAPH



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WA



UNIVERSITY of ILLINOIS




OCTOBER 1Q32



MEMBER. OF ENGINEERING COLLEGE MAGAZINES ASSOCIATED



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Engineers —

The Technograph Is Your
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Support it by patronizing its
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5>






THE TECHNOGRAPH

I NIVERSITY OF ILLINOIS
Member of tin Engineering Collegt Magazines Associated

Randall A. Forsrerc '33 Editor

A, E. Wanderer '33 Business Manage)

Associate Prof. J. J. Poland Faculty Idvisoi

The various positions mi the editorial and business staffs will
In announced in the November issue

ASSISTANTS

A. Nauman, A. Kleszewski, ]. Pa-k I. Bradish, R. Stevens, VV. Barnes, J. Stewart, I. Roesel,
R. Maybury, T Fleming, R. Hoffman, S. Schnitzer, F.. Stater, ('. McBurney, II. Burns, R.
Caldwell, II. Caquelin, (,'. Hathaway, J. Nauman, C. Rover. ('. Slaymaker, II. Tracy, II. Wad-
dington.

Voli'me XLVII Urbana, Illinois, October. 1932 Ni mber 1



Contents for October

Engineering Features of a Century of Progress 3

Bert M. Thorud 'IS

( jeophysical Research on Geologic Structures in Illinois 3

Ro/icr/ P. Stevens '34

Subgrade Soil Studies Furnish Valuable Information to the Highway Engineer 7

Prof. Edivard E. Bauer '10

Editorials I' 1

Alumni Notes 12

Departmental Notes 14

15 ticket and Shovel 16



Members of the Engineering Magazines Associated
Chairman: Willard V. Merrihue, 1 River Road, Schenectady, X. V.



Armour Engineer

The Iowa Transit

[owa Engineer

Colorado Engineer

Nebraska Blue Print

Sibley Journal of Engineering



Rose Tecbnic
Michigan Technic

The Ohio State Engineer
The Pennsylvania Triangle
Purdue Engineer

Oregon State Technical Record



Minnesota Techno 1 og
Wisconsin Engineer
Tech Engineering News
Cornell Civil Engineer

Kansas State Engineer
The Technograph



Penn State Engineer
Kansas Engineer
Marquette Engineer
Auburn Engineer
Tennessee Engineer



Published monthly by the Illini Publishing Company. Entered as second class matter, October 30, 1921, at the post office of
Urbana Illinois.' Office 21.' Engineering Hall, Urbana, Illinois. Subscriptions J1.00 pet year. Single copy, -'" cents.




This beautiful view of the Boneyard is familiar to all lllini engineers



i oui tesy The Illio



The Teonogp^pH;

Published Monthly by the Students of the College of Engineering — University <>j Illinois



Volume XI.VII



I'rbaxa, Illinois, October, 1932



Ni mber 1



Engineering Features of A Century of Progress



By Brrt M. Thori'p '18



CHICAGO'S 1933 World's Fair— A Century of
Progress Exposition — is giving the architects and
builders of this era an opportunity to test out and
develop modern ideas, just as its predecessor of 1893 per-
mitted the architects of that time to express themselves
in the classical style.

The architecture of this Exposition has aroused con-
siderable comment. It is new and different from any-
thing of the past. Yet it is being developed from very
practical ideas, resulting from utilization of successful
experimentations. The in-
novations may lead to
new applications having
important consequences to
future building construc-
tion.

Since the life of the
Exposition will be L50
days, or from June 1,
1933 to November 1,
1933, the architects are
building structures for a
temporary purpose and
not for permanence. The
factor of economy is
vital, yet the buildings
must conform to the best
engineering and struc-
tural practices. Materials
that are economical in
original cost, that will
have some salvage value
when the Fair is over and
that will permit of dis-
sembly at low cost are being selected,
parts are being made use of to a
materials are prefabricated in




This



Factory-made
large extent. Wall
shops, cut into standard
shapes and sizes and shipped to the Fair grounds. They
are applied to steel frames with clips or screws. The
amount of time and labor and materials saved in these
(ield operations is a considerable factor of economy. The
materials are of light weight. They are easy to handle
and require less steel. In most cases the steel is bolted
together, instead of being riveted.

The typical framework of the various buildings al-
ready constructed, or to be built on the Fair grounds,
has developed into a system of girders and columns ex-
tending across the width of the buildings at 20 foot in-
tervals with steel joists extending length-wise of the



building, framed to the girders. Twenty feet has been
seelcted as the most desirable division of space for ex-
hibition booths and is also the economical span for steel
truss joists for the support of floor, terrace and roof
decks. This system also satisfies the general bracing of
the building as typical girder web connections together
with suitable seat angle connections to the columns, form
bracing bents for the typical story units. High stories
or halls have suitable riveted wind bracket connections.
Bracing beams replace the steel joists on column lines

parallel. Although a sat-
isfactory system has been
developed for utilizing
single piles under exterior
wall columns and a mini-
mum of two piles under
the interior columns, the
light dead loads of the
structure permit relative-
ly long span of girders to
stress the piling and the
minimum column sections
to their full safe load
capacity. This increases
tonnage of steel econom-
ically as the girder span
increases, by reduction of
the cost of piling per foot
of span.

Large halls are eco-
nomically framed with
trusses or deep rolled
sections. Towers, pylons,
projecting bays, fins, and
occur on all buildings are
or light struts, girts, and
diagonal bracing. Open spaces between web members
of the joists, between floor decks and ceilings, are utilized
as ducts of an exhaust ventilating system, the buildings
being generally windowless, thus saving expensive duct
installations.

On the steel frames of the various buildings, a variety
of different materials are being used for wall covering.
Since the Exposition, to a large extent, is a great labora-
tory where new materials are tested, new uses for old
materials tried and new methods of construction given
a practical tryout, some interesting utilizations have been
developed. For example, the outside walls of the Ad-
ministration Building are of asbestos cement board,



«/ the Hall of Science



canopies, which generally
usually framed of columns



THE TECHNOGRAPH



October, 1932





This view shows the Railroad Dome (left) and the Steamship Hall (right)



hitherto used principally in small units for insulation pur-
poses. Between the outside wall and the inside wall,
which is of gypsum wall board, an insulating material
made of waste paper and emulsified asphalt is used. The
resultant construction provides the equivalent of a
seventeen-inch wall in insulating value. On the Travel
and Transport Building, the walls are made of strips of
sheet metal clipped or welded to the steel frame. Gypsum
board covered with a coat of metallic paint forms the
exterior walls of the Electrical Group, comprising the
Radio, Communications and Electrical Buildings on
Northerly Island. This material is likewise used on the
walls of the Agricultural Building, and on the walls of
the first three pavilions of the General Exhibits Group
and it will be used on the Federal Building and the Hall
hi the States. On the Hall of Science, the exterior walls
are of plywood — a Douglas fir veneer of five thicknesses.

( )ne of the unique construction features is the ab-
sence of windows on most of the purely exhibition build-
ings. This innovation, like others in the Exposition
buildings, was made not for the sake of novelty or
"stunt" but with a highly practical intent. Everyone
familiar with exhibition buildings knows that sunlight
tin- day-time illumination is a variable quantity. By
eliminating windows, artificial light must be used and
the architect and exhibitor thus have constant control
over the volume and intensity of light, regardless of the
kind or time of day. The elimination of windows makes
possible important savings in construction cost.

Seventeen of the Exposition buildings are either stand-
ing or in the course of construction. These include: the
Administration Building; the Travel and Transport
Building; the Hall of Science; the Electrical Group,
comprising the Radio, Communications and Electrical
Buildings; the first three pavilions of the General Ex-
hibits Group; the Agricultural Building; the Dairy
Building; the General Motors Building; the Golden
Pavilion of Jehol, a replica of China's finest Lama
temple ; the replica of old Fort Dearborn ; the Lincoln
Group; the Federal Building and the Hall of the States.

< )ther buildings are on the schedule for construction,
including the Chrysler Building; the Sears, Roebuck &
Companj Building; the Firestone Tire and Rubber Com-
pany Building; the Thomas A. Edison Memorial; the
Johns-Manville Building; the Southern Cypress Manu-
facturers' Association Building; the American Radiator
Companj Building; Christian Science Publishing Society
Building; the Home and Industrial Arts Building; eight



exhibit houses in the Home and Industrial Arts Group;
Illinois Host Building.

A description of some of the buildings now standing
or under construction and some of their unique archi-
tectural features may be of interest.

The Administration Building, with halls of lofty
ceilings, warm colors and advanced form of illumination
was the first Exposition Building to be designed and com-
pleted. In the form of a huge letter "E" with the three
wings of the open side facing a lagoon and the closed
side paralleling Leif Eriksen drive, one of Chicago's
water front boulevards, this building combines the prac-
tical with the decorative in architecture. The building
is 350 feet by 150 feet, of modern design and located on
sloping filled-in land. On the lagoon side the three
wings are stepped down in terraces to the water's edge.

( )ne of the most remarkable of the new architectural
concepts is found in the Travel and Transport Building.
A unique departure in construction practice is evident
in the structure of the dome. With a clear interior
diameter of 206 feet and approximately the height of a
twelve story building, the dome itself is entirely clear of
pillars or other interior supports. Instead of being sup-
ported from below, the roof is suspended by cables at-
tached to twelve huge steel towers ranged in a circle.
The absence of interior supports provides some obvious
advantages for an exhibit hall. The main Travel and
Transport Building is 1,000 feet long, and two stories
in height.

The Hall of Science promises to be one of the most
talked-of buildings of the Fair. This is a great I -shaped
building planted over Leif Eriksen Drive, with two long
wings reaching down to the lagoon. The Hall of Science
is a two-story structure, 700 by 400 feet, with a mez-
zanine. A great ramp leads up to the north facade,
around which tall pylons rise in a semi-circle. Within
the LT space, which is like a quadrangle with an open
end, a beautifully designed rostrum is provided which
will be covered with bas relief ornaments. Here speakers
may address thousands of people in the court. A tower
approximately 176 feet high rises in the southwest corner
of the court, fitted with a carillon which will record the
time of day with its chimes and play a wide variety of
tunes on its tubular bells. Dramatic illumination effects
are used at night.

Opposite the Hall of Science on Northerly Island
rises the Electrical group. This group 1,21)0 feet long

(Continued mi Page 11)



Geophysical Research on Geologic Structures
in the State of Illinois



By Robert P. Stevens '34



THh engineer of today is beginning to realize the
value of applying geology and its principles to his
particular branch of the engineering profession. For
a long time, a sort of hit-and-miss form of prospecting
was used in locating such things as minerals and water
supplies. In later years diamond drilling has largely
replaced the old way and gives one a very definite idea of
the existing conditions. It has one drawback, however,
and that is one of cost. The geologist then turned to a
branch of engineering for low-cost assistance, namely
physics.

About ten years ago, two men, O. H. Ciish and W. J.
Rooney, developed a method of measuring the resistance
of the earth when a known amount of current is intro-
duced into the circuit. In 1916, F. Wenner, of the
United States Bureau of Standards, advanced the theory
that in a homogeneous mass of a plane surface and of in-
finite extent, the specific resistivity of the mass can be
determined by placing four electrodes in one straight line
and having an equal spacing between them. By consid-
ering the earth as a sphere, the stratum become thin shells
composing this sphere. With the use of Ohm's Law and
using an element of the shell, the specific resistance of the
element was determined. The difference in potential in
moving this element from V„ to l\ is expressed by the
equation :

p/



r,,-/',



.(l/r -l/r n )



where "p" is the specific resistivity of the median used
(earth) and "r" is distance from the center of the
sphere.

The knowledge of equi-potential fields existing be-
tween a positive and negative terminal, -(-/'. and — V

respectively, reveal the fact that /', (the potential at P
due to -{-/' ) equals

and V„ (the potential at P due to — /' ) equals



9l



t/r B — 1



r..



Let ill = a and r,
equations we have:



n ; >'.,=



P,-P.,=



-?/



Combining the abo\



dV



With a change in sign and transposing terms we have the
equation stated in terms of the specific resistivity:

dV
p = —j—2-(i,

"a" being the unit of equal spacing.

This method of geophysical prospecting seemed
adapted to the economic geological problems that the Illi-
nois State Geological Survey were studying, and conse-
quently during the past summer they sent a party to
Hardin County in the southeastern part of the state to
study the structures found there. In this part of the



state, the vast prairies disappear and their place is taken
by very rough topography, the hills being a part of the
Ozark formation from neighboring Missouri. They are
one of the oldest structures exposed, being thrown up by-
earth movements before the ancient Appalachian Moun-
tains were formed. If the movement of the earth's crust
is sudden, the surface will not bend into hills and valleys,
but will break with the stress and slip. Such an action
is called a fault. In this particular portion of the state
the fault cracks, along which displacement took place,




Fig. 1. Instrument box showing recording of data



have later been filled by calcium fluoride solutions, and
the result is the formation of vein deposits of fluorspar.
This mineral, having a density of 3.16, is roughly 49 per
cent calcium and 51 per cent fluoride. Its chief use is as
a flux in the steel industry, but it is used also in making
hydrofluoric acid and enamels. The spar frequently
crystallizes in cubes having a perfect octahedral cleavage,
and when clear is used for refractory lenses. An area of
40 square miles in the vicinity of Rosiclare, Illinois, pro-
duces about 0(1 per cent of this country's supply of fluor-
spar. Any attempt to locate underground deposits of this
material by ordinary density methods is impractical since
the density of the mineral is practically the same as the
surrounding rock-limestone and sandstone. But by locating
these faulted zones where the minerals usually occur, we



the tfciinocjrani



October, 1932




fir/. 3. (ir/iph of profile across f milts in hmestont and sandstone showing related cross-section



can usually safely assume the presence of the mineral.
Thus we were primarily interested in detecting the fault
zones found in this region. M. King Hubbert, Columbia
University, headed the party of three as Geophysicist and
his assistants were B. H. Richards, University of Wis-
consin, and the writer.




Fig. 2. Srt-up showing hand cranked commutator
147/// wires in foreground

The instrument (Fig. 1) consisted of dry batteries
having a potential of approximately 90 volts, a voltmeter,
an ammeter, a hand cranked commutator, and a hydro-
gen-ion potentiometer. Four iron stakes were used for
terminals into the ground. Although they were copper-
covered to increase the conductivity, considerable diffi-
culty was experienced with their use on the two potential
terminals. In dry weather, the absence of moisture in



the sod hot the internal resistance of the hook-up con-
siderably higher than it shoidd have been for best re-
sults. Whenever cinders were encountered, the iron
stakes formed a nice battery and the back F. M. F. made
erroneous results. When all-copper stakes were used on
the potential terminals these difficulties were lessened, al-
though not entirely eliminated. Two reels of insulated
copper wire cut to desired and uniform lengths were used
as current lines. By using ordinal) - single-pole connec-
tions and plugs, the set up (Fig. 2) was accomplished
fairly easily.

In working traverses across the faults a constant in-
terval between stakes was used, being 100 feet. The in-
strument was placed in the center, being 150 feet from
the outside current stakes and 50 feet from the inside
potential ones. With the interval constant, the ratio of
the potential picked up to the current sent out gave the
specific resistivity of the medium between. By plotting
these successive values for "p" we obtained an irregular
curve. When a major fault was passed, the outcropping
rock would change. As the resistance of limestone is
much higher than that of sandstone (limestone and sand-
stone were the predominate rock present in this vicinity),
the resultant curve would vary proportionately. Hence,
the graph curves (Fig. 3) gave us a fault index. The
main traverses were several miles in length and followed
main roads. Parallel traverses were run where details
were needed. By connecting the fault peaks shown on
the graphs when properly correlated as to position, the
strike of the fault can be determined approximately.
Where there were exposures of the strata, it was a fairlj
easy matter to check the profiles with the actual fault
zones. It will be necessary to make a detailed study of
the geology of this section where the traverses were run
to produce an absolute check on the new faults that the
field party located.

Although none of the three large shaft mines in the
vicinity are working, due to large surplus of stock and
present conditions in the steel industry — the outlet of S3
per cent of the total fluorspar mined, a few smaller slope
mines in the bedded deposits east of Rosiclare are still
digging the spar. Flic Rosiclare shaft is down to 7_'0
feet anil has had quite a bit of difficult) with water
which seeps in from the adjacent Ohio River. In con-
junction with the Fairview shaft on the same vein hut
nearer the river, the two mines must pump in excess of
3,500 gallons per minute each to keep even with incom-
ing water. During the present shutdown the mines are
(Continued nn Page 11)



Subgrade Soil Studies Furnish Valuable Information

to the Highway Engineer



By Edward E. Bai er '19
Assistant Professor of Civil Engineering



Prof. Bauer has done considerable research along the lines uf
highway materials and is the author of several books dealing

•with the same. The following article tells something of his
wnrk with soils in connection with their use in road work. Cuts
were furnished by Michigan State Highway Dept. — Editor's Note

NOT long ago a 40-foot section on Ohio Route 17
about one mile east of the Goodyear-Zeppelin
Corporation hangar at Akron, Ohio, suddenly dis-
appeared, leaving a pond of water where the road had
originally been. The road was built across a peat marsh
which was practicallj a liquid mass 40 to 45 feet deep.
Highway surfaces depend for their support upon the




A_-GLA» TU



the PuenOMtnon op- CADiLLAaiTY
PuncTion of- .soil— tectuee. mot af-f-

BY AttTI F1CIAI OH.AIMA6e

F-IS.-1



Subgrade soil studies maj be divided into two general
parts: (1) laboratory studies of the physical properties
of the soils themselves to determine subgrade soil con-
stants and to learn certain characteristics behaviors, and
(2) investigations of the behavior of these soils in the
field. The two groups of studies are naturally closely
interrelated.

Soil Constituents. Soil constituents are generally

classified according to the size of the particles, as follows:

Gravel, larger than 2.0 mm.; Coarse Sum/. 0.25 mm.

to 2.0 mm.; Fine Sand, 0.05 mm. to 0.25 mm.; Silt,

0.005 mm. to 0.05 mm.; Cohesive Clay, smaller than

0.005 mm.; Gluey Colloids, smaller than

0.002 mm.

It should be noted that the soil
physicist uses a different size classification
for gravel and sand than is in common
use by engineers. Colloids are also often
rated as particles smaller than 0.001 mm.
( I micron).

Determinaton of Subgrade
Soil Constants

There are six routine tests to be made
on subgrade soils from the results of
which the performance of the soil as a
subgrade material may be fairly accurate-
ly predicted by an experienced subgrade
soils engineer. The procedures given
are those of the United States Bureau of
Public Roads. All results are based on
weights of soil dried at 110°C

Preparation of Soil for Testing. The
soil as received is air-dried and broken
up in a mortal' with a pestle. An effort



-m v&.r-,-r^>



:CTfcO



underlying earth. If that support is not
uniform or is weak, it may fail to fulfill
its purpose. When improved surfaces are
built upon soils subject to extreme
changes in volume at certain seasons, uni-
form support is lacking and destructive
counter forces may result in serious
heaves, frost boils or excessive pavement
cracking. No surface is able to resist
successfully these forces of nature.

In order to design properly the pave-
ment surface, the highway engineer
should be able to recognize readily the
different types of soils and to know their
characteristics as they affect his prob-
lems. In many of the state highway or-
ganizations specially trained soils experts
are employed to make surveys and recom-
mendations, since practically none of the
highway engineers of today have had any
training in soils work.




r-lf



ii

it



j4v f



CAPil.1



COLUMr



buPPO^T &0 e>-r



8



THE TECHNOGRAPH



October, 1932



is made not to break anj oi the particles but merely to
separate the soil into its component parts. 1 he sample
for the hydrometer test must pass a 10-mesh sieve (open-
ing between wires is 2.0 mm. or 0.0787 in.), while the
samples for the other tests must pass a 40-mesh sieve
(opening 0.42 mm. or 0.0165 in.)

Particle Size. Determination of the size of particles
requires the use of sieves and a special hydrometer. A
sample passing the 10-mesh sieve is mixed with water using
a special milk-shake machine, after which an hydrom-
eter developed by Professor G. J- Bouyoucos of Mich-
gan State College, is immersed in the mixture and read-
ings taken at intervals of 1, 2, 5, 1 5, 30, 0(1, 250, and 1440
minutes. As the particles settle the specific gravity of the
solution changes. The maximum grain size at the time
of any hydrometer reading is computed by means of
Stokes' law. Particle sizes smaller than 0.074 mm. (200-
mesh sieve) are de-
termined by the hyrom-
eter and those larger by
sieves.

Plastic Limit. The
plastic limit is the
lowest moisture content



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