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"wet" or "very wet", contains a great deal more water than was used
in any of the mixtures from which the specimens were made. Even
in the very wet mixtures, the notes in Table S-A indicate that the
concrete was tamped. In ordinary practice, very wet or even wet
concrete would flow into place, and it would be so soft that tamping
would not be necessary, nor could it be compacted in this manner.
The writers believe, as a result of their investigation previously referred
to, that, with concrete subjected to sea-water action, the best results
are invariably obtained when a consistency is used which will permit
of light tamping. This light tamping should produce quaking in the
mass. If the concrete is mixed too dry, a porous condition will result;
and if too much water is used in mixing, a lack of density, together
with a chalky condition of the surface, results. In both cases, the
concrete is very susceptible to disintegration by sea-water action. For
reinforced work, as usually constructed, a slightly wetter mixture is
required than what the writers believe to be the best consistency, owing
to the necessity of thoroughly embedding the reinforcement.

It is possible, however, that some method may be devised of placing
the concrete for reinforced work so that the ideal consistency can be
used and, at the same time, secure thorough protection of the embedded
steel. The ideal consistency is that which produces concrete of
maximum density.

The author indicates that great care was exercised in proportioning
the aggregates and in mixing the concrete, the time of mixing, after
all the ingredients were placed in the drum, being about 2 min. This
undoubtedly had a very beneficial effect on the concrete.

In many of the structures examined by the writers the deterioration
in evidence, at least in part, can be attributed to a lack of care in
preparing the concrete. More care must be taken in the mixing of
the concrete than has too often been the case in the past, if more
successful results are to be secured with concrete structures in sea
water. In fact, far more care must be taken in every operation con-
nected with constructing concrete which will be subjected to sea-water
action than is necessary for land structures.


Only by giving strict attention to minute details, which in land Messrs.
structures would be trivial, can satisfactory results be obtained. Minor ^'f
defects, which ordinarily would be unimportant, are often the starting Ferguson,
points of deterioration which ultimately spreads to sound parts of
the structures and cause failure when sea-water action is to be resisted.

Although the information which Mr. Bakenhus presents is of
great value for the locality of Boston, care must be taken in drawing
too general conclusions from it. There is a great difference in the
action of sea water on concrete in different localities due to climatic
conditions as well as varying physical actions, such as wave action and
abrasion from floating debris and ice.

The saline content of the water also has a marked effect. The
undiluted sea water along our coasts does not vary greatly in the
quantity of salt contained, but, where structures are near the mouths
of rivers, the sea water is frequently diluted to a considerable extent.

The writers believe that few very general statements can be made
on the subject of the effect of sea-water action on concrete, but the
peculiarities of each individual locality must be studied before
attempting to state the methods to be followed, which will insure
permanent concrete structures.

R. E. Bakenhus,* M. Am. See. C. E. (by letter). — The writer has Mr.
read with interest the various discussions of his paper. Information
is offered tending to confirm the results of the Boston tests. The
opinion advanced by Mr. Yates that, in setting, a surface is formed
on concrete, which will resist successfully the action of sea water on
cement, is significant. If a surface coat protects the concrete from
the chemical action by sea water, then it becomes very important to
know the character of this protective surface, to encourage or bring
about its formation, and to protect it from mechanical injury. Mr.
Yates cites examples of bridge piers in fresh water showing no deteri-
oration from freezing and thawing and no chemical action, though
mechanical injury to the surface exists. This tends to bear out the
theory that it is the chemical reaction between the sea water and the
concrete that is responsible for most of the deterioration of the latter.

A number of causes are undoubtedly contributory to the deteriora-
tion of concrete in tidal sea water. It depends first on the destructive
agents existing in the sea water and the atmosphere, and second on the
materials of which the concrete is made and the manner in which they
are combined. The active possible destructive forces may be listed as
follows :

(a). — Mechanical injury by floating objects or debris;
(h). — Mechanical injury by water, waves, and currents;
(c). — Mechanical injury by wind action;
* Washington, D. C.


Mr. (d). — Mechanical injury from freezing and thawing;


(e). — Chemical reactions between the sea water and cement;

(/). — Chemical reactions between the sea water and the sand or
stone of the concrete;

(g). — Physico-chemical reactions of the sea water and the con-
crete, such as the solution of elements of the concrete in
sea water, or the formation and deposit, in the pores of
the concrete, of crystals occupying greater volume than
the original materials, accompanied by minute internal
stresses ;

(h). — A combination of any or all of these destructive effects.

The elements tending to resist destruction may be listed as fol-

(a). — Density of the concrete, that is, reduction of pores to a

minimum, accompanied by increased resistance to internal

stresses ;
(&). — Thorough mixture of the ingredients, so as to give a uni-
form composition of the mass ;
(c). — Freedom from accidental defects, which may act as starting

points of deterioration;
(d). — Chemical and physical characteristics of the cement, sand,

and stone, making these materials neutral in the tidal

range of sea water;
(e). — Strengthening of the concrete by a high proportion of

cement ;
(/), — Formation of a protective coat, which is inert in the tidal

range of sea water and which, unless mechanically broken,

prevents chemical action.

Deterioration is the result of the interaction of the various destruc-
tive forces and the resisting elements. In the tests which have been
described, the effort was made, by comparing parallel series of speci-
mens, to single out and test the variable elements in the concrete
itself, one at a time. The destructive elements of the sea and air
might have been similarly segregated, and, in addition, the tests might
have been repeated in various climates and in fresh water, as well as
in salt water, so that the effect of mechanical injury from floating
debris, the effect of wave action, the effect of freezing, the effect of
climate and of moisture and air, and, finally, the effect of the chemical
and physico-chemical action of the sea water might have been inde-
pendently determined. In part, this is accomplished by the specimens
extending below low tide and above high tide. In the absence of any
more elaborate series of tests, the experiences with actual structures
in many localities may supplement the data already available, and


enable engineers to reach definite conclusions. The writer, therefore, Mr.
looks forward with interest to the report of the extensive investiga-
tions made by Messrs. R. J. Wig and Lewis R. Ferguson, for the
Bureau of Standards, in all parts of the country.

In tidal sea water at Boston, the destructive effects, as shown by
the tests, occur where the concrete is alternately exposed to the sea
water and the air. Exposure to either the sea water or the air alone
did not bring about deterioration. This would indicate that it is not
simple chemical reactions between sea water and cement that bring
about destruction of the concrete, as these could go on below tide level
as well, but that the reactions are dependent on air as well as on
water, and are most probably of a physico-chemical nature.

The effect of integral water-proofing on the durability of concrete
in sea water is discussed by Messrs. Larsen and Rhett. The very
interesting tests for the Grand Trunk Railway, at Portland, Me.,
referred to by Mr. Larsen, agree with the Boston tests in. showing
that concrete can be made without so-called integral water-proofing
and remain in sea water for several years in perfect condition.

Two of Mr. Larsen's specimens, treated vdth external water-
proofing, did not fare so well as the plain concrete; and six, made
with cement, combined with various water-proofing compounds, are
stated by him to show very marked deterioration.

Three of the Boston specimens were mixed with materials of the
so-called integral water-proofing type. No. 22 had a mixture of 1
part of hydrated lime and 9 parts of cement. No. 23 was mixed with
Sylvester wash, made as follows :

(a). — Bar ^ap, light colored, dissolved in water, 1:^ lb. of soap

to 15 gal. of water;
(&). — Powdered alum, 3 lb., mixed with each bag of cement;
(c). — Materials of concrete mixed dry;
(d). — Hot soap solution dumi^ed into a barrel of cold water, and

used to mix the material to the proper consistency.

No. 24 contained pulverized clay in the proportions of 1 part of
cement, -jo P^rt of pulverized clay, 3 parts of sand, and 6 parts of stone.

The clay specimen fared very well, but this is not true of the
specimens containing hydrated lime and Sylvester wash.

The Boston tests are not sufficiently extensive as to the use of
integral water-proofing to warrant drawing any general conclusions,
and it cannot be stated, as a general principle, that they, in them-
selves, showed that integral water-proofing has a detrimental effect
on concrete. Mr. Larsen's tests were more complete on this point,
and show consistent results. The Boston tests do not include the


Mr. use of external water-proofing, such as was used in two of Mr. Larsen's

Bakenhus. , ,


Although most of the data available from these two series of tests
are not favorable to the use of integral water-proofing, it may be
possible, nevertheless, to discover a compound which would improve
the durability of concrete in sea water. Very complete tests vuider
service conditions will be necessary to determine finally whether a
helpful integral water-proofing can be found.

It is shown by the tests that certain concretes are not stable in
sea water at tide levels. Other concretes are stable in the presence of
the forces, chemical and physical, that are active in sea water at tide
levels. The dividing line between the two classes is not sharply
marked. Knowledge of the action and effect of these forces is just as
important to the engineer in designing successful concrete structures
in sea water, as knowledge of earth pressure, hydrostatic pressure, or
other loads. A very considerable volume of empirical knowledge is
now available for the engineer from these tests and from other sources.
■Under existing conditions, it is apparent that concrete structures in
sea water should be planned with care, and only by those who have
special knowledge of the subject.




This Society is not responsible for any statement made or opinion expressed
in its publications.

Paper No. 1394


By F. C. Carstarphen, Assoc. M. Am. Soc. C. E.f

With Discussion by Messrs. Richard Lamb, H. F. Scholtz, and
F. C. Carstarphen.


This paper gives a brief statement of the prominent features of
the location, construction, and operation of an aerial tramway built to
carry salt, at the rate of 20 tons per hour, a distance of 13^ miles,
from Saline Yalley, over the Inyo Mountains, to a point in Owens
Valley, California.

It is assumed that the reader is familiar with the terminology
of aerial tramway design; also, that the ability of an aerial tramway
system to transport materials economically and efficiently at the
rate of 250 tons per hour or less is so well known as to make extensive
discussion of these points unnecessary.

California now possesses one of the most novel aerial tramways
ever constructed. This was built over the Inyo Mountains for the
Saline Valley Salt Company, of Los Angeles, Cal.

In 1904 Adolf Bleichert and Company completed for the Argentine
Republic, a tramway, 22 miles in length, with a difference in terminal

* Presented at the meeting of May 2d, 1917.
t Now M. Am. Soc. C. E.


elevations of 11 500 ft., thereby establishing a record for length of
lines operated continuously and successfully. In 1915 the American
Steel and Wire Company completed an aerial tramway for the Spring
Canyon Coal Company, of Storrs, Utah, which carries 285 tons of coal
per hour.

Although these two structures exceed the Saline Valley tramway
in length and capacity, respectively, neither of them crosses a moun-
tain range, nor does either show such boldness of engineering design.
The engineers who undertook the construction of this tramway were
fitted by experience to solve the many problems which confronted them.
As early as 1895 the Trenton Iron Company designed a tramway, 12
miles long, for the Compagnie Haitienne, of Port de Paix, Haiti, and
it has been maintained in successful operation ever since.

The purpose of the Saline Valley Salt Company, in building this
aerial tramway, was to transport salt from Saline Valley, over the
Inyo Mountains, to the railroad in Owens Valley. The tramway is
in Inyo County which is remarkable as possessing the highest and
lowest spots in the United States. Mt. Whitney, elevation 14 501 ft.,
is the crowning height of the Sierra Nevada Mountains, forming the
west wall of Owens Valley; Death Valley, to the east, has an elevation
of minus 280 ft., and is the lowest spot in the desert. An observer
standing on the summit of Telescope Peak of the Panamint Range
can view the extremes in elevation of the Republic.

It may be remarked in passing that Owens Valley, elevation approxi-
mately 3 600 ft., possesses a river of such magnitude that the City of
Los Angeles has built an aqueduct, 274 miles long, for the purpose
of making this mountain stream available for the domestic water
supply of the city. The Owens River flows into Owens Lake, which
is a dead sea, without outlet. The waters of this lake are sufficiently
rich in sodium carbonate to make its extraction profitable. At present,
plants on the east side of the lake are producing soda ash and sodium
bicarbonate in large quantities.

To the east, beyond the Inyo Mountains, is Saline Valley, with an
elevation of 1 100 ft. This valley has no water system, but is remarkable
for several large springs, and there is flowing water in Hunter Canyon.
To the east of Saline Valley lies the romantic Death Valley, its
depressed floor dotted with borax deposits. Thus, it may be noted, the
commercial worth of these valleys varies with altitude. The tempera-


ture of the summer air of Owens Valley is not excessive, but Saline
and Death Valleys are no doubt quite the hottest places that can be
found on earth. Temperatures of 120° Fahr. in the shade prevail
for considerable periods, and only because of the absence of humidity
can the summer heat be endured.

The topography of Inyo County owes its extreme boldness to the
simple nature of the faulting, which is responsible for the Sierra
Nevada and Inyo Mountains. When the great blocks of the earth's
crust were thrust upward they assumed a tilt toward the west, so that
the slopes on that side are gradual ; the east fault plane has been carved
into bold escarpments of exceeding grandeur. The elevations of the
floors of the valleys between the successive mountain ranges indicate
the relative power of the faulting forces. At the time of this great
displacement of the earth's crust, titanic agencies were at work, and
in regions of ancient volcanic activity deposits of precious ores are
often found. This district is not an exception. In the early Eighties
a gold stampede took place into the Saline Valley and the Ubehebe
Mountains forming its eastern boundary. It is said that more than
2 000 people were camped in this valley during the height of the excite-
ment. At that time it became generally known that there was a great
salt deposit of remarkable purity in Saline Valley. A view of this
deposit from the flanking mountains on the west is most impressive.
The most important portion of the salt flat covers an area of approxi-
mately 1 500 acres, and the purity of the salt is enhanced by a natural
refining process which is in constant operation, due to the remarkable
fact that there is a series of large springs on the western rim of the
salt flat, the water of which inundates the salt beds during the winter,
and yields to the excessive evaporation induced by the summer heat.
The retreat of the water deposits the pure salt crystals, which form
when the brine reaches the point of saturation.

The salt claims located at that time have always been assumed to
possess great value, provided transportation facilities could be obtained
to ship the salt to the various markets.

Surveys had demonstrated the impracticability of building a rail-
road into the valley; the mountain barrier was so great that the cost
of constructing such a line was excessive. Two methods of transpor-
tation were then considered. The first was by a pipe line over the
Inyo Eange, through which the brine formed on the salt flat could be


pumped to evaporating vats adjoining the railroad at Owens Valley.
This project was examined very carefully, and estimates of cost were
prepared, but it was found that although it was feasible for the trans-
portation of brine, it did not afford a means of bringing in the supplies
needed by the operations incidental to pumping. Accordingly, the
merits of an aerial tramway were discussed, and, in order to ascertain
the cost, and determine a suitable location for such a tramway, a
survey was begun in April, 1911, under the direction of W. H. Leffing-
well, M. Am. Soc. C. E. Several trial lines were run, and a location
was selected in the latter part of May. Under the direction of Mr.
C. H. Wickham, Field Engineer for the Trenton Iron Company, a
final location was completed in July. The profile, together with the
topographical surveys, were submitted to the Trenton Iron Company
for consideration. An estimate was prepared, and the final contract
was signed on August 14th, 1911, between The Trenton Iron Company,
a subsidiary of the American Steel and Wire Company, and the
Saline Valley Salt Company, a corporation of the State of Arizona.

This contract called for the preparation of the designs and finished
drawings, as well as the wire cables, carriers, and machinery, for a
Trenton-Bleichert tramway to carry salt weighing 60 lb. per cu. ft.,
the slope length of the line being 69 645 ft., the capacity 20 tons per
hour, the elevation of the discharge terminal above the loading ter-
minal, 2 450 ft., the carriers to have a volume of 12 cu. ft., and the
speed of the traction rope to be 500 ft. per min. This resulted in a
spacing of 525 ft., or 63 seconds, between contiguous carriers. More
than 112 h. p. were required for its operation. The following items
occur as prominent parts of the specifications:

Patent locked coil steel track cable, l^-in 13 850 ft.

" « " " " " ll-in 55 450 "

« " " " " " l-in 69 300 "

Special steel traction rope, |-in 141 000 "

Special steel buckets, capacity 12 cu. ft., with
protecting covers ; and hangers, carriages, and

patent compression grips 286

Intermediate supports 120

Track cable saddles 240

Steel traction rope rollers, with shafts, bearings,
bolts, washers, foot castings, etc 240


The specifications also included the supervision of the erection of
the timber work and attaching the machinery; the equipment for one
loading terminal, one discharge terminal, five intermediate control sta-
tions, twenty-one rail structures, twelve anchorage-tension structures,
and one double-tension structure; tools for coupling and splicing track
cables and traction rope; the necessary signal gongs for the control of
the line when in operation; track cable oiling cars, traction rope oiling
tanks, and water carriers.

The difficulties of construction on this line may be inferred from
an inspection of the profile. Fig. 1. Aerial tramways have been built
in the past so that the line traversed country possessing exceedingly
rough topography, but each has been distinguished by the fact that it
has been on the flank of a mountain range, instead of crossing it. It
was desirable to find the shortest route between the salt fields and the
railroad. The west side of the Inyo Mountains, though broken into
a number of precipitous ridges, does not impose extreme difficulties
to aerial tramway erection. The average elevation of the crest of
these mountains is 10 000 ft. above sea level, and it runs in a northerly
and southerly direction. However, there is a saddle in the crest line
with an elevation of 8 500 ft., so that it was desirable to have the tram-
way pass through this gap. By utilizing the difference in elevation
between the terminal stations, it was found that the 7 500 ft. required
to pass the summit could be obtained by dividing the difference in
altitude between the floor of Saline Valley and the summit into three
2 500-ft. sections; also, that the descent from the summit to Owens
Lake could be made in two 2 500-ft. sections. The selection of a con-
stant difference in the height of the several control stations was an
important factor in deciding on a constant size of traction rope for all
the sections. The use of intermediate control and driving stations
added flexibility to the location of the line, as any reasonable horizontal
angle can be made at such points.

The final location of the line is shown on the map. Fig. 2. It
starts from the edge of the salt field, at an elevation of 1 060 ft. and
runs south along the mesa for 2| miles to the foot of the eastern face
of the mountains, which has an elevation of about 1 800 ft. The line
ascends abruptly to Station 177 + 50, which has an elevation of 3 720
ft., where Control Station No. 1 is placed. The portion of the line
from the loading terminal to Control Station Wo. 1 is designated



g|«— IOOQPtr->|




117° 15' R.39 E.

117 15' R.3'J E.

10 Miles

Contour Interval 5U0 feet

Fig. 2. — Location of Aerial Tramway of Saline Valley Salt Company
(U. S. G. S. Topography).


Section I. A horizontal angle of 35° 30' is turned to the right, or west-
ward, at this control station. The line crosses Daisy Canyon between
Stations 223 and 244, and attains an elevation of 6 100 ft. at Station
270, where Control Station No. 2 is established. This is known as
Section II. The line continues without angle to the summit of the
mountain. Control Station No. 3 is at this point, 8 300 ft. from Control
Station No. 2. This is Section III. There is an angle of 2° 28' to
the left at this point. Control Station No. 4 is at Station 550 + 66,
elevation 6 330 ft., and is the limit of Section IV. A horizontal angle
of 10° 48' is turned to the left to Station 685 + 63, at an elevation
of 3 625 ft., the site designated for the discharge terminal, which
adjoins a spur of the narrow-gauge branch of the Southern Pacific
Railroad, terminating at Keeler, Cal.

The rugged nature of the topography is shown by Figs. 3 to 14,
as well as by the plat of the survey. At the time the survey was made
there was great difficulty in reaching the points traversed by the line.
In numerous cases, when the survey parties were working in deep

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