warpi- 1. r a. 0’3 U f u. < “MOP? .L .. .i‘lvf-Ir .150th .. mum? ‘ mm»! M. n i .. uh: :14: six MU. Fr .5 Manx.) may 1.5; .u. bf, mm. 3 2.? , ,, . . a. 0. lanthanum STRUCTURAL PROBLEMS IN THE DESIGN OF A thesis submitted to the faculty of MICHIGAN STATE COLLEGE OF AGRICULTURE AND APPLIED SCIENCE BY Howard James mkel a candidate for the degree of MASTER OF SCIENCE 195.15 PREFACE Through the courtesy of the Allied Engineers, Incor- porated, an organization associated with the Consumers Power Company, Jackson, Michigan, the basis for the ac- tual design contained in this thesis was furnished. This consisted of a map of a preposei location for a low—head power deveIOpment, and certain data relative to stream flow and foundation conditions. This material was fur- nished by Mr. Edward M. Burd, Civil and Hudraulic Engineer. The writer is also greatly indebted to Professor C. L. Allen, head of the department of Civil Engineer- ing, Michigan State College, for his supervision of the preparation of this thesis; also to Mr. Wylie Bowmaster and Professor U. W. Hitchcock for helpful advice and contributions to the material. Howard James Berkel East Lansing, Michigan June 1953 333908 Chapter Chapter Chapter Chapter Chapter Chapter TABLE 93 CONTENTS 1. The Development of Hater Tower in the United Stat03_-_-_-- ....................... 11. The Present Status of Hater POWiI [4. n Michigan 111. Plant Description 1V. Head Hater Central anu Accessories-—--—-- V. The Design of Dan, Core Jall, and Appurtenances V1. The Design of the Power House--- --------- - I t. I I". vi; as... “in 'i-i‘r epic-2‘41 (:1 O) C3 1.1:. CHAPTER 1 THE DEVELOPMENT OF WATER POWER IN THE UNITED STATES Records dating back to the time of the ancients give the first evidence of the use of water power by crude de- vices for purposes of irrigation, and for the performance of other various rather simple applications. Some forms of float wheels, constructed of bamboo, are still in use in China, while other very crude wheels, constructed of tim- ber, may still be seen in other foreign countries, having been preserved for their historical interest. The coming of the breast, overshot, and undershot wheels marked a distinci’advance over the more primitive types. These were, in effect, gravity wheels and effic- iencies ranging from 30% for the undershot, to 80% for the overshot, were not uncommon. The development of the hydraulic turbine in the middle of the nineteenth century revolutionized the use of water power and resulted in the superseding of the overshot wheel. The overshot wheel, even though it had a relatively high efficiency, was limited in its use to heads somewhat below 50 feet. The periods between the middle and the end of the nineteenth century saw the development of the American, or mixed, or inward-flow turbine in America, and small developments were superseded by those utilizing single heads over 20 feet. Soon after 1890, the use of the i 2. American wheel developed to such an extent that our own wheel manufacturers were building wheels of the reaction type to be used for heads of 500 feet and more. The impulse or Pelton wheel was developed and used efficiently for high heads, especially in the West. From 1900-1910 greater speed and power were obtained both here and abroad by the use of several wheels on a single shaft. Better wheel design and the use of vertical generator units, and more suitable thrust bearings for large units, have brought about the use of the single runner vertical units at the present time. The period of the World War, with its great boom in manufacture, caused a very noticeable increase in the de- mand for water power in this country. A contributing fac- tor was the increase in the cost of fuel and uncertainty in delivery due to labor unrest. This popularity still exists today in this country, water power possessing far greater appeal than any other form of energy generation. Hydraulic turbines are being improved constantly, and in order that efficiencies well over 90% may be obtained, great care has been given the design of such features as wheel settings, flumes, and draft tubes. Accompanying the development of water power equip- ment has been an increase in the capacity and radius of practicable transmission of power. The contrast between 40,000 volts in the year 1900, and 220,000 volts only twenty-four years later is evidence of this rapid advance. A comparisOn of the lengths of lines used in the earlier days extending distances of a few miles, and at the pres- ent time distances up to 500 miles, will serve also to 5. illustrate the extent of this progress. With regard to the present status of water power in the world, a conservative authority estimates that the potential water power available is four times the total amount of the present use of this resource. A total po- tential water power of 459 million horse power in the world, the present use of this resource is about 2 or 3 per- cent of the total potential power. Quoting from the estimates of the United States Geol- ogical Survey which states that for the United States alone, area 3,026,791 square miles, the developed horse power is 2.97 horse power per square mile, and the potential is 11.6 horse power.per squaremile. From a statement by the same authority*, EurOpe as a continent leads with 2.29 developed horse power per square mile. Yet the United States, with about .8 of the area of Europe, materially exceeds the latter with about .68 horse power per square mile of area. Most of the older plants in the United States , ex- cluding those in the middle West have been developed under laws similar to the Mill Act in New England and New York. This act stated that a power site owned by an individual or a corporation may be developed and, if necessary, flow- age made of the land or undeveloped water rights upstream. Should riparian owners refuse to sell their rights to the land or flOWage, these could betaken by right of eminent domain. In the West, a great portion of the available water * Barrows, Water Power Engineering. 4. power is located on the public forest lands. For many years it was necessary to receive congressional sanction, a slow tedious process, to obtain permits for the development of such territory since no fixed policy prevailed. President Roosevelt in two messages to Congress, one in 1908 and an- other in 1909, vetoed acts conferring franchises for the development of water power in the public lands. The presi- dent stated, " that adequate provisions for the safeguard- ing of the general public had not been incorporated in the acts, that no rights involving water power should be grant- ed to any corporation in perpetuity, but only for such length of time as to allow them to conduct their business profitably, and privileges obtained from the National Gov- ernment should be paid for by a reasonable charge." Action was taken by Congress in the passage of the amended Water Power Act, on March 5, 1921, which excluded all national parks from its provisions. The Federal Water Power Commission, whose purpose is, " to provide for the improvement of navigation, the devel- opment of water power, and the use of the lands of the Uni- ted States in relation thereto," consists of the Secretaries of Agriculture, Interior, and War. The commission is given the power to investigate the cost of water power develop- ment, its availability for market, and its fair value in any region to be deteloped, and in these duties the comm- ission is of prime importance in the development of water power in this country. Licenses are issued to citizens, municipalities, or states to construct and maintain projects for the develop- ment of navigation and for the development, transmission, Lg if 5. and'utilization of power, " (1) from or in any of the nav— igable waters of the United States, and (2) upon any part of the public lands or reservations, and (Z) to utilize the surplus water from any government dam."* These licenses are issued for a period not to exceed 50 years and prefer- ence is given to states and municipalities as far as poss- ible. The annual fee is fixed and collected by the Federal Water Power Commission and is used to cover the cost of ad- ministration of the act and as payment for the use of nation- al lands or other preperty. Such other rules and regulations not of especial significance in this thesis, may be found in complete text available for distribution in pamphlet fern. Data available up to June 1925 list 524 applications to the Federal Water Power Commission for power deveIOp— ments and more than 100 applications for transmission lines. The applications involve more than 240 million horse power. During the year 1925 alone, for example, an aggregate of 620,000 horse power in 80 applications fer power projects, and 32 for transmission lines, were filed with the commiss- ion which illustrates the extent of its activities. The super-power investigation was made during 1920- 1921 under the direction of the Geological Survey, and is reported in Paper 123. This investigation showed that, con- sidering the super-power zone as including the New England states, New York, Delaware, Pennsylvania" Maryland, there ‘was a concentration of nearly 25% of the population of the United States, having 515 electric utilities, 18 railroads, and 96000 industrial plants. Only one-fifth of the required power of this zone can be supplied by water power. Quoting * Barrows, "Water Power Engineering". 6. from Paper 125, the survey recommended, " that large steam plants be located at tidewater and on inland waters, as well as being bolstered by utilization of hydro-electric power which may be obtained from rivers in or adjacent to the terr- itory." A system of interconnected transmission lines of high voltage, involving a combined capital investment of $ 1,300,000,000, which would net nearly 3396 on the invest- ment above the fixed charges is estimated as being necess- ary to take care of the Super-power. The activities of the United States Geological Survey in making this investiga- tion have done much toward the extensive use of the feat- 'are of super-power deve10pment. '7. CHAPTER 11. THE PRESENT STATUS OF WATER POWER IN MICHIGAN The first'water power developments in the Northwest territory were small local mills patterned after those built by'the pioneers coming largely from New England and New Ybrk state. Lack of transportation was the controlling factor in all these projects. The dam, wheel, mill, and even some of the machinery were built of local resources, and the output of the mill, whether lumber or grain, was the only source of supply. This condition made the water rights and mill the prized possession of every community. Such older water power centers as'Ypsilanti, Battle Creek, Grand Rapids, All- egan, South Bend and others are evidences of this influence. Besides these larger centers, every small head on a stream was provided with a.mill site where a small amount of power was available. Most of these old mills are still in exis— tence, a few in Operation, still others being preserved for their historical interest. A few have been rebuilt into elec- tric plants. There were probably five hundred such small mills in the lower Peninsula of‘Michigan. When railroads moved raw products to the market,and finished products from the manufacturing centers on an econ- omic basis which could not be met by the local water power, the value of the water power soon declined. The coming of good roads and the increase in the number of automobiles manufactured also had their effect in permitting transpor- tation and trading over a much larger range. It was in this manner that the small local mill disappeared. t, 4. 4r 5 I O 2 I. NMrZuU o3uo 1.2.x and 5.00 #3926 WATER DOWEIZ IN MICHIGAN F77. 9. Some of these smaller mill powers were taken over and electrified because it seemed uneconomical to abandon them. Electrification of the small mill imposed many handicaps, however. Their use even in systems is limited since such systems haye a great deal of electrical capacity and a weak lizik in such a network is not permissable. For these reasons evezlthe smallest station in an interconnected system must be. equipped with the highest grade equipment. This fact was Innially prohibitive to further use of many of the small mill powers. In those cases in which this cost was met, there was needed a complete rebuilding of the power house structure, histallation of new and expensive machinery and equipment, and.the construction of a high voltage station for connection in.'transmission, was necessary. The expense caused by such an. investment, which raised fixed charges to such a figure thllt generation was no longer profitable, made such an out- lagr of capital uneconomical. It was for these reasons that mazuy of the smaller mill powers were abandoned with no fur- ther use. The present developed water power in Michigan is per- haps two-thirds of the total capacity which can economically be developed. This conclusion is substantiated by the infor- mEJZion presented in graphical form in the accompanying graph. The writer is indebted to Mr. Edward M. Burd, Engineer, Allzied Engineers, Inc., for this information which was pub- lished in the "Michigan Engineer." One of the lowest generating costs is shown by the Union Carbide Plant at the $00, an installation of 40,000 Kilowatts operating continually and with sufficient pondage by Virtue of having Lake Superior as a pond. Next in order 10. of economy, and comprising the first twenty-five percent of Michiganfis capacity would be the larger plants on the the more favorable sites. This brings the total up to around six mills per kilowatt. All Of the plants built since the World War do not produce energy as cheaply as this figure. Fbr these reasons, the best remaining hydro projects for utility operation at the present time entail a total energy cost, based on Operation at load center, on a basis compar- able to steam power, in excess of seven mills per kilowatt. Estimated total develOpments now aggregate perhaps 50% and the limit under favorable conditions would seem to be not over one and one-third cents, or 75% of the total. This es- timate would-leave the last 25% unattainable according to present standards. Or more simply put, two-thirds of Mich- igan's potential water power is at work and this is by far the best portion. The upper term of one and one-third already referred to is a.relative term, however. That is, there are other factors affecting this value. One of these is competitive power and changing values. It is also quite definitely lim- ited by utility income, as the primary sale net income at the present time of two large systems in Lower Michigan is 1.6 cents. per kilowatt hour. Some margin must also be left between generating cost and the net income to cover allow- ances for line and distribution losses, to cover the cost of doing business, return to stockholders, and a margin of profit. Primary sale contributes 50% of the whole utility disposal which gives some idea of the relatively small mar- 8111 which is left. Since the utilities develOp 8596 Of the tOtal water power output in the United States, and perhaps 11. a greater proportion in Michigan, and the rest largely is small powers already described, the economic limitations of any further development for any purpose appears evident. Interconnection of steam and hydro systems seems to present the maximum of economy in generation and also the best prospects for hydro plant development. It is very im- portant to keep the two forms of energy generation in the proper pr0portions. Some argue for the development of all hydro for the purpose Of conserving our natural resources, national economy, and the exercise of the rights Ofkhe pub- lic to enjoy these sources of apparently cheap power. Other people propose the use of steam as an alternative since it can be produced more cheaply than hydro power. The opinion of the engineer is that these two systems instead of being rivals, should more properly be classed as partners. It is in this connection that the development of this preject is undertaken, and the reasonableness of such interconnection will further be described. Near Niagara Falls the industrial district centering about Buffalo is supplied with a large amount of steam generated power. On the other hand, it is equally true that large hydro plants are being usedfin such cities as Pitts- burgh, Philadelphia, Baltimore, on interconnected systems, all favored with respect to a cheap supply of coal and cool- ing water. It is thus seen that the proportion in which to combine steam and hydro is dependent on natural laws and is controlled by elements which enter into the total cost of production. Furthermore, interconnections are now underway to bring hydro power to New York City and Washington, D. C. These 12. examples should serve to dispel the usual conclusion that hydro power can be used profitably only when steam is at a distinct disadvantage. The fundamental difference between the economies of steam and hydro generation is that steam involves a low a first cost and high operating cost, while hydro generation fl is characterized by a high first cost and a lower operating cost. Consequently, a hydro company generally expends a large portion of its gross revenue on bonds and fixed charges. The. expenditures may be briefly summarized as follows: 1. The natural factors or conditions affecting con- struction and operating costs, or what have been called the "characteristics of the site." 21 The use and market characteristics as affecting the sale price and value of the power when developed. The first item includes geological features as affect- ing the available foundations for structures, particularly the dam. Topographical conditions are also df great impor- tance in determining the dimensions of the dam, and thus largely affect the cost and the relative proportion of the fall or head to be developed by the dam or by the waterway. Storage possibilities at upstream sites are Of special im— portance. Operating cysts may also be affected by especial con- ditions which ay prevail on a given stream. For example, a stream jedt to frequent floods or high-water periods may have/the power at the dam site frequently curtailed by backwater, and such a condition will require renewal of flashboards. The presence of ice, particularly anchor ice, 15. on the streams having numerous falls, also introduces troublesome problems of Operation. Under the second item in the above summary, the charac— teristics of use and market include the conditions particu—_ larly affecting the sale price and the value of the gener- ated power. _ For example, a factor of vital consideration is the closeness to market. A water power site may be exceedingly low cost development, but situated so far from any possible market as to be out of the question as far as economy is concerned. The cost of other power at the available site and mar- ket is of great importance also as affecting the sale price Of the water power. Load factor as affecting the use ofthe power is of great importance as certain features of the_water power development particularly the power house and equipment, vary nearly in inverse proportion as the load factor. The corresponding elements entering into the cost of steam power are: ' . 1. Fixed charges on plant and transmission costs, in- cluding interest and depreciation, taxes, etc. 2. Operating costs, including fuel, labor, maintenance and repairs, and miscellaneous items. An examination of the two groups of factors given in .this comparison shows that the elements of water power cost are practically the same as those of steam cOst of genera- tion, except,tha§,tbelfuel outlay is missing as an operating expense. These elements differ greatly in amount. however. ‘14-. TO draw a conclusion, the limit in allowable cost of a water power plant is reached when its fixed charges become so large as to offset the lower operating costs which it boasts. 0n the other hand, a water power site which can be I developed at low cost has a correspondingly high value as a water power privilege, reflecting the advantage in cost of power over that of steam. A comparison between the two sources of power involves ‘then,.a comparison and a proper evaluation of the above ele- ‘ments3 namely fixed charges and Operating costs. A low-head development, such as the project considered in this design, has such a large part of its total cost in ;£fldb dam, water rights, etc,,that any additional plant capacity _will cost eomparatively little, and in fact will doubtless cOmpare favorably with equal steam cost. This may not be true, however, of high-head plants, in which incremental costs, such as the installation of additional water conduits, necessitates additional outlay. Incremental cost is not of such great significance in a low-head development, and as a result, the over development becomes economical; since little is added to the investment. The use of hydro to replace steam or to delay the system of steam construction program, just- ifies the added investment, because of the saving in opera- ting costs:and savings in fixed charges which would be nec- essary in steam plants. Since hydro generally costs more per kilowatt hour in- stalled than steam capacity, it might seem possible that hy— dro could be considered in districts where power can be gen— erated from low fuel cost. But it has been mentioned that saving is the low operating cost of the hydro power. If it 15. can replace the production cost of corresponding steam ener- gy, and at the same time, avoid the investment in steam plants that would be necessary, it is possible under many circumstances to Justify the development of water power. There is a decidedly delicate balance between the two factors of operating charges and fixed charges, the appreciation of which has been a recent develOpment.in this study. Whether a hydro plant has the ability to be servicable in replacing steam depends primarily upon the size of the system and the sharpness of the peaks on the load curves, The larger the system, the greater are the possibilities for fitting the available hydro power units into the daily or weekly load curve. Such an arrangement replaces a large amount of steam capacity. In such cases the hydro plant ef- fects a saving in fixed charges. Another type of service, somewhat more indefinite and harder to evaluate in terms of dollars and cents, is termed the "peak accomodationfl For example, there may exist in a given system, a number of old steam systems still kept in service, although uneconomical. These operatdbut a few hours a day. Some of the difficulties encountered in the operation of such units, and especially their change over to hydro power combinations, have already been mentioned. In such cases, it may be that the run—of—river hydro plants have suf- ficient pondage to regulate the total weekly pondage require- 'ment. A little less energy may be generated in one part of the week in order to conserve water for the remaining part and permit an uneconomiaal steam plant to be shut down cold for several consecutive days. This is a great aid in boiler room economy. 16. Such economy in steam operations appears to be greatly affected by boiler room economies. If sufficient pondage is available, the daily discrepencies in load estimating may be shifted to the hydro plant so that the base load system of steam plant operators know further in advance what load will be expected of them. Also when a hydro plant has been install- ed idexcess of continuous power at the time of minimum stream flow, it is possible by manipulation of pondage to utilize excess capacity to reduce the overall cost of energy. The fourth service, maintaining system frequency, can be rendered to good advantage by low-head hydro plants. Modern steam plants have a surprising ability to carry load swings but at a disadvantage. Since the water passages are long in a high-head plant, and also because of the danger of water- hammer in the penstocks, these installations are of little assistance. The low-head plant with its short water passages does not suffer this disadvantage making load changes of less consequence. The trend toward general inter-connection of power sys- tems is particularly favorable for hydro develOpment, for it brings hydro power into a field formerly occupied solely by steam. It gives hydro power the desired conditions to make possible the use of cheap incremental capacity. Interconnec- tion gives the hydro a wider market for off-peak energy that can be disposes of during times of abundant flow. " Conclusions make it almost obvious that sucessful water power development is dependent upon the opportunity of rendering a substantial service to a widespread market for power which is primarily supplied by steam."* "Power" September 1929. 17. CHAPTER 111. PLANT DESCRIPTION In the following pages, an attempt is made by the wri— ter to condense into what might be termed an introduction to the design proper, certain of the features of the devel— opment which are included in detail in separate sections. One of the unique features in connection with the pro- vision for adequate spillwsr capacity, a prime requisite for stability and security of an earth dam, is the semi—per— manent flash-board arrangement. The bottom of the spillway channel, over which the water passes, is constructed as a reinforced concrete slab resting upon two transverse walls running parallel to the center line of the dam. Running per- perpendicular to the center line of the dam are cross walls designed to support the pavement slab, since the top of the spillway is made up of a paved highway in the same manner as the remainder of the length of the dam. These slabs are de— signed to support traffic loads of considerable magnitude as it is expected that the road will be used as an entrance to the power house to be used by heavy trucks laden with equipment. The discharge channel is formed by a slab of eight inch thickness laid on a bed of Cinders to assist in the prob- lem of drainage. A tile embedded in the Cinders assists in the drainage. Attention is now directed to the design of the semi—per- manent flash-boards. Flash-boards generally consist or a series of panels supported on pins set in the masonry crest of the dam. The L_ l8. pins are designed to bend over under pressure and loosen the structure when the water in the ponded area reaches a certain elevation. In such an arrangement, the flash-boards are carr- ied down-stream by the flood water and are destrOyed. This makes it necessary that before the next period of high water arrives, a new set of flash-boards be procured and installed. This is a crude and expensive method of affording a protection. For this reason. a type of semi—permanent flash-boards is effiected in this development in which much the same type of arrangement employed in the temporary design is used ex- cept that provision is made for fastening the flash-boards. The flash—boards are constructed of cypress wood and are bolt- ed together at the top and bottom with supports of the same material. In addition, at the bottom of the flash-boards is placed a steel angle which forms a shoe on which the structure moves. At a point between the two supports determined by the method of moments, a hinge connection is fastened by means of a pin connection . This hinge acts as a pivot around which the flash-boards act. This pivot is so arranged that a rise of water in the ponded area of five feet will cause the flash- boards to collapse and occupy a recess in the bottom of the spillway floor. The steel shoe fastened to the bottom of the boards permits of easy passage across the slab which forms this floor. In order that the structure be stable and not collapse at uncalled-for times, an additional weight is pla— ced at the point of attachment of the shoe angle to care for this emergency. A recess in the timber beam,cast in the floor of the spillwam in the form of a "V" holds the structure when in a vertical position. I. This simple arrangement allows for a maximum rise in l9. water level and also affords adequate protection against over topping. It is in addition an inexpensive design and very practical since it is not necessary to replace any of the parts after an occasion of high water has arisen for the use of the spillway. The power house is here described in two sections; the substructure and the superstructure. There are two types of substructures in use in the mod— ern day design of power houses. The first makes use of a basement under the structure in addition to the provision for necessary water ways. In the second type the turbine is mount- ed on a barrel structure which permits the omission of the basement. The first type is chosen for several reasons. In the first place when a basement is provided, the generator is at floor level. Also outside air is available for the cooling of the equipment. A still more important feature of the basement is that it provides a storage place for trans- formers and other equipment such as electrical conduits and oil and water piping on the ceiling. The units are placed in a row to facilitate handling by the traveling crane which spans the entire operating floor of the power house. Two 2500 H. P. turbines are placed thir- ty two feet apart and a 5000 H. P. turbine is placed at thirty two feet from the Center line of the other turbine. These turbinesare directly excited by generators on the same shaft. The generators are on operating floor level at eleva- tion 280 feet. A stairway provides access to the auxiliary floor at elevation 271 feet. The Francis Vertical Plate Steel Cased turbines are in installed at floor level 259 feet. The L'— 20. -penstock also enters the substructure at the same elevation. These details may be referred to in the section on the design of the power house. ,The floors of the power huuse are constructed of rein- forced concrete, of the . slab construction. The width of the power house is 60 feet. This entire width is spanned by the travel of the 50 T. crane and to facilitate handling of generators, transformers and turbines, sections of floor five feet in width and almost the entire length of the power house, namely; 75 feet, are removable. These sections are construct- .ed of Blaw-Knox steel grating. This grating is constructed of flat bearing bars crossed at right angles by twisted cross bars, the intersection being made by one—piece electroforging under enormous pressure, This is done without cutting, slot- ting or punching any of the bars or removal of metal. T“is grating as employed in this design to take the place of a thoroughly reinforced concrete slab gives equal strength and rigidity. A special design is necessary to support this grat- ing at the places where the generator shaft projects above the elevation of the operating floor. This design will be furnished by the company. The design of the support and the reinforcement of concrete slab adjacent is covered in the section under "Floor Slabs.” The substructure walls are constructed of reinforced concrete. A special feature made necessary by the integral 'construction of the dam and power house, is the retaining wall as foundation for the superstructure as shown on the detail plans. This wall is designed to resist an unusual com- bination of loads, namely the load of the superstructure, or 21. the superimposed load; the load or pressure of the earth fill forming part of the dam; and lastly its own weight. The wall is constructed as a ccunterforted wall. The toe pro— jects a distance determined by design requirements, under the floor which is the lowest floor under the upstream half of "the power house. The thickness of this floor is increased considerably to allow for the application of indeterminate loads. The foundation under the retaining wall are made as supported on the same subsoil as the dam itself, namely the mudstone layers .later, referred to. The turbine setting is described on drawingp-Qfiiflm sectional view of the substructure. The entire weight of the turbine is carried through the barrel and the turbine speed rings to the foundation. The recommendations for draft tube design are usually furnished by the manufacturer who fixes the requirements. The draft tube position is located on the section view, how- ever, in its probable position. The electrical cables and conduits are placed on the ceiling of the transformer room. The ventilation of the generators is a very important consideration. The openings on the substructure of the down- stream foundation wall of the power house will provide ample circulation of cool air to the equipment. A shower room is also provided in the basement of the power house, in which room are provided also lockers and toilet facilities. The primary function of the superstructure is to support the machinery and also to provide facilities for handling 22. such machinery and equipment. The clearance of the crane, namely 7 feet 10 inches, fixes the height of the power house. In this design the height is chosen to be approximately 20 feet from the oper- ating floor at elevation 280 fret to the bottom cf the roof truss. The roof truss is of the Fink type and spans about 60 feet with trusses at fifteen feet center to center. The roof covering cons3sts of corrugated steel sleets, supported directly on the purlins. A lining made of two layers of felt and two layers of tar paper is placed directly on wire net— ting stretched over the purlins. This roof construction pre- vents condensation under the metal roofing and also acts as an insulator. The design of the roof truss is covered in de- tail in a later section. The columns in the superstructure are built of built up sections. The design of these columns is made particular- 'ly difficult since the application of the crane loads at its upper third length causes a marked tendency to bend. This load is very eccentric and causes further complications. The exterior columns are brick veneered on the outside and Natco—Vitritile covered on the inside. This type of tile installation is an extremly attractive finished face glazed structural fire clay tile. It is used throughout the power . house both for interior walls and also partitions. The tiles are carried over window openings by steel rods of specified Size embedded in concrete, which is poured in the openings in the tile. The floors of the power house are constructed of reinr fOrced concrete construction ' slab and beam design. The design is entirely orthodox in all cases and is of special type in the installation of the steel grating already re— ferred to. i The floors are to receive a dust preventive application. Doors and windows are included in the separate section of power house details. Both are of Truscon manufacture. Lighting of the power house is shown on the drawing . The type of fixture chosen for illumination of the Opera— ting floor is the dome reflector type. These fixtures are fastened at indicated intervals on the lower member of the roof truss. These fixtures disperse light in all directions and allow a minimum to pass upward into the unused portion of the roof Constructed of the open members unenoloscd. The following is a list of the equipment for which space is provided in the superstructure; Main generating machinery; Turbine machinery, governors, pumps, and tanks; Motor- generator sets; Compressed-air equipment; Water—supply pumps; l Switchboard and low-tension switches and buses; Storage batteries; Transformers, oil tanks with filter and necessary pumps; Telephone equipment; Lavatory; Office. Should space become limited in the superstructure, ample room is available in the substructure, and some of the above equipment may as well be placed in the basement. 23. H HEAD w; ER CoKlRCL are ACCESSJEIES The main purposes for which stream flow measurements are necessary are as follows: (1) To estimate the average annual energy output of the develOpment; (2) To estimate the additi nal ener y provided by a pmoposed storage reservoir; (3) To estimate the minimum annual energy output; (4) To determine the capacity of a storage reservoir M>equalize the flow during the period to a minimum; (5) To estimate the minimum daily output withuut stor- age. Considerable time was spent in making the determina- tflons relative to stream flow measurements and estimates since accurate measurements have not been taken on the Au Sable River, the river which was used as a comparison since the location cfl'the prepesed dam and power plant were not known. This eb— viously precluded that many of the results as far as maximum. tum.minimum flows be largely estimates, with the possibility that they would be largely erroneous due to the fact that they were obtained by the method of comparison. The results of this Part of the investigation, namely the comparison of the two rivers, have been included in graphical form in the accompany— ing sheets. Low flow is a4sumed to be at the stage shown on the map 0f the site contained in the pocket in the back of this the- 25. sits, and represents a discharge of about 800 second feet continually. This corresponds to a surface elevation of 245.5 feet at the boring base line. It is assumed with some basis from past experience that no greater rise than 5 feet would take place except during the Spring break—up in April, at which time the probable rise would not exc:ed 8 feet. The river flow assumptions given here were obtained through the courtesy of the United States Department of Agriculture, Division of Stream Flow Measurement, State Building, Lansing, Michigan. AVH is: '8'“ 3N1”? i 'I‘l-i _ _ a. _7__J..__. flmZu mJM(m :4 No... w>~SU wer‘m -:‘-r H lib! .EC .5“ an. .>J35 9L. .UMD flak mmZN .x. Non w>~5u Garza Inland. Illa .11 I ?I"" Gauge-height record "1' I! Date Dec. 10 ---- 3. ---- 30 ---- 4. 6.56 5. 6.30 000000000. coo-00.00000 HHHHNOHHOHIFHNOOHHNNNNNgH $GNO§®NQCNOH®OQN§NC§HNN '0 [.5 (D O 0500507005030050300305050503050‘05050‘0‘05050505 O O ‘ O (D O 0‘ 'Jan. 6.15 6.11 6.14 6.09 6.15 6.08 5.97 6.52 6.52 6.00 6.04 6.06 6.09 6.09 6.15 6.20 6.10 6.05 6.11 6.10 5.94 6.07 6.26 6.16 6.09 6.06 6.05 5.84 6.26 6.06 6.05 PART A for the Au Sable River near Red Oak, Mich. Feb. 6.04— 6.05 6.00 6.00 5.96 6.06 5.91 6.06 5.87 6.10 6.19 6.07 6.07 5.97 6.27 6.15 6.06 6.05 6.06 6.06 6.07 6.08 6.04 6.06 6.08 6.08 6.09 6.10 Additional Data: Mar . V 6.09 6.10 6.06 6.08 6.05 6.04 6.06 6.05 5.95 6.00 6.06 6.10 6.04 6.15 6.10 6.09 6.09 6.09 6.10 6.10 6.12 6.16 6.24 6.27 6.54 6.20 6.28 6.51 6.55 6.52 April 6.52 6.56 6.47 6.47 6.57 6.60 6.58 6.68 6.72 6.96 6.95 6.85 6.79 6.77 6.65 6.57 6.57 6.58 6.58 6.45 7.05 7.11 7.04 6.88 6.78 6.67 6.60 6.57 6.45 6.45 May 6.42 6.57 6.55 6.20 6.55 6.51 6.80 7.00 7.11 7.20 7.11 7.02 6.91 6.79 6.65 6.59 6.51 6.46 7.27 7.24 7.05 6.82 6.75 6.77 6.67 6.60 6.54 6.51 6.60 6.56 6.58 June 6.49 6.48 6.48 6.45 6.40 6.56 6.54 6.50 6.50 6.28 6.26 6.21 6.20 6.17 6.15 6.09 6.15 6.09 6.15 6.14 6.16 6.25 6.26 6.25 6.19 6.15 6.22 6.88 7.52 7.00 Au Sable near Red Oak Michigan between Sec.2-3. T.26N. R 1E. One-half mile South of Red Oak Post Office Osooda County. Four miles North of Luzene. Date Width Area Vel. Guage Deo.4 72.4' Jan.8 70.0' Mhr.12 69.5' Apr.7 72.5' PART B "X" sq.ft. height 261 2.62 6.56 246 2.72 6.18 228 2.67 6.06 269 5.50 6.59 277 5.26 6.64 May27 72.5i "Q" Q—‘ft. Method Coeff.Time Fact. 685 668 609 887 905 02-08 do 17 55 55 55 56 5°"? #' “ g... fiH 1% 107.8 108.0 100.5 154.5 156.0 a». ,9 50. Computations for obtaining values for "Q" for data on guage readings given in Part A: Data given in Part A are furnished through the courtesy of the United States Department of Agriculture, Division of the Interior, and represents information taken during 1931. The information given in Part B is a partial determination of the data shown in the first part. From the sample compu- tation shown below, the relationship between A. and B. is readily seen. This simple computation obviously does not give what might be called accurate results for the river in this problem, but for the purpose of establishing assumptions re— garding maximum and minimum discharges and for subsequent calculations, it is entirely satisfactory. Sample Computation: (Q7 Equation: x : Q = x' : 6.18 : 668 - 6.56 : Q' Q': 657 c.f.s. Code: x' - guage reading in Part A. Q' - discharge in Part A. x = guage reading in Part B. Q - discharge in Part B. Ill-Dill! ll ‘ TABLE g1; DISCHARGE IDate Deo.'50 Jan.'51 Feb.'51 Mar.'51 Apr.'51 May'51 June'5l 685.0 661.0 608.0 615.0 681.0 691.0 700.0 685.0 615.0 609.0 614.0 685.0 687.0 698.0 687.0 661.0 60410 610.0 697.0 784.0 698.0 685.0 615.0 604.0 612.0 697.0 670.0 695.0 670.0 661.0 60000 ----- 885.0 68400 690.0 669.0 612.0 610.0 609.0 885.0 680.0 685.0 674.0 602.0 595.0 608.0 886.0 926.0 682.0 675.0 680.0 610.0 6l0.0 910.0 952.0 678.0 671.0 665.0 59010 607.0 916.0 967.0 678.0 10 675.0 604.0 614.0 598.0 946.0 980.0 677.0 .11 672.0 608.0 669.0 604.0 945.0 966.0 676.0 12 667.0 610.0 658.0 610.0 942.0 855.0 670.0 15 660.0 615.0 658.0 605.0 925.0 940.0 670.0 14 611.0 615.0 602.0 608.0 920.0 925.0 668.0 15 610.0 661.0 676.0 662.0 905.0 905.0 670.0 16 676.0 670.0 664.0 614.0 885.0 887.0 667.0 17 615.0 614.0 610.0 615.0 885.0 875.0 662.0 18 690.0 608.0 609.0 615.0 886.0 695.0 615.0 19 660.0 615.0 610.0 617.0 871.0 880.0 662.0 20 604.0 614.0 658.0 615.0 695.0 990.0 665.0 21 658.0 598.0 612.0 614.0 960.0 986.0 665.0 22 660.0 610.0 608.0 661.0 966.0 955.0 674.0 25 610.0 676.0 610.0 665.0 958.0 942.0 677.0 24 676.0 675.0 610.0 675.0 957.0 920.0 675.0 25 614.0 675.0 612.0 676.0 955.0 922.0 668.0 26 661.0 610.0. 615.0 684.0 907.0 907.0 664.0 om-qoamnhumr-l 29 610.0 676.0 ---- 680.0 885.0 975.0 995.0 50 612.0 610.0 ---- 682.0 095.0 887.0 952.0 31 610.0 607.0 ----- 681.0 692.0 882.0 ----- The variation in the discharge for successive days,as will be noted from an examination of this table.of dischar- ges,is due to a change in factor from the data'furnished by the stream measurement department of the United States Dept. of Agriculture. The actual change in the discharge would not be so notieable because the width is the only variable of any account. See part B. .. .. ~ 0 n a . . . . u r . ) . u w .. .. . 7 . . a, . . . 4 . . . n . . x y , y . . y .5 . . . . . .. . w l . .. . n . . . .. a x . n . . y . . . i 3 A c . . 4 . .. I . , . ., . , . , . y u . . , . . 1 . I u y y . . . . , l _. y . . » . i ,. . . . . . . . . n . . V. . . 3 l . . r . . I l v o . . . . I. . In". n. .461 393 :< «on 0.. I|l|II\1. \ 81— add 00: a so :0. . .EMJQOIA 6:; Eluzu no... G 17 Km Ill UGI‘ 100.5 _ ' '04: mm; ,,, snaffle? with? .,...It , WUHSWNEO m6~_<. tow 5 20654.12er .4 ‘ Jul. .Lrn .5316 8.9 6.0 22:2 55. Pondage is defined as the holding back and releasing later of water at a dam of a water power development, (1) to equalize daily or weekly fluctuations in river flow, (2) to permit irregular hourly use of water by the wheels to accord with the fluctuations in load demand. In order to make a rather accurate and quick determination it is noted that 45,5601cubic feet will provide a flow 6f approximately 1 sec- ond foot. In order to make a similar comparison, it is necess— ary to measure the volume which can be considered to furnish pondage. For purposes of computation, the Western boundary com- prising the water shed is assumed to be located .74 miles west of the most northerly bank of the river as is shown on the Location Map; the Northern b undary as being the top mar- gin of the map; the other boundary being the irregular line formed by the center line of the dam and contour line 270 ft. This area was planimetered, that is the area between success- ive contours was planimetered and these areas multiplied by the average height or difference in elevation and the contour interval. This area as planimetered was equal to 5,782,360- square feet. This method proved a rather unsatisfactory one and a second one was devised and finally dopted. The method used consists in dividing the entire area en- CIOsed in the boundaries mentioned into 100 square foot areas ans then estimating the corner elevations from contour lines which were already drawn and then making the necessary comp- utations. This method seemed entirely suitable and was more practical since the contours were so widely distributed over the area. ...- ........ Hardy..." 31¢... .... .. .. ...? .. . .r.. ....n. .5... . _. .r. 2 ... .. .... . .Lufimwiflwwn? ..: hf... 34. The results are included in the next few pages. The ap- .proximate pondage as determined in this manner was 194,415,250 cubic feet. Now referring to the statement that 45,560 cubic feet will provide a flow of one second foot, it is seen that the pondage available at this site will only providv water for low water conditi ns, and then only as an equalizer of daily fluctuations in river flow and also will provide for irregular hourly use of water by the wheels. These results would have ordinarily been disa pointing to promoters of a proposed development, but in this case, .not only because this problem is entirely theoretical, but also because the boundaries of the water shed were arbitrar — ily chosen, did the results seem at all plausible. After the dividing of the entire area into 100 foot square areas, the elevations at the corner points were deter— mined from existing contour points and by interpolating in the cases that a contour line did not run close enough to the corner in question. The next step was to refer all these elevations to a Single plane to figure the volume. The plane used was, of course, the top of the proposed dam at elevation 501 feet. A table was constructed, a portion of which is included be- low to illustrate the procedure, in order to facilitate the work. All the possible corner elevations were listed in one eclumn and Opposite each of these, the difference in eleva- tion which such a height would be referred to the datum, was listed. Then the complete map was covered and the differencces in elevations recorded. In accord with methods already established, the corners L... , l W that appeared in one square only were multiplied by 1; those that appeared in two squares, by 2; those that appeared in three squares, by 5, and so on. The total was divided by 4 to place the result in cubic measurement. ‘Exanple: Elevation Difference in elevation between corner ‘ and datum. I 244.1 56.9 244.2 56.8 244.5 56.7 Computation: (M x 1) + (M x 2) + (n x 4) = 77,565.5 x 10,000 4 - 194,415,250 cu. ft. 36. A large number of borings were taken at the site of the proposed dam by the Allied Eng;neers and a generaliza- tion of the foundation conditions enCJuntered is given be- low. The general foundation condition is glacial drift for an unknown depth of at least several hundred feet. The top portion represents an old out—wash plain, through which the river has subsequently cut. This out—wash plain was formed by glacial outflows of varying intensity and velocity, some -times being very sluggish streams because of back water con— ditions; and again at other times being very rapidly flow— ing'streams which did, of course, all the depositing and cutting. When sluggish, the stream seemed to have deposited very fine rock flour, geologically known as mudstone, and locally called mudstone clay beds, being very dense, imper— vious and tough material, which forms excellent foundation and is eroded very slowly by the river flow. These rivers cut through these mudstone layers very slowly so that the erosion can hardly be detected, being as a matter of fact, a cutting of a foot or two over a period of perhaps ten to fifteen years. During the time when the outflow was rapid, sand and grav- el were deposited in layers of considerable thickness, extend- ing below the river valley, and with top at site of dam at elevation 240 feet. Beneath this isscearse sand and gravel heavily water bearing. Above this is a strata of miscellan- eous sand and gravel perhaps 25 feet in average thickness, .through which the river has subsequently cut its present Course. Next above this layer is another layer of mudstone Z57. averaging 15 feet in thickness, and outcropping in the cut banks where the river has entirely worn through it in ages gone by. Next above this is a miscellaneous deposition of sand and gravel which extends clear to the sand hills. Experience has shown that it is entirely safe to build upon these mudstone layers that have been referred to and also that they are sufficiently continuous and impervious to form dependable water cut-offs. The intervening layers have been found to be unstable, and protection against any head of water is afforded by steel sheet piling as shown on detail A. This protection will safely shut off the head in question and as an additional protection, the upstream side of the dam is paved for a distance of 25 feet from the top of the dam to the core wall as shown in detail. 58. CHAPTER V. THE DESIGN OF DAM; CORE WALL AND APPURTENANCES An earth dam was once looked upon by many engineers as merely a fill of earth, and its design was not often considered to be worthy of much consideration, and still more often its construction received little supervision; but today, failures that seemed avoidable have directed attention to it as an engineering structure. It is new gen- erally recognized that the careful attention to details is Just as important in the design of an earth dam as in any other structure. If properly designed and built, it is not only a safe, but also a permanent and natural structure which blends into the side hills and forms a part of the general landscape. it is interesting to note the change in attitude which authors of text books on modern hydro-electric practice have taken with respect to the applicability of the earth dam in large installations. Books published two decades ago devote only a small section to the design and construction of earth dams, while the latest text books available present the sub— ject in some length. A careful study of conditions shows that if attention 18 paid to such features as adequate spillway capacity; con- fining the line of saturation to lie well within the down- 8tream toe; providing correct slopes to both the upstream aInd-downstream faces; caring for drainage to prevent free Passage of water from the upstream to the downstream slepe causing ulitmate failure; and lastly having freeboard such that there is no danger of overtepping from wave action -— then and only then will an earth dam prove permanent. It is with these criteria in mind that the design of the earth dam, included in the next few pages and with de- tails included on accompanying drawings, is carried out. The cross section of the dam is seen to be trapezoid- al in shape which is the natural form ..f an earth bank. A study of the requirements indicated that top width sufficient to carry a paved highway, the design of which is discussed later, would prove to be economical since it fitted in the existing network of roads. The height to which waves will ride up on the embank- ment, although not given to exact determination, may be found by making use of an equation for height of waves as follows. . H = 1.516 - 2.5% where H is the height of the waves, from trough to crest, in feet; and D is equal to the exposure or fetch in miles. Since the actual heights of the waves from mean water is approx- imately one-half that given in the equation by L’: «Stephenson, it seemed reasonable to assume that a top width of 20 feet, paved with an 18 foot pavement would be adequate protection against overtopping. The design of the spillway and its re— lation to freeboard allowance will be discussed later. A slope of l on 4 is chosen for the upstream face run— ning from ground elevation of 240 feet up to elevation of the tOp of the dam, 501 feet, making the total height equal 130 61 feet. The slogge of the upstream face is picked not so ’L-Lo nmch.as a theoretical determination, but is based upon the Inuctical experience of engineers in construction and from their use of structures of this type. This slepe of l on 2 cfi'the doWnstream.face of the danruns from an elevation 280 feet Where a 10 foot gravel road forms the western approach to the power house entrance. This same lepe continuous l on 213>to the tOp of the dam at elevation 501 feet. The sketch below shows the advantage which is gained by placing the core wall upstream from the center of the dam. This is in order to lower the line of saturation, and the portion of the wall extending above the intersection with the upstream face may also be used as a protection to the slope. This removes to a great extent the danger of wash- ing at tkis point which often results in failure due to pip- I/////7 ing. I / / _1_Wafgn.£udhee_ [I COI'C We” L . VStcc/ Sheet Piling Line 915 Safurailo'n The core wall is constructed of 1:2;4 concrete rein- forced with .5 of 1% reinforcing steel, %ufl'bars @ 2" inter- vals near the face of the wall. The core wall is constructed in sections , the first being 25 feet in height and 24 inch- es in thickness; the second section being of the same height but 80 inches in thickness the 2 inch inset on both sides Ibr the placing of forms in the process of construction, and the last section 17 feet in height and 12 inches in thickness. 42. The reinforcement of the top section is further taken care of by allowing the reinforcement of the slab forming the upstream face to extend down and become imbedded in the core wall. This reinforcement is in the form of fabric of electrically welded steel as shown on the detail of the core wall (detail B). The core wall is reinforced in this manner as it is the intention that the two-way reinforcement would provide a sort of a slab action across the areas of unequal pressure and would allow for unequal settlement of the em- bankment and still remain intact. This form of diafragm core wall is of especial importance in this particular dam because of the relatively heavy load on the embankment caused by the pavement and resulting traffic. It was stated in the discussion of foundation conditions that although the mudstone layers were sufficiently contin- uous and impervious to form dependable water cut-offs, the intervening layer, extending perhaps 50 feet below the orig— inal ground level had to be blocked off against any head of water. To form this cut-off, sheet piling is driven to a depth of 50 feet and some distance back into the foot hills as is shown on detail A. The dam in constructed by the method of rolling. Ex- perience has shwon that when the embankment material is spread in thin layers and rolled, the effect of settling is relatively small and extends over a period perhaps of years. The layers are made generally of less than one foot, a thick- ness of six inches being desired in all cases for the mater- ial found in the foot hills from which the embankment mater- ial is obtained. The material is conveyed to and dumped upon n3 C)" o the dam by means of wagons and scrapers are then used to spread the material to a depth of six inches. A watering wagon is uSed to wet each layer subsequent to rolling and the placing of a new layer. A relatively light roller is employed with a pressure of 50 pounds and a penetration of one inch to the wheel. Hand tamping is necessary close to the core wall which is built as the dam progresses. At the core wall the layers of ambankment material were reduced to three inches rather than six inches as otherwise. two percent allowance is allowed for shrinkage in the entire structure. 44. CHAPTER Vl DESIGN OF SPILLWAY AND FLASH—BOARDS In sufficient spillway capacity is the most common cause of failure of earth dams,and one of the failures that caused great loss of life and property, the Johnstown, Pa., flood, was due to this cause.’ A masonry dam can usually withstand overtopping hy water withput serious damage, but should an earth dam over- t0p, the washing away of channels and carrying away of the earth from the tOp and lepes, would be certain to result in its failure. For these reasons much study is given to the spillway design in this develOpment. The spillway 18 not intended to be used except a very small portion of the time, only in case of a break in a dam upstream, and in rare instances to discharge excess water not utilized by the turbines. The advantage of the spillway here designed is that it allows for a pending up of nearly 5 feet additionaflwater over the entire area before discharge takes place. The plan and details of the spillway are given on draw- ing B, but to add to its clarity, a discussion of the con- struction is given at this point. There are a number of flash-boards which are in com- mon use for the purpose of controlling the head water and the type to use on a particular development is dependent on many factors. In this particular type of development, namely, one in which water is very valuable because of the very small pondage capacity available, it is advisable to adOpt a design EAETH Hm cmpzz F; I iLE—Vfl h . PLATE. a. ..l.‘ '. .. .‘.' ‘2 ' ' - g? -6'<--c :xau' Anon NOTE' :EINFOBCE SLAB ALSO WITH 6N0.6 ‘ LEG CTZLC WELD. FABRIC 06 c-c. WALEQE‘IALL- l BEINFOECED CONCEETE Fl ] czo E WALL(5EE Devan.) ___|...L. ., ninja: 3 .. a“; r: .- '.-.. _;.‘.. _ - ' '5 Chew .a 1" . 5» SPILLAW DETAILF9 7 J [— 46. of a spillway which will allow for a minimum of leakage dur- ing periods of drought and still allow an adequate protect- ion. A general description of the flash—boards has already been given in the section entitled "Plant Description", but the semi-permanent device will be referred to in this chap- ter in some detail in order to illustrate the method of oper- ation. The flash-boards are constructed of 5” x 5" x 7’ pieces of cypress wood, such wood being chosen because of its resis- tance to decay from direct contact with the elements. These pieces are bolted together at the top with a support formed by a l" x 2" cross bar of the same material. At a point 2" 7.5" from the bottom end of the panel, the hinge is fastened and this is is turn fastened to a 2” round steel bar which forms the moment arm of the flash-board. In order that the structure be stable and not collapse at uncalled—for times, an additional weight is calculated by the method of moments . to care for this emergency. It is found that pieces of cypress of the same dimension but of length 2’—7.5" will cause a con— dition of stability. This makes the bottom end of the flash- board structure c inches in width. On to this bottom end is fastened a c" x g" x 2" steel angle. This angle is placed at this section to provide a smoother passage of the bottom end of the flash—board structure over the concrete slab of the floor of the spillway, at times when the increase in water level causes it to operate. A recess in the form of a "V" shaped notch is cut out of cypress timber and runs parallel to the center line of the dam. This timber is set in the floor of 47. the spillway at the time the slab is poured. It is in this notch that the angle or shoe of the flash-board sets when the the boards are in their natural position. The fact that the surface of contact between the shoe and the timber is one of the best to minimize the force of friction, aids in the im - mediate functioning of the device when needed, and the weight of the angle aids to cause stability in periods when the lev— el of the water is below that required to operate the flash— boards. The space covered by the individual panels of the spill- Way is 9 feet in length and there are sixteen of these pan- els in the entire length. There are nine flash-boards in each 1 panel and they are placed as shown in the detail on drawing D. The surfaces of contact between the end concrete and the end flash-board are caulked with ashes to prevent leakage, and to further remove this danger, it is specified that the joint be carefully tested during construction, and also that a periodic inspection be made of this detail by the Operators in charge of the station. To illustrate the operation of the flash-board, suppose the water level rises from elevation 294 feet to elevation 299 feet. The weight of the water would be just sufficient to cause the pressure on the upper end of the flash-board to be increased to the extent that this end would begin to lower. Since the entire panel is pivoted, this would cause the low— er end of the structure, the end on which the shoe is fasten- ed to become disengaged from the notch in which it is placed. As the water rushes over the collapsing structure, the angle will slide along therecess provided in the floor of the spill- 48. way, allowing smooth , unobstructed passage of the water over the floor of the spillway. At the completion of the per- iod of flow, or after the level of the water has once more loweredho elevation 294 feet, it is necessary to once more raise the flash-boards by panels, placing the angle back in the notch .The \structure is now ready again for the next advent of high water. This simple structure allows for an adequate protection against overtopping and also is inexpensive and practical since it permits operation without any need for replacement of any parts as is the case in the temporary flash—boards. The construction of the masonry spillway seems to be adequately described by the drawinngn Plate 5. Suffice it to give a short description of the general method of design and construction. The spillway is constructed so that a smooth grade is maintained the entire length of the dam, in order to avoid changes in the grade of the pavement. The bottom of the .spillway channel over which the water passes, is constructed as a reinforced concrete slab, 12” in thickness, resting upon two cross walls which run parallel to the dam. This slab is reinforced with 7/8 inch round bars, placed at 6" inter- Vals, and also with No. 6 Electric Welded Steel Fabric at 6" intervals. The cross walls, on which the floor rests, are Constructed of reinforced concrete, and are l' x 2' in cross section, and run the entire length of the spillway. Their reinforcement consists of the same size fabric and steel bars Which in turn are linked with the reinforcement of the slab forming the upstream face of the dam in one case, and with 55> {O O the floor of the discharge channel on the downstream side of the dam, These details will be clear on inspection of the drawings already referred to. I Running perpendicular to the center line of the dam, and at 10 foot intervals, are transverse walls which are de- signed to support the pavement slab. These walls are design- ed to support traffic loads of considerable magnitude as it is expected that they will serve as an entrance to the power house to be used by trucks heavily laden with equipment. These walls are 12" in thickness and 20 feet in length and 7 feet high. The reinforcement consists of both bars and electric welded steel fabric. This reinforcement is shown on detail D. The discharge channel is formed by a channel slab 8" in thickness formed by 3 concrete slab which is laid on a bed of cinders, one foot in thickness. This bed is to care for the drainage of the channel and possible seepage of the water under the channel floor. The slab is completely re- inforced with No. 2 and 8 electric welded steel fabric spaced 2" and l6"._The sides of the channel are also constructed of reinforced concrete, being walls 7 feet in height, and 8 in— Ches in thickness. The channel narrows from a width of 160 feet at the spillway elevation of 294 feet down to 70 feet at elevation 272 feet. It then runs for 49 feet at the same Width of 70 feet. The sides of the channel slope at a rate or 4 to 7. This feature is designed as being an easy and economical section for the flow of water as determined by experiments with the flow of water in open channels. A cross section of the channel is shown on Plate C. E LE V. 194' r’ I ON ‘ '. —— I~ “if ._ . l y, . E F '1 7 1 IL‘ZE At'L'S‘N‘WmH a” SLAB "‘ .cas-r. ‘ l . I l SCALE ‘ . iii. —-— , *KEINFOECEMENT' no 2 , ELECTRIC WELDED F'At- Z‘xlb" , , SCALE I"-Io' WI,“ I i i I \ \ l 1 I l l Pf ‘ O l C- DOWNSTREAM . SPILLWAV. F57. . b" on No 3-8 ELEC WELD FABRICG C-I J:.. i so :4 ‘0‘ Li" e “.1 5.11 : .trew «: E23, '14 '25. -. . H4 : r-, . r .4 :1 f w." i A ‘ . '5 No.6.ELvWELD. FAD. e SCALE =40 SECTION ALA #— #3»:W“" . " SPILLWAY PLAN 4. DETAIL ”J"! H- up H" n. ”my, 52. Drainage of the channel is cared for by a 6 inch tile embedded in cinders and running from the slope from elevation 501 feet to elevation of the original ground elevation at 240 feet. 1:1 addition, there are provided three installations of 4 inch tiles placed behind cut-off walls, shown in plan and detail on Plate C. 53. | ’L//. e site" a o Loadings: Standard 12% truck load. This load is equivalent to a total load on each traffic lane composed of a uniform load of 575 pounds per limeal.foot and a single concentrated load of 17500 pounds. These loads are in accordance with Specifications issued by the Michigan State Highway Department and are in use by that department in the design of pavement slabs. Moments: (a) due to uniform load of 575#/lin. ft. = 575 x 5 x 5 - 575 x 5 x 5 - 4688 pound ft, (b) due to concentrated loadzof 17500# = 8750 x 5 : 45750 pound feet. Then: Total moment due to both loads a 48440 # ft. Also bd2 = g n . 12; f0 = 1000#; rs. 20000# K Use 2500 pound concrete; p =.OO94 d2 = 48440 x 12 = 59" 5 X 12 X 164 Or d = 7.7 inches or 8". Make the slab 10 inches in thickness to care of pro- tective Coating for reinforcement. And p = .0094 x 12 x 8 = .905 inches in For this reinforcement use g round bars @ 6" c-c. This will give an area of .88 square inches with-the elec- 54. trio fabric in the form of No. 6 electric welded steel fab- ric at 4" horizontal and 16” vertical spacing will give the required area of steel to care for requirements of design. 55. Thgidesign of the spillway channel: The design of the spillway channel shown in detail on Plate C. is here described as a method of design in accor- dance with the principles of retaining wall design for a wall to resist the pressure of earth surcharge. The reference to the formula used may be found in "The Design of Masonry and Foundations", by Williams on page 259. w h2 kO l 2 1 12 110 X(6 X .05 ' no u 110 pounds. (b) Summation of moments around M - 0 110 x 2' 1" = 2 x 8 x 1 x 150 x t' t’ = .095 inches. This thickness is obviously too small and merly indicates that the requirement for moment is not the governing factor in the design. For this reason use an eight inch slab as shown. (0) Investigation for shear along section L M. Allowable shear a 50 pounds per square inch. The average pressure = 6% x 62.5 . 197.5 pounds. 2 56/ Total shear tending to cause shear- considering that the earth back ofthe wall will not support the wall at all thus giving the worst possible condition of design as a factor of safety. Shear . 61 x 62.5 1 g 5 x 6— = 1255 pounds. "T" 3 Unit Shear a V a 1255 s 17 pounds per sq. in. b j d 12 x 778 x 7 (d) Summation of moments around L - zero., also considering no fill as supporting the wall. 8 x 8/12 x l x 150 x 2 s 1600 pound feet. K g M . 1600 . 2.72. Actually K may be 107.4# b 32 I? x 7 X 7 As = p b d a .0094 x 12 x 7 : .7896 sq. in. Reinforce with electric welded steel fabric of such size as to care for this design requirement. No. 4. 57. Qgsign of Spillway slab: a ) } Spillway Slab (Cut-away) I V 51550” 17500 17500 L1 1 // / , .315"“"‘f%en 1 )1 g J 4 X0 7"" w 7'0" v —’( s12" i w l I uz"1k J 1‘ // / I Cross Section LJ/£//I / L_ Loads: End View Uniform load on pavement slab - 575 X 2 X 10 a 7500# Concentrated load on slab - 17500 X 2 - 55000# Load due to weight of wall (AB) 20X7X1X150 - 2100# Weight of 10" slab - 10 X 10 X 150 X 10 - 12500# 12 Then the load per foot . 57100 = 2850 s/ft. “85“ Moment: - l w 12 assuming that the action to be that of 8 a simple beam over the supports to prevent possible crack- ing of the slab. m = 2850 x 20 x 20 = 142500 # ft. “"“‘7?"“““ bd2- h K d2: 142500 x 12 = 870 sq.in. 164- ii d : 29.5 inches. Actually make it 7' 0" thick, the height of the water passage which form 8 the spillway proper. Reinforce with p a 9 X 29.5 X .0094 - 2.5 sq. in. Use 7/83 round bars @ 6" c-c. in two layers 2" apart. 58. The design of the Penstock: Although the size of steel pipe to use for a given discharge varies within wide limits, there generally is one size that will make for the greatest economy of de- sign. The velocity range varies from 8 to 12 feet for heads up to 200 feet. The turbine requirements, indicated by the shape of the load curve, shows a peak load of comparative- ly short duration. In other words this station is to be used for peak load coverage and is intended to serve as a n inter- connected station as has already been explained. This fact influenced the design to a great eXtent because a higher ve- locity is permissable and also more economical. Enger* in an article in the Engineering News Record Volume 70 page 500 derived an equation for the economic diameter of steel pipe lines. This equation follows: ,, J. d = 9.08 e b 0 0° 16 a(R-i) t c3 (l—n)J in which d most economic diameter in inches, e overall efficiency of plant to point of sale, es- timated to be 75% in this problem, b = value of lost energy in mills per kilowatt hour at point of sale, estimated by Burd* to be 7 mills. C = coeff. for use in determining the productive head the value of which is 2.0, Q - average discharge in cubic feet per second, assumed to be 500. D II cost of steel in the pipe in dollars per pound, the value of which is estimated by Gillette to be 0.1¢ t'J 'dward M. Burd, in Michigan Engineer, see reference sheet. 59. R . desired return on money invested (.15%) i - estimated annual operating, tax, and depreciation charges in per cent of construction cost, express- ed as a decimal (.02) t = thickness of pipe ( .575") c a Chezy coefficient ( 110) n p percent overweight due to rivets, overlap, etc., (.2) Substituting these values in the above equation- d = 9.08 .75 X 7 X 2 x 500 X 500 X 500 .l Xul7 x .5 5 x 110 X 110 x 1.2 = 9.08 (5, 060 ’OOO>6 = 109" Use a nine foot penstock pipe of 5/8 inch thickness. The foregoin method, 81tIOUCh being of an approximate nature due to the assumptions made in its solution, is con— sidered to be accurate enough for purposes of design to follew. ' The following stresses taken from the specifications of the Pacific Coast Electric Association are used in the design of the pipe. . Ult. Str. #/sq. in. Tension 55,000 " " . Shear 44,000 " " . Bearing ,95,ooo " " . The details of the design are given here in accordance with the specifications already mentioned. The rivet hole diameter shall be one sixteenth of an inch larger than the shank of the cold rivet. Punching and Beaming: All holes shall be sub-punched and reamed for a butt joint. All holes for lap joint of seven-sixteenths inch or more shallbe sub-punched and reamed. Holes in lap joints pipe of three-eights inch thickness or less may be punched to size. Deductio s for net area: For punched holes, a deduction for hole of three-sixteenths inch greater diameter than the cold rivet shank diameter is made in the computing the net area. For sub-punched and reamed holes, a deduction for hole of one-sixteenth inch greater than the cold rivet shank diam- eter is made in computing the net area. Slope distances: Ldge distances are at least one and a half times the diameter of the hole. Rivet spacing: The distances between the row of rivets is such that the sum of the two net diagonal distances be— tween holes will not be less than 1.25 times the net dis- tance between the holes measured on case lines. (JMU The maximum Spacing of holes alone caulkcd edges is a governed by the formula P = 2% t - d - 1}”. in which t a plate thickness; d - diameter of rivet holes; and p - pitch. All rivets spaces shall be great enough to permit the use of standard rivet dies. Data for Double Hiveted Lap: ##A t : 5/8 inches. d-"4 H 4 j A=1;/- " . 5-1'11 lo ". {real c-51Ao". /F 1 i:. 1 D - 2%7inches . A GBVOCO | a—————+~———Té——— / ‘1’ 1 l—e - A L~ —————— T‘- l l | l 7 6L 0 1 Using the diagram on page 452, Creager and Justin, :hydro—Electric Handbook, for the maximum head on the pipe in feet of water, the following results were obtained. Using a weight of pipe of 470 pounds per feet and a maximum head of 70 feet, a thickness of pipe of 5/8 inches a double lap joint and two plates, the results for the ten- sion are: E : efficiency of joint in decimal, H - loading in feet of water, d = diameter of conduit in feet, T a tension in pounds per lineal foot of conduit on each side of conduit, p - 15000, A = required grossarea of steel per lineal inch of con- duit on each side, Then: Tension per lineal inch = 2.6 H d = 170 x 2.6 x 9 = 5980#. Tension per lineal foot 3 12 X 5980 - 47700#. 62. To remove the possibility of damage to the pipe line which would be caused by collapse should water be removed from the pipe faster than it could be supplied by the fore- bay, an air inlet valve is placed in the pipe line. There are two possibilities for the use of the air in- let valve. If it is desired to empty the pipe line for any reain, the air inlet valve is opened to allow air to enter into the pipe as the contents of the pipe are discharged through the turbine. The second case, one not so important and less likely to occur, is in case of rupture at any point in the line. The type of valve chosen in this design is manufactured by the Barrett Machine Company of Pittsburgh Pennsylvania. The type is the common gate valve and is a standard 24" valve. If.it were not fot the excessive height required where the pipe line is at a considerable distance from the water sur— face, a stand pipe would be used in preference to a valve. This valve is to receive frequent inspection as the pipe line is emptied. The computations for determining the size of the air inlet are given below. Let Q = flow of air through the air inlet in cubic feet per second, 0 - coefficient of discharge through the air inlet, F = area of air inlet in square feet, P - safe difference in pressure between the inside and the outside of the pipe in pounds per square inch, ‘ t = thickness of steel pipe in inches, d - diameter of pipe in inches, 63. s = factor of safety against the collapse of the pipe, Then: a F393 ‘_ 2,460,000 6 t F - 500 5 108 2460000 X .5 .575 F -= 2.6 feet. Use a 24 inch valve. *Engineering News Record, Volume 69, 1914. Page 594. CHAPTER V1 THE DESIGN OF THE POLE?» H LU SE I 1 II I' . ‘ n. jinn I. . w.- IE \;v’ I, m .ILI‘llaqu‘Hd‘ \ - ———_\z ———-——————__< I Fig. ’2 I ’ " 68. The design of a Steel hoof Truss for Power house. The design of a Fink roof truss for the power house 'roof, of span 60 feet and rise 10 feet , and'distance cen- ter to center of trusses 15 feet, is given in detail in the design which follows and in the accompanying drawings E, F, and G. The roof covering consists of corrugated steel sheets supported directly on the purlins. A lining made of felt two layers thick and two layers of tar paper are placed directly upon wire netting that is stretched over the purlins and is required to prevent condensation under the metal roofing and also to act as an insulator. An allowance of 1% pounds per square foot is made for this lining. The snow load varies With the geographic location, with the altitude of the structure and also with the slope of the roof. The value chosen in this design is the maximum value given in specifi- Cation* namely 25 pounds per square foot of horizontal cover- ed surface. As for the load on the truss caused by the wind, the asSumption is made that the maximum value for the velocity 0f the wind is such as to cause a pressure of 50 pounds P9P square foot on a vertical surface. The normal wind press- ure is then on an inclined surface of 180 26', 18.57 pounds per a quare foot . Design pf purlins: The slope of the upper chord is computed as follows: lengtfllof upper chord = 502 - 102 = 51.62 feet. The cosine °f the slope angle equa135%062 : 180 26‘. The panel length fr0m the length of the upper chord is one fourth of 51.62' . - ifdfildinJi : . ...-b...» .1 .55.... are... a... ...... I DEAD LOAD 5T3 V. Hmn LOAD STRESS DIAGRAM. (wmo ream LEFT) F73. I4: F’j‘ I pLATE E, .oOOOOOLQFPOQFj_ T2958 F02 POWER HOUSE. ‘ nnnnnnnn , #265030 @Z:Z5/8 inch. All of the shop rivets are power driven while the field rivets are handpdriven. Joints 2 and 4 : The maximum stress : 4690 pounds. The allowable unit bearing stress for shop rivets, pow- ‘eI‘ ciriven, and in single shear = 24000 pounds per square irlcli, and the bearing value of a 5/? inch rivet on a % inch plate - 5/8 x 1/4 ;-: 24000 _-_ 5750 pounds. The rivets through nusnflaers 2-6 and 4-8 are in single shear, and with an allow— atiLe unit shearing stress of 15500 pounds, the single shear ‘vaJJJe of one rivet is .5068 x 15500 = 4140 pounds. This val- 1ie, being greater than that d termined by bearing will gov— ePII. Thus, at the end of the members 2—6 and 4-8 , 4690 — l 4140 rivet. Use two rivets. Since the upper chord is pushed against the gusset plate Witll a force equal to 650 pounds, there must be sufficient PiVErts in the chord member to withstand the pressure. The riVetm are in double shear and bearing on a % inch plate. The lattfler condition governs, the allowable value of one rivet is ‘4690 pounds and 2502 = 2 rivets are required. In the de— 4690 tail_ 5 rivets are used so as to place the end rivets in the ba£fli gage lines of the angles and thus secure a more rigid and_ Symmetrical arrangement. The size of the gusset plate is Slicwn on the detail as is the spacing of the rivets. Joint 5: hembers 5-6 and 5—8. Laximum stress = 7425 pounds. The bearing value of one rivet on a L inch plate = 4699 #. The number of rivets required = 7425 = 2 rivets. 4690 s N: .0_M z “.4 Ha .I .1 I. b 2 ...um "M1300 J. 1 .. .....tx..%x..«n_u..._l .. \ + ”w M. .3. _ . \. \T\\\ Ifll ldleIN QM 6 Us“ \\ LI\\\ “ I H . \‘H\\ ifluwr mu *—— \\ Ir \ .- \\+\V‘\\ — .- ‘ \I :~. m to I— v. .— . .4: :1: 11. (was ruit av? . 9: ..wf..int 7 part of the stresses in the lower chord members will IDEB transferred across the joint through a % inch splice plate Illlder the lower chord. Tfe rivets in the splice plate through Iniemmer 7-7' are shop rivets and those through member 6-7, are If'flLeld rivets. Six field rivets will be placed in the splice plate on 1Slne left side of the joint, and 4 shop rivets 0n the right Eiide. The strength of the plate : 4 x 5750 : 15000 pounds. The amount of stress still to be provided for from the member 6-7 is 58570 - 15000 = 25000 pounds. The rivets 1 u, 1~_l“1V"V'rO.' J ,4‘. 3:91)! 5‘: v _ =A , . n: \' ...??? Ja (17w / .. I¥NKM “N um?! Jn \\ @211. 98.“ through 6—7 and the vertical gusset plate are shop rivets, which bear on a 5/8 inch plate = 7050 pounds. Therefore the number required = 25000 = 4 rivets. ' 7050 Member 7-7‘: The amount of stress which must be transmitted from man- ber 7-7' by the rivets in the gusset plate = 25760-15000. The value of one rivet (hand-driven in bearing on 5/8 inch plate) is equal to 4690 pounds. The number required then .-.- 8670 : 2 rivets. 4690 Design o_f_ 9nd j_0_i_11t_ and bearing; The 5/8 inch plate at the end g'oint is extended below the lower chord member to permit riveting of a pair of shoe angles to it, the purpose of which being to transfer the end I‘ezaction to the gusset plate. A sole plate is riveted to the bottom of the outstanding legs of the shoe'angles to stiffen this portion of the angles. The sole plate is allowed to rest 011 _a bed plate which is anchored to the masonry. The number of rivets required to take care of the com- Pbessive stress in member 1-2 . 493339 = 7. Make the number 9 to care for bending stress cause by the loads on the in- termediate purlins. The number of rivets required in the lower chord member ec1‘L1als 45870 = 7 rivets. This is member 1-6. A 1:222? of £7299 = 5 rivets is required between the shoe a«bl-glee and the gigggt plate in order to transfer the result- ant end reaction to the plate. The shoe angles will be made 3 .x 5 x 5/8 inch by 10 inch. The area of the bed plate is determined by the maximum ..m wuboflp 0:... a nun wv norm N ..m : x m x o. mh<4n 0mm ..m: ..w ..o. ”:30. mac» antic. mien z; «N... undo: 3.»...an [is lOO. vertical component of the end reaction. Assuming an allow- able pressure on the masonry wall of 500 pounds per square inch, the area required ;.- 16900 = 56.5 square inches. The 500 width of the piate parallel to the span of the truss is made 6(1112311 to the length of the shoe angle, 10 inches. The lengt h °f the plate parallel to the wall must be made sufficient to DbOVide for % inch anchor bolts outside the shoe angles. A length of 6 5/8 - 2 x 2%.— : 11 5/8 inches. The bearing thus provided a 10 x 11 5/8 : 115.7 square inches, which is some greater than is necessary. The thickness of the sole plate a nd of the bed plate is determined by treating the portion projecting beyond the Shoe angle as a simple cantilever with an upward load equal to the maximum allowable pressure on the wall, 500 pounds Per square inch. For a 1 inch strip of plate 3." _l x 18000 x 1 x t'2 equals'SOOO t2. Solving this equation for t theevalue is .56 incthes. Use a 5/8 inch plate. [For .5/4 inch anchor bolts passing through the slotted holes in the sole plate—to allow for the movement of the truss dull? to temperature change and deflection, an allowance of 1 inch per 100 feet of span is ample allowance to make for this. The length of the slotted hole is made equal to the diameter or the anchoe bolt plus twice the expansion. Or L a 2 3: .6 plus % inches : 1.95 inches. Use 2 inches. The diameter of this hole is 5/4 inch plus 1/4 inch or one inch. Ordinarily the center of the sole plate would be placed on a vertical line through the intersection of the gage lines or members 1—2 and 1-6. Since, however, a large bending mom- _ent is caused by the intermediate purlins in panel 1-2, the 101. shoe villube placed to the right a distance equal to the moment at the end of the member 1-2 divided by the maximum Vertical component of the reaction, 2193—69 s 2 inches. 16900 Miscellaneoug Details: Each intermediate purlin is riveted to the upper chord as shown in the figure. The end purlin is fastened to an ex— tension of the gusset plate at the end joint by means of a atandard connection, as shown in the detail drawing. On acc- ount of the arrangement of the truss members at the end joint there is not enough strength in the upper chord to properly support the purlin at this point. Two angles 6 x 4 x 5/8 in. are used for the connecting angles, the length of which are 3 inches. The 6 inch leg is placed along the web of the I— bean and the 4 inch leg along the gusset plate. All the members which are composed of two angles are I'Z’LVreted at frequebt intervals in order to distribute the Stress equally between the two members. In the present case Since the angles. are separated by gusset plates, a washer is Placed between them at each rivet in order to maintain equal distance between the angles. The rivets which are used for this purpose are of the same diameter as the rivets used at the joints. These rivets are shown on the drawing of the ass- e1111:):Led roof truss which accompanies this explanation. 102. Design 2: Power House Floors: flmtion 2. Operating floor (see figure 51) Floor Plan. The design of the slab shown in Figure 52 is as follows: Loads carried by the slab: Live load due to people ------- 100 lbs. per sq- ft. Dead load due to concrete ----- 50 lbs. per sq. ft. Additional load as factor of safety against accidental loads -—" 50 lbs. per sq. ft. TOTAL '200 lbs. per sq. ft. Take a section along A B C D (section 1—1) on Figure 51, €u16. llsing a 2000 lb. concrete for which fc : 800 pounds per Sqllzare inch; fS equals 16000 pounds per square inch; n - l5; axui_ making use of the diagram on Page 540, Hool's "Reinforced <30:1<3rete Design n, K : 147; p = .0108, Then M e K b d2 M a w 12 . K b d2 l 2 200 x 10 x 10 x 12 . 147 x 12 x d 10 d2 : 15.69 square inches d a 5.7 inches. Use a 6 inch slab. Sincethe minimum thickness for a slab in such a loca- ti-C>:n and supporting such indeterminate loads, is around one hExJ_r a foot, it seems desirable to take this value, and the :fEHBtor of safety added is assumed to be welcome since there i§3 always a possibility that construction loads may accident- a1Sly be placedaon the slab over an unsupported region. This is! of especial significance in the design of the operating floor. Egg? 1 ! l — H.002 PLAN o_F oceans Quill may n. massage: 104. As = p b d - .0108 x 5.7 x 12 u .48 square inches required. For this steel requirement, 5" square steel bars 0 6" space, are used. This steel furnishes an area of .5 sq. inches which is sufficient. Reinforcement is also placei in the opposite direction to the main reinforcement as shown in the detail of the slab, to tame careof temperature stresses and also to bal- ance the reinforcement in the slab proper. Investigation for shear: v = V : 200 x 5 = 26.5 lbs. per sq. in. 5'3_d IE‘TTTTEWVEETFFT There fore no diagonal reinforcement is necessary. Investigation for bond: The maximum bond stress occurs at the supports in the reinforcement for negative moment. At the supports the unit bond stress is u 2. V = 200 x 5 = 79 lbs. per sq. in. :0 J E 4 x .857 x 5.7 Design of slab at Section 2—2 (see figure 55). Using a 2000 pound concrete; fc- 800; fS = 16000; n - 15; K a 147; p - .0108 as before. Then, 1'1:le =Kbd2 200 x 10 x 10 x 12 - 147 x 12 x d2 10 d a 5.7 inches. Use a 6 inch slab as in the previous design with identical reinforcement. The design of the slab at the sections (a) and (c) as well as at section (b) is the same as the design of the slab at section 1-1. A six inch slab is used throughout the power house operating floor and the details of the reinforcement Will be seen by an examination of the detail drawings which have been letterei to correspond with the description here giveri. n. 1..-] 105.. Design of Cross Beams. ( A -1 ) ( 1-4 ) etc. Loads on A-l 2 10 x 150 = 750 # due to concrete slab. 2 1000 # due to live load of people. Total I750? per foot of beam. Loads on 1—4 = 5 x 150 = 575 # due to concrete slab. 2 500 # due to live load of people. Total 875 # uniform load per ft. of beam. Concentrated load on 1-4, = 9.45 X 25 - 255.75 # at third points. Additional weight of beam . 61.75 # per foot of beam. Also add 2500# load due to live load of people. Total 2800 # concentrated at the third points. Insert: Design of I-beam to support grating. Load on I = 50 x 9.45 = 471.5 # due to grating. 50 x 100 .5000.0 # due to people. Total 5471.5 # per foot. Moment = 11_2 = 547.5 x 10 x 10 x 12 = 82,072 #". From diagram use 5" I-begm , weight 12.25 # per foot. The weight on this I-beam - 12.252x 10 B 61.75 #. :106. Design 23 beams. (con't.) Referring to figure55 in this set of detail drawings, the following design is of the beams numbered A-l, 1-4. The bending moment at the center of the fifteen foot span is, as in preceding design considered to be M : l W 12. 10 M = % x 1750 x 15 x 15 x 12 = 475,000 pound inches. 0 Considering an end view of the slab under consideration as given in the sketch below, and using the following values f0 = 800; fs : 16000; n : l5; ' =.857; k a .429, 48" ’1 6" WEQ'f-il-‘fl ':' T— M = fc(l- t )botojodo C 2Ed M . 800 ( l - 6 ) 48 x 6 X .857d = 475,000 0 2E .429d from which d = 9.4 inches. MS. fs As 3 d. 475,000 = 16000 x .0108 x 48 x d x 857 d from which d2: 66.4" d = 8.15 inches. A check will be made of these values by the use of the diagranx on page 524 of Hocls "Reinforced Concrete Construction" Vol. 1. p = .0108; n = 15; fs - l6000#/ sq. inch. ; f0: 800#/ sq. inch; 3 = .45; k : .45; j : .857; maximum fiber stress in steel. corresgonding to fc equal to 800 #/ sq. inch = 15900; maxi- mum fiber stress in concrete corresponding to an fS - l6000#/sq. inch is equal to 805. 107. Then: M r = 14705 5 32 M s 475 000 : 147.5 48 d2 from which d : 8.15 inches. Add 1.85 inches to make the total depth equal to 10 inches. The protective coating makes the depth as shown on the detail drawing of 12 inches. AS=Pbdo .0108 - AS = 5.184 inches. 48 x 10 For this steel requirement use 8 seven-eighths inch bars at 11" center to center in two rows as shown in the re— _...-4.... ..“-. _’ inforcement sketch. Design of beam number 1-4. Consider the moment in the center of the slab as shown on the drawing of“the location of this beam (Fig.5) to be as before; M - W 12 10 M = 875 x 15 X 15 x 12 =.256,25O inch pounds. b? = 18"; fs = 16000# / sq. in.; f0 = 800 # / sq. inch; n z 15; p = .0107; k = .429; j = .857 Me = 256,000 a 800 ( l- 6 ) 18 X 6 X 1857d X .429d from which d = 11 inches. Make 12 inches to correspond with the ad- jacent slab just designed. I p ; .0107 = A8 EE—E—11 As . 2.118 sq. inch. 108.‘ To care for this steel requirement, reinforce with four threeéquarter inch bars in a single row suaced one inch between surfaces.(see diagram below) I Design 2; beam numbered 8-0 (see fig. 1) The load on beam 8-C'is composed of live and dead loads. The live load is composed of 15 X 10 X 100 - l5000# due to the weight probable by the load of 100# per sq. foot due to people. The dead load due to concrete is!: 15x5) + (5X10)]x 150 pounds equals 9575# due to the weight of the gonerete. The weight of thegrating = 25 X 9.45 - 237.75 #. From the above computations thetotal load on the slab 8-C‘: 24610.75# and this is equal to a load per foot of 1640#. M = 1640 X 15 X 15 X 12 = 442, 800 pound inches. For n a 15; 7: - 16000; fC ; 800; p s .0108; j - .857 and k . .45, and a value forfiggn 147.5 from thetable on page 524 of H001 Volume 1 already referred to in preceding design, d2 = 442 800 . 62.2" d —. 7.8 inches. Make the beam 12 inches. As = p b d = .0108 X 48 X 8 = 4.1472 square inches. For this steel requirement use 8 three-quartrn inch bars r 1:090 ° \ spaced at interval of one inch edge distance as shown in the following sketch of the location of reinforcement. Design of beam numbered 5—6 (see Fig. 1) The loads on the beam under consideration are composed of the following: Load due to concrete - 15 X 5 X 150 - 5625 #. Also 150 X 5 X 5 - 1875 #. Load due to grating - 50 X 9.45 = 471.5 #. Load due to live load- 150 X 100 - 1500.6 #. 22971.5 # This load is equivalent to a load of 1550 # per foot of beam. M a 1550 X 15 X 15 X 12 1 415,000 # inches. 10 - Mr ——- . 147.5 1x12 From which d = 7.6 " = 8 inches. Use the same section as in beam 8-C‘. 7 110.“ Design g£_Cross Beams gn Operating Floor (see Figure 53) Design of beam (GE-X) M 3 12(5075 X 15- 80 X 15 X %? - 1875 X 5) - 555,000# in. bd2. M PfsJ . 555 000 . X X . = 2260 square-inches. 7 Assume b = 12", d2 a 188 from which d . 13.7" . 14" Add 2" for protective coating making thetotal depth - l6inches. As = 12 x 14 x .0107 . 1.8". For the above steel requirement us 8 4 three-quarter inch bars placed at 1%" edge distance. A - 4 X .441 - 1.764 square inches. The bond for one bar at the left end ofthe beam - U. = iii-V". = 5075 = 10805 # O. K. 20 3 d 2.556 X .857 X14 For plain bars thenumber that must be extended straight to the left end of the beam is 108.5 a 1.55 a 2 bars. Bend up two bars as a result of the igove computations. v - V . 5075 a 21.4 # per squareinch. 0. K. bja 12 X414 X .857 Investigation for bond and shear. V = V 8 1750 X 705 2 10065 iii/sq. in. A-A bjd .857 x 12‘x 10 x 12 i v = V - (875 x 7.5) + 2800 = 7.6 #/sq. in. i 3'5 BEET’“‘“‘ .857 x 12 x 12 x*10 ulo zolFumm mlmlomo - “a m mDOI NMZOQ 1‘ “84“ MANP‘UMZWG .NPNJU «not 33 xmrr 020.2 moon... ozzkmmno umber. umgoa .5 29.5.3 whose -mlmrlu N Ice...— ugeu meme "0.6 a win Hues .< < oxeni Mocha 92.8.3.on unset mulch LO 29...wa mmOuu a 4%... .2d.> “—3... 10 22020 5:02 FININU‘OIZ.H‘ .. NPOZ . as mi wens .05. 47777... 020.? mean... alkzumno wane: mazes LO 20:.an ““ch Emil 3.0.... mug 5sz.: N<.:t.n 44¢ r: ZOEbDurrmzs 4(quon .520 #1. ...uzrm 2. 22.020 {(MO .H .3w.> 9:? 20 23010 ....02 ...zutmuuouzfiu ”who: F 5* _115. DESIGN 9: AUXILIARY FLOOR A B. (see elevation drawing) Fig. 57 The auxiliary floor,designed merely as a support for workers employed in the inspection of the turbines and other repair work, is not designed to carry excessive loads as have the floors in the preceding designs. Loads on the auxiliary floor - 100# due to live load. 50# due to concrete. For this design consider a section along AA'B'B. Using a 2000# concrete for which f0 = 800; fS - 16000; n = 15; and the diagram on page 540 H001 Volume 1, K 147; p s .0108 M a K bdg M a 12 = K bdz. ‘10—— 200 x 10 x 10 x 12 = 147 x 12 x d2 10 d a 5.7" Use a 6 inch beam. As . pbd - .0108 x 5.7 x 12 = .48 sq. inches. For this steel requirement use %” square bars at 6" c-c. To prevent temperature changes from causing cracks and also to bind the entire structure together, 8 4" bars will be placed transversly in each 15 foot panel. The unit shearing stress a v - V - 200 X 10 35357"' 5.75x .857 X 12X 2 equals 26.5 #/seuare inch. No diagonal reinforcement is nec— essary therefore. The maximum bond stress occurs at the supports in the reinforcement for negative moment. At the supports theunit bond stress : u = V7 8 200 X 10 X 6 i 79#/ sqo in. 00K. {63d"' 2(1857 x 5.7 x712 x‘2) or. wxm’mh‘wv » 4 , » - , m.‘ , - 1 , n”, .. imam-mouse; m 31% '7. m 7 , ; _____ ' , -a=AM 5 7225* ‘iwxmwzv' FLOOR PLAN File. 3__'}_' 117. The section across the grating is designed similar to the slew already designed and is made the same size as the floor just designed. I—IL... Il‘la. Design 3: Exterior Columns. In ordinary column design, the loads are assumed to be concentric and applied at the longitudinal center of gravity axis of the column. Even in such a design, the assumption is necessary though the condition be theoret- ' ical only. However, when the load is considerably eccen- tric such as may occur in spandrel framing or as in this design, by beams carrying crane brackets, a column invol- ved has to be carefully investigated for the combined stresse es which result. Such a column must resist the sum of the direct and eccentric loads as well as the bending induced by the eccentric load. If P = the direct load; R n the eccentric load; e - the eccentricity, or the distance of the point of applica- tion of R from the axis of the column-- then the direct stress equals Direct stress : gLi_R , in which A equals the cross sectional area of the célumn. The bending moment - M1 : R e. The stress due to this moment - M c . T The value of s is compression on the bracket side and tension on the exterior face. The maximum compression = P + R 4 M c A I = P e R + R e c _1_—1"— The loads are an follows: Total dead panel load . 150054 x 8 - 10400 #. Total wind panel load : 2200 #,x 8 : 22400 #/ Total snow panel load 4 2800 #. X 8 = 8800 #- 117b The Total load is therefore: 41,600 pounds. One half of the dead plus snow plus wind or P . 20800#. the total weight supported on theexterioe columns. The load R is equal to the crane reaction which is emueal to 72900 pounds. See page 411, Barrows, Water Power Eng ine er ing. The distance "8" or thabeoentricity equals 15 inches. The length ofthe column is equal to 20 feet. The section assumed consists of : Web plate 12 X E" A - 56.76 sq. in. 4 angles 6 x 4 x 2" IH . 885"4; r4 - 4.91" ' 4 I” . 266" ; r_ : 2.69" The total load is equal to 20800 + 72900 - 95700#. P (direct) a 95700 = 2550 pounds. 33‘73“ . O P (indirect) - 72900 X 15 x 6.25 c 7710#. 885“» The total stress, both direct and indirect . 2550 + 7710 . 10620 Pounds, the actual stress. The allowable stress - 19000 - 100 X 20 X 12 a 10750#. 2.69 The assumed section is alright. The details ofthe column base, bracket and the column itself are shown on Sheet H, page ll7c. 45 644 . are ‘E -g'. COLUMN BASE ‘u. n - I \\\\\\\\\\\\\\\\\\\\\\\V \V \\ -\\\\\\\\\\\\\\\" —f a u .r COLUMN DETAILS 26 ... fi I—H. L~l «MW- ..m.‘ 0 1“ 7 . , , \1\1..)/-\\NH\W‘./7\1\\w2.~vl)l\ll-m u. 1 M r1— Lind The design of the Column Base: The base forthe column designed in the previous pages is a built-up base on concrete. The loads on the column base equal 5000#. the weight of the column, in addition to the loads previouslu calculated. The allowable pressure of the column on the concrete equals 500 pounds per square inch. The required area - 97000 a 194 square inches. For this area try a base plate 20 inches square. The actual area of pressure a 97000 - 245 square in. Try a 6 X 4 inch shoe angles - 2 1 1 M I E b I: 243 X 52 X 5? I 2,140 7’". t 6 x 2140 a .895 " required. L "IEUUfi‘ SSEEy % + E u 1.25 inches which is in excess of that required, but is used to give sufficient bearing to the steel column and still allow room for fastening the angles to the base. Use 6 x 4 X 5" shoe angles and a 20 X 20 X %" plate. Test the plate between the column flanges. M = e . c2 . 245 x 112 z 2450 #". I2 __—12_—‘ The load outsidethe column face a 5% X 20 X 2.45 . I = 18,220#. 22, I C7771 1n each angle. Rivet the base as shown in the figure on Page . Single shear rivets, £", - 5500#. There are 4 gauge lines available 118. Design 2: Counterforted Retaining nail: In the design of the ccunterforted wall as shown in the accompanying pages, the application of the pressure of the earth fill which forms a part of the earth dam, is made by a study of the earth pressure theories of Good- rich in the Transactions of the American Society of Civil Engineers, Volume 55, page 501. Let P . the resultant earth pressure on a vertical surface for a length of wall equal to one foot. h . total height of wall in feet. w - equivalent liquid pressure. 5 - the angle of internal friction of the earth r111 assumed to be 57°. 0 = the angle of inclination of the earth fill, equal to 260 40' as shown on the sketch. 2 -r—r-j—T 7e24— In this equation the negative sign in the denomina- tor and the positive sign in the numerator give a value for the passive pressure. A reversal of the signs gives the value of the active pressure. The active pressure is the pressure used in the design,of the wall. The load P acts at the third point of the height of the wall or 7 feet, ans is assumed to act at the same in- clination as the earth fill of the dam. P, the active pressure - 19700 1.89565 - .4 - 7500# O acting on a vertical surface. This is equivalent to a force of 6700# as the force PH. 119. The stability of the counterforted wall as regards overturning may be determined in either of two ways, name- 1y: (1) By use of a theoretical formula for the thrust of the earth; or (2) By making the stability against rotation equal to that of a gravity wall that is known to be safe. In this connection, attention is directed to the presence of a load of considerable magnitude, shown on thedrawing of the pressure distribution and labeled L. This force, which is the application of the roof loads and that por- tion of the floor loads which finds its way to the foun- dation, acts as a direct column load and tends to aid in preventing rotation. This force also tends to aid in causing a stable condition of the retaining wall. This load is considered to be composed of the entire roof load acting on the exterior column, and will be considered to be applied at the juncture of the counterfort with the mainwall. The effect of sliding will not be considered due to the fact that the base of the wall, B C, on the drawing, is constructed monolithically with the floor of the power house. The bearing power of the soil in short tons per sq. foot in this design is taken as 5 T. per square foot, and is considered to be a force at the toe of the base. The type of wall selected in this design is a counter- forted wall which was chosen for two reasons, (1) because it permits of the strongest pretection against the reaction 120; due to the fill of the earth being rolled and possible settle- ment of the earth dam, and (2) because the wall demands strengthening at the points of application of the superstruc- ture loads; also an increase in size to permit fastening the shoe angle of the exterior column. The principles recommended by the Joint Committee Report for the design of retaining walls are practically as follows? (1) The unsupported toe and heel of the base slabs shall be considered as cantilever beams fixed at the edge of the support. (Conditions somewhat different in this particular case because of the monolithic construction of toe already mentioned.) (2) The vertical wall of the cantilever shall be consid- ered as a cantilever beam fixed at the top of the base. ~(5) The vertical sections of counterforted walls and parts of base slabs supported by the counterforts shall be designed in accordance with the requirements for a contin— uous slab built to act integrally with restraining supports and assumed to carry uniformly distributed loads. (4) Counterforts shall be designed in accordance with the requirements for T-beams in regard to flexure formulas and flange width. Stirrups shall be provided in the counter- fort to take the reaction when the tension reinforcement of the base walls and heels of bases is designed to span between the counterforts. Stirrups shall be anchored as near the ex- posed face of the longitudinal wall and as close to the low- er face as the requirements for protection covering permit. (5) The shearing stress at the junction of the base with the counterforts shall not exceed the values specified for diagonal tension and shear in beams. 121: (6) Horizontal metal reinforcement shall be of such form and so distributed as to develpp the required bond. To pre- vent temperature and shrinkage cracks in an exposed surface, not less than 0.25 square inches of horizontal metal rein- forcement per foot of height shall be provided. (7) Grooved lock joints shall be placed not over 60 feet apart to care for temperature changes. (8) The walls shall be cast as a unit between expansion joints, unless construction joints formed in accordance with the Joint Committee requirements are provided. (9) Drains or "weep holes" not less than 4 inches in di- ameter and not more than 10 feet apart shall be provided. At leats dne drain hole shall be provided in each pocket formed by a counterfort. (10) The protective covering for the concrete in contact with the earth shall be 5 inches; that exposed to the weather shall be 2 inches. DESIGN: In this design the vertical slab is supported at inter- vals of 15 feet by vertical ribs or counterforts. These coun- terforts act as cantilevers and are securely tied to both the vertical wall and the footing. The projecting toe of the foot ing is a cantilever while the inner portion is a slab support ed by the counterforts. ‘ P’orL. jfliignfi} (l) B D is composed of narrow :? 7 strips uniformly loaded with the g b dead weight of the slab, the down- F73-. i 7 ward weight of the earth, and the iéEL' upward reaction of the soil. 7". l D 1‘ '61 11.“; 5' 3:335? 35;. c, 122. (2) B C is considered as part of the floor system as already explained. (5) The curtain wall is considered as made up of a series of horizontal strips and treated as slabs partly continuous and uniformly loaded. The pressure against this wall changes as the height of the wall so that the pressure upon different strips increases with the depth. (4) The load on the counterforts is made up of that portion which is transmitted from the curtain wall, which takes the pressure. This value is obviously very small. The thickness of the counterforts is made sufficient to insure rigidity and give the necessary space for the rein- forcing rods. DESIGN Qg inn nnnn. Referring to Pagein, Figure (a) the height of the wall is seen to be 21' O". The counterforts are spaced at 15 feet center to center. The angle of inclination of ' the earth fill, equal to the angle formed by a 2:1 slope, is 26° 40'. The equivalent liquid pressure is assumed to be 25 pounds. The allowable pressure on the soil at the ’ toe of thebase is assumed to be 6000 pounds per square foot. The coefficient of friction between the subgrade and the concrete base is assumed to be .4. fS is equal to 16000 pounds per square inch; fo = 650 pounds per square . inch; "u" for deformed bars equals 100 pounds per square inch; for plain bars, "u" equals 80 pounds per square inch; The unit shear taken by the concrete equals 40 pounds per square inch. Assume % - .7 and investigate the toe unit pressure 79:41; . g! fi,’-‘i§ an— ‘ 4...: 7;: ..:; _1 _ 15 iflfl Infra Harm—D wanna who. ’ 124. and resistance to sliding. From Figure 29, H001 and Kinne, "Reinforced Concrete and Masonry Structures”, when the ratio % = .7, n . .475, or b- .475 (21) - 10 feet, and X - .7 X 10 - 770". The unit pressure at the toe - *p : 6O ( h + 5h x + x3 ) ‘5.8‘b = 4266 pounds per square foot. This value is less than is allowable so is 0. K. For the purpose of investigating the resistance to sliding, it is assumed that the thickness of the vertical wall is .l of the total width of the base. The thickness of the base may be assumed to be equal to the same pro- portion of the total height of the wall, namely, .1 X 21‘. The difference between the weight of a counterfort and an equivalent volume of earth is so small it is neglected. w =( 0.1 (21( 10 + (.9) 21(.1) 10) 150 + ( .9 (21) 7 . ( ) ( 5.5 (7) ) 100. ’2— ) W a 20,440 pounds plus the load L - 20440 + 5000 . a 25440 pounds. PH: w'2h2 = 25 £22)2 . 6050 pounds. Since PH is less than .4 W, this base width and posi— tion of the vertical wall is satisfactory. These dimensions are: Base width = 10 feet; therefore thickness of vertical wall is 1 foot. The height of the vertical wall - 21 feet; therefore the thickness of the base is made 2'6". The rear portion of the base slab is designed first as in the case of the cantilever wall. To get the downward pressure on this slab, assume that the thickness of the base slab g .l the height of the vertical wall as before. 125. Then the downward pressure at C 3 .9 (21) 100 - .1 (21) 150 a 2200 pounds per square foot. The upward pressure at C - .7 (4266) = 2985 pounds per square foot. The downward press- ure at C = 2200# and the upward pressure a 2985, then the resultant upward pressure at C c 2985-2200 a 785 pounds per 'square foot. The downward pressure at D a 2200 - 5.5 X 100 - “2550 pounds per Square foot. Since the upward pressure at this point equals zero, then this value is the resultant downward pressure at this point. See the Pressure distri- bution diagram (a). ‘ . * The portion of the slab C D subjected to the great- est bending moment is a strip one foot in width adjacent to point D. If it is assumed that the slab is continuous 'under the counterforts, and that therefore a moment coeff- icient of i may be used, then the moment : 12 M s 1 w 12 = (2082 + 2550) (5.5)”. 70,050 # n. f 12 2 From the formula M . K b d2, 0. .1 M = 70060 . 7.57". K'b' (107 x 12 The shear V = w l s 2082 r 2550 X 8 - 9264 pounds. For 2 2 X’2 shear the value of d . V - 9264 a 26.4 inches. 5 j v 12 X .865 x 457“' A slab thickness of 2' 6" will be satisfactory. Substitut- ing in the formula A c 70060 -.189 sq. in. S 15000 x :865 x 26.4 Since the pressure at E is zero, the area of steel required at this point is zero, while at a point midway between E and D it is half of that required at D or .095 square inch- ? es. S0 for the 2 % feet of slab adjacent to D, a" round bars @ 6" c-c will be used, and in the remainder of the 1 slab, a" round bars @ 12" c-c will be used. This is more I‘ll‘lll‘uilllul I . n. \ I A4 g(I55) / \ I l / ifimw/ \ b 2 186) // \ +( \ / \ I ms z:___q (C) 2'6” tac_7___ __ __ _- \ \ \ 9% b= I ’ " ,’//’ 3) e1 .04 Oji/ '1 fl ml N ,,/’ VtI 4,,»J’/’ (a) P725550 2; D Isrn IBUTION Dmc 72AM~ 127. steel than the design required but is put in to bind the base together. The bond stress in the bars near D s u = V b : 40 X 6 . 155 pounds per square foot. This ‘1:57“ value is slightly more than allowable butis used since twice as much steel is used as is necessary. Since the slab C D is 2.5 feet thick, the clear . height of the wall : 21 - 2.5 = 18.5 feet. The height of the earth fill acting on thevertical wall - 18.5 + 5.5 - 22 feet. There fore the pressure at the base of the wall is 22 x 25 = 550 pounds per square foot. Since thevertical Wall is continuous across counterforts M = ;_w 12x 12 = 550 x(5.5)2 . 16620 inch pounds. The depth requirel for moment = D =4, M a 16620 = 5.6 Inches. K B 107 X 12 The shear V = w l a 550 X 5.5 . 1512 pounds. 2 The depth required for shear a d - V - 1512 5 j v 12 X .865 X 40 equals 56 inches. Use a thickness of 12 Inches with an effective depth of 10% inches. The area of steel required at the base of the wall a As = NI I 16620 I 0115 sq. in. j d 16000x .865 X 105 Use %” fgound bars at 6" c- c. T is also is more steel than is needed. Place this steel 2" form the surface. u - V b Z equals 40 x 6 = 122 pounds per square inch. Use 4 @ 6"; 9 @ 8"; 12 @ 1' 0". See Figure (a). The length of the toe A B is 10' - (7 + l) . 2'0". The moment at B s 5410 (2)2 + (4266+5410) 22 . 7960 #1. 2 3 The depth required for moment = d a 17960 X 12 - 8.6 ". 107 x 12 128. The shear at B - (4266 + 5410).2 : 7676 pounds. The 2 depth required for shear a d = V = 7676 . 20" b j v 12 X .865 x 40 The toe will be made 20” thick from B to A. The area of steel required is A = 7960 X 12 u .542 sq. in. S 16000.2‘1865 x 20 Use %" round bars @ 5.72 c-c. Then the bond stress - u = V = 7676 g 155 pounds per sq. in. ojd 12 X .865 X 1.57 X 20 - BT72 This value is more than allowable. The area provided by a" round bars @ 5" c—c is .47 square inches. Then the bond is 115 pounds which is still too large. The area pro- vided by 5" round bars at 4%" 0-0 = .522 sq. inches. The bend provided by this steel is 105 pounds per square inch which is 0. K. The horizontal steel in the counterfort must be so designed as to be ableto withstand the horizontal pressure against thevertical wall. As given in the design of the verticall wall, the horizontal pressure on the lowest 1' strip of vertical wall is 550 pounds per square foot. Since the spacing of the counterforts is 15' c—c, the total force is 15 (550) = 8250 pounds. The area of steel required = 8250 - .515 square inches. This area may be 16 00 provided by 5" square bars @ 7" c-c. The center of the strip 1' wide where the pressure is 550 pounds per square foot is 18' O". The area pro- vided by 4" round bars @ 12" c-c is .20 square inches. This spacing may be started ata point ( .2 ) 18 - 15' be- 275_' low the t0p of the vertical wall. Since this spacing of rod; is practically the same as the spacing of the hori~ zontal rods in the front vertical slab, the same spacing 129. will be ad0pted for both. The total downward force to be resisted in the out- ermost section of the counterfort - l5 ( 2082 - 2550) = 2 54740 pounds. To carry this, an area of steel of 54740 or 2.17 square inches must be provided. This area can be furnished by 5 3" bars 0 6" c—c. This spacing is also adep- ted for 4' of the counterfort adjacent to D and will be in- creased to 12” c-c. for the next 4 feet. From E to C no vertical rods are needed since the resultant pressure is upward. Both the horizontal and vertical rods in the counter- fort are hook d around the horizontal bars in the vertical slab and the back of the base slab. he amount of steel required along the inclined edge of the counterfort is determined by taking moments around point F. The perpendicular distance form F to the edge of the counterfort is 7'0". Allowing 5" for a protective coat- ing, the effective depth : 6' 9" a 81 inches. The height of earth acting on the vertical wall is 24' 6" as deter- mined in this design of thewall. Then the Bending Moment is . 1 {0 M a w' h2 s 25 x 24.5 x 12 = 756000 "4. 2 6 ‘ per foot of wall or 15 X 756000 or 11,040,000 "% per coun- £1. 5 terfort. The area of steel required is A a M - 11040000 8 fsjd 16000X 7X81 8' equals 9.75 square inches. The area of steel required at various points is directly preportional to the cube of the height butis inversly prOportional to the effective depth. Sincetheeffective depth is directly prOportional to the height, the result is to make the area of steel required 150. ‘7‘ .I' . steel needed at points b, c, and (1 respectively 1 ows. I (b)—(-‘&)2 it 9.75 = 5.5 square inches. (c)-(%—)2 X 9.75 a 2.44 square inches; (d)-(%)2 X 9.75 = .61 square inches. For this steel requirement use 1]; inch bars-,8=4v..~ a;5atb;2atc;and2atd. 8 it The rods are extended beyond the theoretical d‘é‘ff a short way to care for bond. Additional strength ..:} ed by providing hooks at the ends as shown in Fi- COUNTERFORTED RETAIMNG WALL Home: (A) A’ahfcrcement in wall slabs at counferforl: aha/I 6c brat f0 o’bfiasil: side of ab‘ reward Connie-Hort. Scale: (59: I 'O " 152: Design 2; Stairways: The stairways in the power house are of reinforced con- crete construction and the details are shown on Figure , a sectional view of the power house. For purposes of design, the span of the slab which com- poses the stair is assumed to be equal to the horizontal pro- jection of the length of the slab between two floors, and the design is considered as if it were a straight slab. The live load on the stairs is taken as 100# per square foot of the horizontal projection of the slab. The unit dead load of the stair portion is figured as follows: Unit dead load =(l4 x 4 x 4 x l50)+15(1o x 7 x l x 4 x 150) 12122 12% X 4 n 128 71/: dead load. Live load : 100 # 228 # TOTAL LOAD. Since the stairs are poured separately from the rest of the building and are joined to the floor only be stair dowels the slab is considered as simply supported, using M - wl2 M = 228 x 12.5 x 12.5 X 12 - 55,500 inch pounds. 8 Then: , d = depth of slab = .29 M or Gffii and AS. pd per foot of width. Use 1:2:4 concrete for which ultimate strength - 2000#; n- 15; fs = 16000; f0 = 800; k u .429; C - .085; Cl -.O24; R u 147. In the above formulae, the constant C or C1 is a constant 1:5: .5"... which is based simply on the values taken for a givenconcrete and which may be referred to in the volume "Concrete, Plain and Reinforced", by Taylor, Thompson, and Smulski, Page 205. The width of tread chosen for the stairs in a commercial building such as a power house is 10 inches and the dimension ofthe riser is found by a simple computation involving a di- vision of the distance between floors by the number of steps desired thus, Riser - 12 x 9 : 7.2 inches. The width 52 the stairs is taken as four feet. There will be little or no danger of congestion on the stairs of the pew— er house since they are for the purpose of gaining access to the auxiliary floors only for repair of turbine, etc. Applying the formula on the opposite page, d s .024‘155550 = 5.5" splus one inch protective coat- ing. This makes the total depth equal to 6". As = 5.5 X .0107 : .05885 sq. in. per inch. The spacing of 5" round bars a .5068 a 5.2 inches. 8 $3385“ Space 5 inches center t9 center. Cross reinforcement is placei in each riser to prevent temperature cracks and will be a 5" bar. 8 w _ l _ - _ 1 41..“ 1 as w_. - i . _ l 1 s _ N OF POWER HOUSE H.002 PLA C155» Specifications for Truscon Industrial Door for Power House. General: All doors of 10' or over in size shall be Industrial Doors of the heavy tubular type as shown on the detail draw- ing of the swing unit installed in the power house. See Figure . Material: All stiles and rails shall be constructed from cold- rolled welded steel tubing. All windows included in doors shall be constructed from hot-rolled new billet steel. Construction: The stiles, top rail, cross rails and bottom rail shall be constructed of No. 15 gauge cold-rolled welded steel tub- ing, 4" X 2%". The corner shall he mitered and internally reinforced, the reinforcing extending 10" in both directions from the corners. All miter joints shall be welded and ground smooth. The lower portion of the doors shall be fitted with not less than No. 16 gauge steel panel bolted in place. The upper portion of the door Shall be fitted with win- dow built up by Truscon standard members and glazed with glass lights as shown on the drawing. The glass shall be held in place with putty and glazing angles. Frames: Where shown on the drawings, steel channel frames for all door Openings shall be furnished and installed by the contractor supplying the structural steel. Hardware: 14' I" % TYP|CAL ELEV. 1. g ‘2 5 I! ... *— F———wmvu or canvas 12' 3' g F————wnoru or coca. n '"ui 2 a — / " 0 i/// 4 ,Ii 2 4. '5 7 . I g ./ EEQE‘M .. I I dfi -HOEIZONTAL seal-son; d (mu LEFT mu noon) 1 § . ' a .WIDTH or OPENING I2 worn or back Plu'r can. 1+ ~ HORIZONTAL szcvoou- . :,‘. - :5! 3.;15, .1". I» (me lev on”) VERT-ICAL SECTION VOWEE HOUSE Dd)? DETAlLS FIG.39 IL. H3. 39 137. Hardware: Sliding doors shall be hung from Truscon Standard double trolleys and heavy channel track and shall be equipped with flange guides, back stOps, etc. Swinging doors shall be equipped with Truscon Standard mortise cylinder locks ( or lever latch and padlock brackets) and heavy handles on inside and out. Where doors are hung in pairs, one leaf shall be equip- ped with Truscon Standard foot bolt and chain bolt. An astragal shall be provided by door manufacturer with all double swing or double slide doors. Painting: All doors shall receive one brush coat of red oxide of iron paint before shipment. Erection: The erection of doors furnished in combination with steel window contracts shall be handled by the manufacturer of the same. 158' Specifications for Truscon Pressed Steel Frames for 1188 in Power House. General: All frames unless otherwise specified shall be pressed steel frames as manufactured by the Truscon Company. Material: Steel sheets used in the manufacture of frames shall be cold rolled No. ll gauge, full pickled, re—annealed steel of ‘U. S. Standard gauge and patent leveled. Construction: All shOp joints shall be continuous welded and ground smooth. Where horizontal field splices are necessary, they shall be made above or below a horizontal mullion. An inside splice fitting the vertical mullion shall be sh0p welded on one sec- tion, the splice to project out, allowing the other section to be driven over the splice form with a driving fit. Where vertical field splices are required the entire frame is spliced along a single vertical line the center line of a vertical mullion. The vertical mullion is split and each half is shOp welded to the head, sill or horizontal-mullion part or parts shipped with it. Mullion cover plates join the two sections of the split vertical mullion in the field. This arrangement of splices allows all corners of the pressed steel frame to be shOp welded. Head and jambs shall be formed with fin for anchoring into the masonry. Where size of frame will permit shipping as a unit, SECTION C “C “TYPICAL WI NOON- scALz : 3': lb- Vmoow Dumas m wazz House. Fro.4o ~.SECJ'ION A-A' F121- 4 i405 vertical mullions shall be welded throughout. Painting: All frames shall be given a coat of protective paint before shipment. Erection: The erection of frames shall be handled by the manu- facturer of the same. For details of frame construction refer to Figurerl3fi REFERENCE LIST Barrows, Water Power Engineering. McGraw-Hill Book Company 1927. Creager and Justin, Hydro-Electric Handbook. John Wiley and Sons, Inc. 1927. H001 and Johnson, Concrete Engineers' Handbook. McGraw-Hill Book Company 1918. H001 and Kinne, Reinforced Concrete and Masonry Structures, McGraw-Hill Book Company 1924. Hool, Reinforced Concrete Construction, Volume 1. McGraw- Hill Book Company 1927. Taylor, Thompson, and Smulski, Concrete, Plain and Reinforced Volume 1. John Wiley and Sons, Inc. 1925. Turneaure and Maurer, Principles of Reinforced Concrete Con- struction, Volume 1. John Wiley and Sons, Inc. 1932. Urquhart and O'Rourke, Design of Steel Structures. McGraw- Hill Book Company 1930. Voss and Varney, Architectural Construction, Volume 2, Book'z. John Wiley and Sons, Inc. 1927. The Michigan Engineer, October 1928. Power, September 1928. Engineering News Record, Volume 69, 1914. 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