Transactions of the American Society of Civil Engineers

A comprehensive Symposium on the conformity of model to prototype behavior has been in the minds of the Executive Committee of the Hydraulics Division for a number of years. The Committee on Hydraulic Research (J. C. Stevens, M. Am. Soc. C. E., Chairman), appointed in April, 1934, has announced this subject as one of its major interests (1), and the present Symposium is the result of the efforts of Subcommittee 2, comprising Clarence E. Bardsley, M. Am. Soc. C. E., and Joseph B. Tiffany, Jr., Jun. Am. Soc. C. E., with E. W. Lane, M. Am. Soc. C. E., as Chairman. Credit should also be given to Paul W. Thompson, Assoc. M. Am. Soc. C. E., and Herbert D. Vogel, M. Am. Soc. C. E. Lieutenant- Co lonel Thompson succeeded Colonel Vogel on the committee and was in turn succeeded by Mr. Tiffany.

Some of the general factors involved in making model-prototype comparisons of hydraulic structures are mentioned in this paper. Reasons for desiring comparisons, the types made, the difficulties encountered, and the measurements and instruments required are discussed briefly. Citing two of the comparisons made by the Bureau of Reclamation as examples, an account is given of a small irrigation structure, and of the pressure and discharge tests on the 102-in. river outlets of the Grand Coulee Dam in the State of Washington.

Other papers of this Symposium describe studies in which the analyses of model and prototype data could be based upon direct quantitative comparisons. This paper will be devoted to a study wherein, due to the lack of certain measurements in the prototype, the comparison of model and prototype performance was approached from an inductive standpoint. The problem under investigation was the unsatisfactory operation of pumps used to drain a large dry dock; the medium of study was a 1: IO-scale model constructed at the Waterways Experiment Station.

A lock and dam, one of the major projects constructed on Tennessee River by the Tennessee Valley Authority (TVA), was designed in 1934. A model of the proposed lock was built and tested at the U. S. Engineer Sub-Office, Iowa City, Iowa, for the purpose of aiding in the hydraulic design of the filling and emptying system. As the Tennessee development continued, other locks were designed and models were used to study special problems and to check the final plans. The question of the reliability of hydraulic lock models in simulating conditions which would exist in the full-size structures developed with the increased use of this method of design.

The principal hydraulic model tests of the dam outlet works (34), which included flow through the intake tower, penstock turbine, and outlet-valve manifolds, were made on a 5⅝-in. (1 : 64 scale), extremely smooth, sheetmetal model which had a friction coefficient of f = 0.021 at a Reynolds number R of 80,000 and used a maximum of 2 cu ft per sec of water. Performance and efficiency tests of the 30-ft diameter prototype, utilizing a maximum discharge of 20,000 cu ft per sec with measured velocities up to 90 ft per sec and at a Reynolds number of from 40 to 70 × 10⁶, made it possible to obtain data from which various hydraulic features of the model and prototype could be compared.

The determination of discharge coefficients for the dam spillway crest gates 8^a is described in this paper. Actual coefficients calculated for the gates from records of their performance during the flood of January and February, 1937, are compared with the coefficients predicted from tests made on a 1 : 72 scale model by the Bureau of Reclamation. This comparison indicates that the coefficients predicted by the model average 3.9% larger than those actually measured on the dam during this period.

The main hydraulic features pertaining to the design of Bonneville Dam, in Washington and Oregon, were studied by models in the Bonneville Hydraulic Laboratory. (This laboratory was located at Government Moorings near Linnton, within the City of Portland, Ore., from December, 1933, to January, 1937; hence, it is sometimes called the Linnton Hydraulic Laboratory. It was later moved to the Bonneville D am site.) Among these features were the hydraulic characteristics of the 50-ft by 50-ft crest gates with water flowing beneath them (40), and the hydraulic effect of departures of the profile of the constructed dam from the design profile.

A comparison between a series of current-meter measurements of discharge over a dam on a midwestern river and tests of a 1 : 12 scale model of a section of the dam is presented in this paper. Prototype heads covered by the measurements range d from 1.7 to 6.3 ft, and discharges ranged from less than 2,000 to nearly 16,000 cu ft per sec. Eleven of the twenty-three discharge measurements were made while the dam was submerged. Submergences ranged from less than 12% to nearly 90%.

The model study involved the development of an effective plan for improving the navigation channel of the Mississippi River between Mile 75 and Mile 80 above Cairo, Ill. At Mile 84.0 the Mississippi River enters a rock gorge, the bluffs of which confine the flow of the river to Mile 79.5. At the latter point the rock bluffs on the left bank of the Mississippi River recede, allowing the river to widen and to divide its flow between Grand Tower Island chute and the river channel along the right bluff line. The natural tendency of the river is to follow the chute channel. However, because of the more satisfactory navigation conditions that would prevail if the river could be made to develop the crossing to the right bluff line at Mile 79, two pile dikes were constructed in 1939 from the left bank at Mile 79.5 and Mile 79.2.

The new lock and dam here considered is located on the Monongahela River. Because of local conditions, the structure, as originally designed, was subjected to adverse currents that had an effect on the maneuverability of river vessels in the upper approach to the locks. At moderately high stages, the main currents, after sweeping around two comparatively sharp bends upstream, followed the lock side of the river, increased in velocity as they reached the upper approach, and then swung sharply across the lock entrance toward the center of the stream before discharging over the spillway section.

Senior Civ. Engr., U. S. Engr. Office, Wilmington, N. C.

Associate Engr., U. S. Waterways Experiment Station, Vicksburg, Miss.

The seismic method of subsurface exploration was used extensively by the Corps of Engineers, U. S. Army, in preliminary studies of the St. Lawrence River Project in the International Rapids Section. A well-defined interface between the glaciated rock and the overlying till made possible the determination of the depth of overburden with satisfactory accuracy. Considerable success was also attained in determining changes in the overburden. The program included tests in both quiet and swift water, for which special apparatus and methods were devised. The use of the seismic data enabled the design of concrete structures, navigation channels, and hydraulic cuts to proceed more rapidly than if exploration consisted only of drill holes.

Kutter's formula is widely used in computations involving the hydraulics of sewers. The value of the coefficient of roughness, n, in this formula can be determined for sewers by only one method–making actual measurements of velocities (or discharges) and depths of flow in the sewers. The results of measurements made in pipes and conduits carrying clean water cannot be used for sewers without modification: however, they do afford a valuable guide. Unfortunately, records of determinations of the value of n for sewers are all too scarce. This paper presents the results of certain determinations, based on field measurements, of the value of Kutter's n for sewers partly filled.

The creation of sewage treatment projects is limited, in this paper, to organizations established for the single purpose of sewage treatment and having this limited objective. Methods of financing sewage disposal projects are discussed with special reference to revenues from service charges and to loans secured by the revenue. The fundamental considerations in the computation of a charge for sewage disposal service relate to the three principal kinds of sewage for which the service is rendered–sanitary or domestic sewage, storm water, and trade waste. Methods of evaluating these services in terms of a rate of charge and some reference to court decisions and commission rulings are included.

The physical properties of structural steels usually prescribed by specifications are the strength and the ductility. It is reasonable to infer that, if certain physical properties are prescribed, there must be some quite definite relation between these properties and the behavior of structural members. The purpose of this paper is to discuss this relation and to raise the question as to whether or not there are other characteristic s of the material that should be considered.

This paper undertakes to report on certain progressive developments in applied hydrology, now a recognized field of engineering, and the science of meteorology, heretofore primarily associated with the prediction of weather and with the generalized influences of weather on the climatic regimes of a region. Inadequacy in the quality, extent, and length of precipitation records has given incentive and justification to the development of more rational design techniques so that the flood to be accommodated by a structure may bear a direct relation to type and magnitude of the storm that will ultimately produce it.

The first part of this paper reviews the causes of building settlements, and summarizes what soil mechanics has to offer as a basis for the design of building foundations. In the second part are described the foundations of two large office buildings in Boston, Mass., which were designed specifically for the purpose of reducing total and differential settlements to a tolerable amount. The settlements of these buildings are compared with those of other large buildings designed without the use of soil mechanics. The methods of reducing existing differential settlements are not discussed. The success of any method such as underpinning, the application of additional load to the lighter sections of a structure, the provision of continuous jacking arrangements, or the method of “bleeding” the underground by means of borings adjacent to and under those parts of a structure that have not settled are dependent on accurate observations of the behavior of the structure which is to be remedied.

Formulas for strains and stresses on planes oblique to direction of principal stresses are developed in this paper. The thesis is offered that stresses are limited to tensile and compressive stresses; that shearing stress and shearing strength are misnomers; that shear is resisted by simple diagonal tensile and compressive stresses; that ruptures or failures occur when material is overstressed in tension; and that all failures in the field of engineering structures (except where plastic flow is classed as a failure) are tensile failures.

A method of computing the size of air vent needed for aeration of spillways, based on all of the available data, is presented in this paper. The effect of insufficient aeration on the reduction of pressure beneath the nappe and on the discharge is discussed. Formulas and diagrams for calculation of these effects are included.

Covered concrete storage reservoirs can be designed by a “vertical-beam” method that offers advantages over conventional types. The method, which is presented herein, utilizes side-walls constructed as simple vertical beams with supports arranged at top and bottom to resist the internal horizontal pressure. The designation “vertical beam” is taken from this wall construction. With such a design, all of the concrete in contact with the contained water is in compression. Simple methods are afforded for minimizing temperature and shrinkage stresses. These features reduce the formation of cracks on the interior face of the structure and thus, by preventing seepage into the wall, increase the resistance of the structure to deterioration. These advantages are obtained without increase in construction cost over conventional types.

The purpose of the project discussed herein was to make careful flow measurements under laboratory conditions, to record, and to study the phenomenon of flow around a stable curved channel. An open channel, 18 in. wide and 10 in. deep, was built of transparent pyralin sections so they could be fitted together in combinations of tangents and curves. Motion pictures were taken of the flow phenomena as indicated by objects floated on the water surface, dragged or rolled on the stream bed, or held in suspension. The latter was accomplished by use of drops of a mixture of n. Butyl Plithalate and technical Xylol, colored with a deep red oil dye and having the same specific gravity as that of water.

The basic theory of turbulent flow has been applied successfully to explain the observed vertical distribution of suspended matter in streams in which the suspended load is in equilibrium with the bed material. This paper presents the results of studies made in an effort to extend the theory to explain the concentration changes in a stream or settling basin under nonequilibrium conditions. The general differential equation expressing the concentration changes during turbulent sedimentation in an infinitely wide stream is derived, and the complete solution for a certain simplified case is presented. Evidence of the validity of this solution is provided by the results of experiments which are described herein.

The engineering features of the Queens Midtown Tunnel, including its function from the standpoint of automotive transportation, its planning, design and construction, are discussed. An attempt has been made, within the permissible limits of space, to emphasize certain features of the project which presented more than the usual problems.

In the design of a base slab it is common practice to assume the reaction distribution and compute bending moments by statics, or by elastic theory if the slab is part of an indeterminate frame. In the latter type of case, fixed-end moments and stiffness values are computed as for an ordinary beam or slab with fixed lo a d distribution. The object of this paper is to develop a method of analysis which takes account of the effect of the rigidity of the foundation upon the reaction distribution. The base slab extends between two vertical walls to which it is rigidly connected.

In 1940–1941, hearings followed a petition to the U. S. Supreme Court by the State of Illinois for a temporary increase in diversion from Lake Michigan. The inquiry was directed to ascertain the effect of odors from a large pool in the heart of Joliet, Ill., on health, the remedial measures available, and the condition of the sewage treatment works of The Sanitary District of Chicago. The Special Master held that no menace to health was proved and that no remedial measures were available as effective or as promptly as the proposed completion of the sewage treatment works of the Sanitary District. The U. S. Supreme Court denied the petition.

Seasonal differences in storm types are typical of New Mexico and Arizona. Summer storms ordinarily are of small areal extent and are characterized by high-intensity rainfall in a well-defined pattern with relation to time. Winter storms cover large areas and usually are of low intensity. In this paper, results of frequency analyses of one-day rainfalls are presented for all stations in New Mexico and Arizona, the records of which exceed 15 years in length. The relation of rainfall frequency to geographic position and topographic relief are discussed, and recommendations are made for the use of these data for design purposes.

The research of which this paper is a part comprised a study of the phenomena associated with the combining and dividing flow of water in open and closed conduits. The paper is concerned only with the open-channel problem, in which the variables involved are so numerous that only an empirical solution seems possible. The conformity of actual behavior to theory is discussed, and an empirical solution is included which may be applied to rectangular channels. For other prismatic channels or for natural streams, the flow characteristics at the junction are best determined by models controlled in an hydraulic laboratory.

The principal purpose of this paper is to present a simplified general method of analysis for solid-barreled skewed reinforced concrete rigid frames and arches which can be understood readily by capable designers who know something about the theory of elasticity, without necessarily having made a special study of the subject of skewed arches. All unnecessarily complicated terms and expressions have been avoided, particularly those resulting from the solution in general terms of simple simultaneous equations which can be handled more easily by the direct substitution of numerical quantities.

Since the inception of the sewage treatment program, The Sanitary District of Chicago, Ill., has conducted many investigations on the dewatering and drying of sewage sludge. This paper is concerned with these investigations, particularly the results and conclusions as applied to the Southwest works.

On the background of a description of the waterway system that serves the navigation needs of Chicago, Ill., the author describes the development of a bridge type that serves the peculiar local requirements. The evolution of the movable type of bridge is traced through several phases, including the early “jackknife,” the vertical lift, the rolling lift, and, finally, the various developments of the bascule type.

The principal phases of the problem of reservoir sedimentation are reviewed in this paper, including (a) the origin and nature of sediment, (b) its transportation to and through, or deposition in, the reservoir, and (c) remedies for reservoir silting. Quantitative study of sedimentation rates may be made from several approaches, none of which are sufficiently developed to permit more than approximate estimates of probable sedimentation rates. Such estimates may be of use to design engineers, who must allow for inevitable depletion of storage, but the real solution to the problem, both from the technical and social viewpoints, seems to lie in the prevention of sedimentation, and conservation of the available storage to the greatest extent possible.

Common forms of the hydraulic jump in sloping channels have been classified into three general cases, and an analysis is presented which leads to a practical method of computing the dimensions of the jump. Satisfactory agreement between analysis and experiment was obtained from laboratory tests on a channel with a I on 6 sloping floor. Conclusions drawn from this investigation indicate that experiments on other slopes might eventually yield a satisfactory treatment for hydraulic jumps on any slope within the practical range.

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Techniques and equipment for undisturbed sampling of soil, laboratory testing of such samples, the mechanics of applying the results of laboratory tests to engineering soils problems, and field observations of the effectiveness of the solution methods through the behavior of full-scale structures have frequently been considered as separate entities. They should not be so considered because each is a series of links in a chain which must reach an anchor or end result to achieve its purpose. Undisturbed sampling and laboratory testing have as their prime objective the prediction of how natural soil deposits will behave under proposed loadings. The purpose of this paper is to explore one link in this section of the chain–namely the extent to which laboratory test results approximate the physical properties of soil in natural deposits.

The purpose of this paper is to present the results of certain hydraulic investigations and rainfall-runoff gagings for improved urban drain age areas of different sizes and types of development, to analyze data from these results, to develop hydrographs of runoff for areas of various sizes, development, and times of concentration, to present methods of computing runoff for use in design offices, and to compare actual values of runoff with those computed by these methods. Much of the complete research, upon which this paper is based, has been placed on file for reference in Engineering Societies Library.

The rôle of the land discussed in this paper is that which determines, from any specific precipitation period, the stream-channel inflow, which will result directly therefrom, and which will occur during or immediately following that period. Stream-channel inflow of normal ground water, from the water table, is not discussed in detail. This paper recognizes that this “role” is not a matter peculiarly related to “flood” periods, but that the land effect during flood periods is merely a special case of its effect during any ·period of precipitation.

Slender beams loaded in the usual manner t end to fail laterally at stresses often far below the yield point of the material. This fact is provided, for in design specifications by reducing the basic allowable stress in the extreme compression fiber for beams in which the ratio of length to width is greater than a prescribed maximum. The specified reduction is based more or less on semi-empirical considerations rather than on strict analytical study. In this paper the ultimate strength of slender beams is determined by rational methods similar to those generally accepted in column design, due consideration being given to highly probable imperfections in loading and beam shape.

Development of low alloy steels and high-strength aluminum alloys, and their utilization in structures, have called the attention of engineers to the somewhat lower ductilities of these materials, as compared to carbon steel, and also to their generally higher ratios of yield strength to ultimate strength. Apprehension has been felt that these differences in physical properties would. affect, unfavorably, the distribution of stress in members built of these materials, especially a t connections. This belief is reflected by the fact that, in some instances, organizations responsible for design specifications, both in the United States and abroad, have set an upper limit for the ratio of yield strength to ultimate strength.

In the fall of 1939 the Vicksburg Engineer District was forced to construct a setback levee along the south bank of the Arkansas River near Pendleton, Ark. At one point the proposed levee, known as the Pendleton New Levee, crosses Lake. Lenox, a shallow body of water which was formerly the channel of the Arkansas River. Foundation investigations revealed that the levee would be underlain by extremely soft clay at the lake crossing. Calculations of sections required to insure stability showed that the most economical procedure would be to displace the clay. In view of this fact, construction of the levee p resented an excellent opportunity for securing data concerning a foundation failure.