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The "floating off" of a dam is, in the writer's opinion, a fanciful
expression rather than a serious possibility. He has yet to learn of
an actual case of floating of a dam on either water or soil. I^ever-
theless, he does not mean to belittle the possibilities and effect of
uplift pressure, as is shown by the load assumptions set forth in
Table 3 under the ''most severe conditions within limits of reason."

Again, Mr. Moore states that the water assumed to flow over the
intermediate spillway would not fall "well-nigh" vertically. Although
desirous of avoiding any hair-splitting discussion as to what "well-
nigh" vertically means, the writer wishes to state that the upper and



1098 DISCUSSION : reconstruction of stony river dam

Mr. lower nappes of the over- falling water were determined according to

the results of the experimentation of M. Bazin, and the tumbling
hearth mentioned (page 931) was designed accordingly. It is inter-
esting to note that Mr. Brodie in his discussion (page 1043) mentions
that his own checking gave results practically identical with those
of the writer for the shape of the new spillway crest. The same
method was used by the writer in determining the shape of the new
spillway crest as in determining the nappes of the over-falling sheet
of water at the intermediate spillway. The fact that both studies
were based on the work of M. Bazin explains the close check between
the results obtained by Mr. Brodie and by the writer.

The real value of the use of the brittle steel pins as flash-board
supports is no longer a matter of doubt; the results of three seasons
of operation speak for themselves. Thus far, the pins and flash-boards
have allowed the undisturbed and safe utilization of the 25% addi-
tional capacity of the reservoir made available by the use of the flash-
boards. The writer does not pretend that any and all brittle steel
pins will accomplish such results, but does believe that merit is justly
attributable to the pins adopted in the present case.

In addition to the foregoing, certain scattered comments appear
to be appropriate to round out the closure of the discussion :

Mr. Finch very properly emphasizes the advisability of paying more
attention to the architectural treatment of dams, etc. (page 1029).
In this the writer entirely agrees, even though special treatment was
not necessary or warranted in an isolated location like that of the dam
under discussion. The type of treatment, of course, had been fixed
before the writer's arrival on the scene. It is noteworthy, however, that
the construction of a second spillway gave a balancing effect, especially
to the down-stream view of the dam, which the original structure
entirely lacked.

With reference to Mr. Downs' discussion of the coefficients of fric-
tional resistance of Appalachian materials (page 1036), it is well
to remember that though the tests showed an average coefficient of
0.61, the designs were actually based on a probable coefficient of 0.33,
and that it is designed to be safe for a coefficient of 0.25, without
reliance on the shearing resistance of the clayey soil.

On the several questions raised by Mr. Dunham (page 1039), the
writer is unable to shed any light. Most of the questions do not
fall within the scope of his investigation, and it is not believed
to be appropriate to extend the present discussion by a consideration
of the possibilities of imitating Nature's regulation of the flow of
streams. The use of the increased flow of the river for power pur-
poses was not contemplated.

Mr. Gregory expresses concern as to the advisability of placing
tar-paper in the joints of a dam (page 1060). In the case of this dam.



discussion: reconstruction of stony river dam 1099

this material was not expected to be permanent, and it is believed that, Mr.

as the tar-paper gradually disappears, in years to come, it will simul- Scheidenheim.
taneously be replaced by sediment and accretions resulting from the
action of the reservoir water on the concrete, particularly the alkaline
elements thereof.

It was economy that dictated the use of such an expedient as
tar-paper; yet its immediate effectiveness appears to have been as
great as one could expect from any other method. The leakage
through the joints has actually become negligible, and that, of course,
is the result sought. A leakage proportionate to that reported by Mr.
Gregory as having existed at the Ashokan Dam (page 1064) would
have been intolerable at Stony Eiver, in view of the relatively small
reservoir capacity available in the latter case. It is interesting to
note that the initial daily leakage at the Ashokan Dam was approxi-
mately one-quarter of the total storage capacity of the Stony
• River Reservoir. Possibly the reduction in leakage in the former
case has likewise been due to sedimentation; such an effect has fre-
quently been observed by the writer.

The percentage of "plums" specified in connection with the Class C
concrete was intended to fix a maximum limit, and does not represent
an average of the quantity actually used. As a matter of fact, a
maximum limit need hardly be fixed. At any rate, the writer agrees
with Mr. Jorgensen that 20% of "plums" represents a very high aver-
age (page 1071). The writer does not know the actual quantity of
"plums" placed in the Class C concrete at Stony River.

The mathematical solution presented (page 1076) by Professor
Church, for determining portions of curves showing "discharge over
spillways", such as used in Figs. 12 to 15, is indeed most interesting,
utilizing, as it does, methods of attack in which Professor Church
is a past master.

Unfortunately, quantitive measurements of leakage were not made
on May 25th and JSTovember 1st, 1915, as referred to by Mr. O'Shaugh-
nessy.

Mr. Justin offers an alternative suggestion for combining means
to increase resistance to sliding and to increase the length of the
path which leakage water from the reservoir must follow. The essen-
tials of these means are shown in Fig. 39. With reference to the first
phase of the suggestion, it may be said that preliminary studies along
the same line, namely, of increasing the weight of superstructure
(page 959), showed that nothing short of a complete filling of the
available space with masonry or concrete would suffice. Of course,
the considerations regarding overloading of the foundation soil at
the toe were applied to the base as actually, and materially, widened
by the building of the new toe-wall. Had the expedient of increasing
the superstructure weight been adopted, it would naturally have been



Scheidenhelm



1100 DISCUSSION : EECONSTRUCTION OF STONY EIVER DAM

Mr. advisable, as Mr. Justin suggests, to place the added weight as far up

stream as possible. Unfortunately, however, the slope of the deck
would have precluded obtaining any material advantage thereby.

A similar method of transferring the load from the buttress into
the toe-wall was actually used in the reconstruction in connection
with the special work at the outlet gate bays (see Plate XIII).

As to the lengthening of the path of travel of leakage water, the
writer believes that reliance may be placed on this method more
safely in the case of gravel or sand foundations than where loam and
clay are involved, as at the Stony Eiver site. It should also be noted
that the corresponding widening of the base of the dam, assuming an
entire absence of drainage openings through the base, would increase
the allowance necessary to be made for uplift pressure.

In the case of the suggested up-stream concrete apron, absolute
water-tightness would be imperative, and therein, the writer believes,
would lie the greatest difficulty, especially if the apron were made only
6 in. thick. Furthermore, the original cut-ofi wall is much less
pervious than the soil which would underlie the suggested apron.
Consequently, the result would probably be a gradual accumulation
of water under pressure under the apron, with resulting decrease in
the efficacy of the expedient. This would be true even if the reservoir
water could penetrate under the apron only at its up-stream edge.

Although it was considered well worth while to make the expensive
addition of anchoring walls to the original structure, it should be
remembered that the same results could have been obtained much
more easily and economically had a combination of anchoring wall
at the heel and of cut-off been constructed as a part of the dam at
the very beginning. For a case of original construction, therefore, the
advantages of using the principle of anchoring walls are even more
apparent.

The West Virginia Pulp and Paper Company is following the
praiseworthy course of having annual inspections of the dam made
by an experienced engineer; moreover, there is the additional safe-
guard of daily inspections by a regular attendant.

In conclusion, the writer wishes to express his satisfaction with the
magnanimous approval contained in the discussions by Mr. Coburn,
Chief Engineer of the Ambursen Company, and by Mr. Wegmann,
who had been retained in an advisory capacity during the period when
the original construction of the dam was under consideration.



AMEEICAN SOCIETY OF CIVIL ENCmEERS

INSTITUTED 1852



TRANSACTIONS



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



Paper No. 1398

FINAL REPORT

OF THE SPECIAL COMMITTEE

ON CONCRETE AND REINFORCED CONCRETE*



With Discussion by Messrs. A. H. Rhett, William Fry Scott, Carl
Gayler, H. V. Hinckley, Henry T. Eddy, C. A. P. Turner, F. E.

TURNEAURE, AND A. N". TALBOT.f



To THE President and Members of the

American Society of Civil Engineers:
Gentlemen. — Your Special Committee on Concrete and Reinforced
Concrete herewith presents, as its Final Report, the result of the joint
efforts of its own members and of the representatives of other Societies
appointed for the same purpose.

Respectfully submitted,

Joseph R. Worcester,.

Chairman,
Richard L. Humphrey,

Secretary,
J. E. Greiner,
W. K. Hatt,
Olaf Hoff,
Robert W. Lesley,
Emil Swensson,
Arthur IST. Talbot.
ISTovEMBER 17th, 1916.



* Presented to the Annual Meeting, January 17th, 1917.

t Discussions on this report, by Messrs. L. J. Mensch, G. S. Bergendahl, and
E. S. Martin were printed in the October, 1917, Proceedings, but are not published
here because the Committee has not had sufficient time to consider and reply to them.
These discussions, together with any reply the Committee may make, if so ordered
by the Publication Committee, may be published later. It seems desirable, however,
to publish the report in this volume, otherwise its publication would be delayed for
a year.



1103 CONCRETE AND REINFOECED CONCRETE



FINAL REPORT

OF THE

JOINT COMMITTEE ON CONCRETE

AND REINFORCED CONCRETE



Preliminary Draft Prepared and Submitted by the Secretary,

October 27th, 1908.

Amended and Adopted by Letter-Ballot of the Committee,

December 20th, 1908.

Revised and Brought Up to Date, November 20th, 1912.

Final Report Adopted by the Committee, July 1st, 1916.



AFFILIATED COMMITTEES

of the

American Society of Civil Engineers,

American Society for Testing Materials,

American Railway Engineering Association,

Portland Cement Association,

American Concrete Institute.



July 1st, 1916.



OONCEETE AND EEIXFOECED CONCRETE 1103



CONTENTS



CHAPTER PAGE

I. Introduction 1106

II. Adaptability of Concrete and Reinforced Concrete. .. . 1109

1. Uses 1109

2. Precautious 1109

3. Design aud Supervision 1110

4. Destructive Agencies 1111

a. Corrosion of Metal Reinforcement.

h. Electrolysis.

c. Sea Water.

d. Acids.

e. Oils.

/. Alkalies.

III. Materials 1113

1. Cement 1113

a. Portland.
h. Natural.

c. Puzzolau or Slag.

d. Specifications.

2. Aggregates 1114

a. Fine Aggregate.
h. Coarse Aggregate.

3. Water 1115

4. Metal Reinforcement 1115

IV. Mixing and Placing 1115

1. Proportions lllo

a. Unit of Measure.

l. Relation of Fine and Coarse Aggregates.

c. Relation of Cement and Aggregates.

2. Mixing 111



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