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Facilities for small-scale experimental work: Constant-head supply tanks

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length of building and a yanavi ve the second as well as the first story experiments.24

3 compartments for supplying wu, ovn

cubic feet per second, respectively. Third floor: One small constant-head tank of 2

compartments for supplying up to 10 cubic feet per second each.25

20 Test pits very few, borings inconclusive. The term "firm” rock, as used by the Bureau staff in designating the character of the rock upon which they propose to rest the
foundations of the building, is misleading. This rock, classified as "firm," is a decomposed granite similar to the overlying decomposed material, but slightly harder, as indicated
by greater resistance to penetration by the drill. The two deep test

pits were refilled before I had opportunity to personally examine the material in situ. I desired opportunity
to examine it in conference with Doctor White or other experts from the United States Geological Survey. I have conferred repeatedly with Doctor Stratton about foundation
conditions found at the present Bureau buildings built under his supervision, and have studied supposedly similar material at excavations in the vicinity. Samples, taken at the
elevation of this so-called “firm” rock, after having been exposed to the atmosphere a few weeks, present only slightly different characteristics from the so-called decomposed rock
at 8 or 10 feet higher ele tion. Samples from both elevations are readily crumbled in one's fingers, and present a more or less granular appearance. In no case does it appear that
foundations as proposed by the Bureau staff, will reach really “solid” rock that is not more or less decomposed. It appears from inspection of near-by quarries in this vicinity, and
information from engineers and architects acquainted with the material, that the underlying rock below the layer of decomposed material, is broken into relatively small, irregular
sharp-edged blocks with fault planes running in all directions. That these blocks of rock may be subject to movement along cracks and joint planes, is indicated by experiences at the
new power house. The Bureau's plant engineer states that the power house is founded on this so-called "solid” rock, movement of which has already caused serious cracking of
the floors and walls near the east end of this building, such that he believes an overlying cushion of the decomposed rock gives better support. This decomposed rock is a rather
dense, closely packed material capable of supporting more than ordinary earth material. It is not subject to slippage. One should not be misled by a casual inspection of the
natural ground surface which is a clayey loam and quite slippery when moist. In view of the above conditions it seems logical and wise to keep the foundations on a cushioning
layer of the decomposed rock, and that any expense involved in carrying the foundation walls 10 to 15 feet deeper than the structure itself requires, is a needless waste of money that
is very urgently needed in the building and equipment.

21 The ground covered by the Bureau is shown by size of trees to be in the same state (free of dumped material) as when Bureau of Standards was established. The weight
removed by excavation to foundation bottom will be greater than that imposed by the new structures; therefore, no settlement is to be feared, if bottom course is properly placed.
Actual load on earth in nearly all places will be smaller than it has carried for perhaps thousands of years. The concrete foundation walls of J. R. Freeman design to be specially
reinforced for distributing loads. Concrete foundation walls contain a very large amount of reinforcing steel designed to cause them to act as strong girders in distributing the load,

22 Open access for research,

23 J. R. Freeman regards it highly desirable that the large centrifugal pump be so placed and so provided with windows for observations on cavitation and turbulence that it can add
important practical knowledge helpful to the theory and improvement of such pumps, and regards it extremely desirable that the detailed design of the large pumps be deferred
for a year or more until researches can be made with small-model pumps, analogous to those made on models of ship propellers, which are resulting in great improvement in

24 It is proposed to provide several portable individual, self-contained, constant-head tanks and measuring weir boxes, with pump and supply reservoir combined. These units
can readily be moved by crane to any desired location. Constant-head tanks of a permanent nature can be provided at any time if it is found desirable, much the same as those
proposed in the Bureau design,

25 It is understood that one or two of the individual constant-head units (self-contained and portable) as proposed by John R. Freeman, are being considered as desirable pieces
of equipment. One undesirable feature of the layout of permanent constant-head tanks as proposed in the Bureau design is that when the units in the third story are being
used, one or more of the compartments of the second story constant-head tank are rendered more or less useless for experimental work because of the fact that they are used as
supply basins for the third foor pumps,


It seems plain to John R. Freeman, from inspection, that the Bureau of Standards' design No. 2 per plans of February 3, 1931, contained so much more concrete and intricate form work, that it will be more costly (possibly $50,000 in excess of John R. Freeman's design No. 4), and therefore that it will have to be cut greatly from plans as sketched on February 3, thereby rendering the laboratory of the Bureau's design still more inferior in capacity for large-scale fundamental research to the John R. Freeman design.

Both of these deflectors are actuated by handles not shown.

500 c.f.s

El. 290





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FEBRUARY 17 (calendar day, FEBRUARY 26), 1931.-Ordered

to be printed

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