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OVERDUE FINES: 25¢ per day per item RETURNING LIBRARY MATERIALS: Place in book return to remove charge from circulation records THE DESIGN AND TEST OF A VERTICAL SELF-FEEDING SILO By Chester J. Mackson fl AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Agricultural Engineering Year 1955 Approved by [/(j W )2] 621.5: ‘. THESiS VQAVUVVQ V. noww-‘uvoo Preliminary investigation of the self-feeding vertical silo showed that as the cattle ate into the silo, pillars of silage formed which compacted the silage so that the cattle could not receive their ration. An investigation on a laboratory model was conducted with various cone angles and central duct sizes in an attempt to design a self-feeding base which would prevent silage pillars from.forming. Laboratory results showed that a 60° cone angle and a reducing type duct worked satisfactorily. In subsequent field tests these modifications failed to break up the silage pillars. During the feeding-out period basement columns were introduced to hold up the silage and release the pressure on the silage in the feeding area. The addition of supporting columns proved successful and suggested the addition of rocker arm supports. .The fol- lowing year two designs of supporting members were used. These successfully controlled the downward movement of the silage until the silo was almost empty. At this time more loose silage became available than the cattle could consume. THE DESIGN AND TEST OF A VERTICAL SELF-FEEDING SILO By Chester J. Mackson A THESIS‘ Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Agricultural Engineering 1955 ACKNOWLEDGMENT The author wishes to express his sincere thanks to Doctors J. S. Boyd and w. M. Carleton of the Department of Agricultural Engineering, under whose inspiration and unfailing interest this investigation was undertaken. He is greatly indebted to Professor B. F. Cargill of the Department of Agricultural Engineering for his valuable help and guidance in conducting this investiga- tion. Grateful acknowledgment is also extended to Doctors R. J. Pian and C. L. Shermer of the Department of Civil Engineering for their interest and analysis of the design. Sincere thanks is extended to the Michigan Silo Manufacturers Association for financial assistance. 358116 TABLE OF CONTENTS Page Acknowledgment INTRODUCTION 1 REVIEW OF LITERATURE 2 Structural and Functional Requirements . . . . . . 2 Feed and Space Requirements . . . . . . . . . . . A Management . . . . . . . . . . . . . . . . . . . . S OBJECTIVES 6 FIRST YEAR 7 Field Test . . . . . . . . . . . . . . . . . . . . 7' Procedure . . . . . . . . . . . . . . . . . . . 7 Results . . . . . . . . . . . . . . . . . . . . 15 Laboratory Tests . . . . . . . . . . . . . . . . . 16 Procedure . . . . . . . . . . . . . . . . . . . 16 Results . . . . . . . . . . . . . . . . . . . . 20 SECOND YEAR 23 Field Test . . . . . . . . . . . . . . . . . . . . 23 Procedure . . . . . . . . . . . . . . . . . . . 23 Results . . . . . . . . . . . . . . . . . . . . 23 THIRD YEAR 28 Field Test . . . . . . . . . . . . . . . . . . . . 28 Procedure . . . . . . . . . . . . . . . . . . . 28 b) :- Results 0 O O O O O O O O O O O O O O O O O O O TABLE OF CONTENTS (Cont.) Page SUMMARY ’ 39 CONCLUSIONS R1 PROBLEMS RECOMMENDED FOR FURTHER STUDY R2 REFERENCES CITED R3 OTRER REFERENCES nu APPENDIX us LIST OF FIGURES FIGURE Page 1. 10. ll. 12. -13. 1'. The self-feeding vertical silo was located on the site of the steel loose housing dairy cattle re- search project. . . . . . . . . . . . . . . . . . . 8 The steel I—columns and angle iron ring secured in the foundation. 0 O O O 0 O O O O O O O O O O O O O 8 Photograph showing the 14' by hO' concrete stave silo in process or COIIStrUCtione e o o o e o o o o o o o 9 A close-up of the jig used for forming the concrete cone 0 C C O O C C O O O O O O O O O O O O O O O O 0 10 A photograph of the completed cone . . . . . . . . . 11 The central wood duct was constructed from S/h tongue-and-groove spray tank staves . . . . . . . . ll The base of the completed wood duct. . . . . . . . . 12 An interior view of the silo showing the 3-foot central wooden duct . . . . . . . . . . . . . . . . l3 Sisalkraft paper was placed on the inside of the filling doors previous to filling . . . . . . . . . 1h A scale model self-feeding silo built from a concrete drain tile 0 O O O O O O O O 0 O O O O O O 0 O O O O 17 Five concrete cones used in the laboratory tests . . 17 A pressure of two pounds per square inch was applied by means of a hydraulic press . . . . . . . . . . . 19 Performing the tests on the frozen silage. . . . . . 19 The coefficient of friction was determined by moving a known mass of silage with a Specific contact area OVC-r a concrete flOOI‘ o o o o o o o o o o o e o o o 20 The 60° cone with the reducing duct. . . . . . . . . 2h The 1952—53 feeding gate consisted of a vertical pipe between each I-column and a silo hoop which could be adjusted vertically. . . . . . . . . . . . 2S LIST OF EICORES (Cont.) FIGURE 17. Pillars of silage formed about the base of the silo, supporting the entire mass. . . . . ... . . . . . . 18. An adjustable basement column is Shown supporting a portion of the silage . . . . . . . . . . . . . . 19. The rocker arm support was constructed of 3-inch I—beams and covered with 3/lo-inch sheet steel. . . 20. A 6-inch channel hinged to l-column by 1-inch pin and supported by an adjustable 3-inch column. . . . 21. Adjustable 3—incn column rested on a plate attached to I-COlurflI’l o o o e o o o e o o o o o o o o o o o o 22. Three wedge—shaped units between the I-columns served as a false floor . . . . . . . . . . . . . . 23. The 60° cone was capped with concrete to reduce the dianleter to 12 11101188 0 o o . o o e o o o o o o o o 0 2h. The 30-foot pole was used in the center of the silo. 25. Closing doors used in 1952 were modified to fit the 1953 deSign O O O O O O O O .0 O O O O O O O O O O O 26. Greater amounts of spoilage occurred in tne loosely packed silage under the supports. . . . . . . . . . 27. Spoiled silage around the loosely fitted closing doors was removed . . . . . . . . . . . . . . . . . 28. Silage bridged completely from.support to support. . 29. The load on the column supports was transferred to a hydraulic jack, making it possible to remove the adjuStable 001m 0 e o o o o o o o o o o e e o o o 30. Silage dropped into the feeding area when the column support was removed . . . . . . . . . . . . . . . . PAGE 27 27 29 3O 31 32 3h 35 35 36 38 38 LIST OF TABLES Page I. Pressures Required to Force Silage Into the Feeding Area with Grass Silage 70 Percent Moisture (wet basis) and an Initial Pressure of 2 Pounds per Square Inch . . . . . . . . . . . . . . . . . . . 21 INTRODUCTION The silo has become one of the conspicuous buildings of the rural landscape in many parts of every state in the country. It is an important factor in solving the livestock feeding problem, particularly in milk and beef production. Forage handling is one of the big feeding chores on any livestock farm. It requires four to five tons of grass or corn silage to carry one cow through the winter. Many man hours of hand labor are required to feed this silage in a conventional silo. Several attempts‘have been made to reduce the time and drudgery of feeding silage. First the top unloader was de- signed. The top unloader is a mechanical device which is placed in the silo to skim off the Silage and deliver it by means of a pipe or silo chute to ground level. Another mechanical device used to remove silage from a vertical silo is the bottom unloader. An endless chain mechanism is placed in the bottom of the silo and when set in motion digs the silage out onto a conveyor. REVIEW OF LITERATURE Structural and Functional Requirements Experimental silos have been built at Rutgers University and progress reports prepared by the Agricultural Engineering Department of Rutgers University were reviewed. Most of the published information regarding vertical self-feeding of grass and corn silage was of a non-technical nature. The best references available were those published by C. H. Reed. Reed (3)* stated the following functional requirements for a selfsfeeding structure: 1. 2. 3. 1+. 5. The structure should be one hundred percent self-feeding. The structure should have sufficient capacity to store the entire forage crop. Uastage should be no greater than if feeding were accomplished by conventional methods. The structure should offer no hazards to livestock feeding from the structure. The farmer should be able to fill the structure with machinery available. Reed (h) also states that functional self-feeders for any type of forage have the following features: * Numbers in parentheses refer to list of appended literature. 1. A device to control the feeding action of the cattle. Some method or device to control the flow and movements of forage to prevent wastage as well as make it available to livestock. No risk or injury to cattle or workman by falling forage or entanglement in the controlling devices. At a meeting of the Michigan Silo Manufacturers Associ- ation, Reed (5) of Rutgers University proposed the following five possible solutions to self-feeding silage from a vertical silo: 1. 2. 3. k. 5. Horizontal knife at silo base. Vibrating knife at silo base. Vertical duct in center of silo. Mechanical saw at silo base. Movable sheet of plywood at silo diameter to provide cleavage plane as silo is filled. Merrill (1) stated that several persons agree that a maximum width and height is 1h feet wide and MO feet high. He also states that even distribution of the silage in filling may be a factor in feeding out. Merrill (1) also proposed the following designs for self-feeding silos: 1. Mounting a sharp-edged steel blade horizontally in the top of a cone extending about 12 inches above the cone. 2. Mounting two or four steel blades 8 inches to 12 inches wide at right angles to the upper slope of the cone. Partially supporting the silage with radial walls extending from each column to the cone. Placing a central cylinder about 12 inches in diameter from the top of the cone to the top of the silo with possibly two or four projecting fins. Morrison (2) lists the following requisites of a good above-ground silo: 1. 2. 3. The walls must prevent the entrance of air and the doors must fit snugly. The silo should be cylindrical. The walls of the silo should be smooth and perpendicular. Feed and Space Requirements The United States Department of Agriculture (6)“reports that a 900-pound cow ordinarily eats 30 pounds of silage a day and a 1,200 pound cow about no pounds. Yearlings eat about half as much as mature animals; fattening cattle, 25 to 35 pounds for each 1,000 pounds live weight. The relation of size of herd to diameter of silo for winter feeding, on the basis of no pounds of silage per cubic foot and the removal of 2 inches of silage daily to avoid spoilage was reported by the United States Department of Agriculture (6) as follows. Inside diameter Amount to be Number of animals that may be of silo (feet) removed daily fed with a daily allowance (pounds) per head of 50 lbs. hO lbs. 30 lbs. 20 lbs. 12 75k 15 19 25 37 1h 1027 20 25 3h 51 16 13h0 26 33 RE 67 Management Morrison (2) recommends that in order to prevent spoilage, silage should be removed at a rate of 2 inches per day in the cooler part of the year and somewhat faster in the summer. Merrill (1) stated that controlling the feeding by the cattle and learning how to give assistance in feeding or loosening up of the columns of silage appears to be a part of satisfactory performance. OBJECTIVES The objectives of this study were: 1. To design and test a self-feeding base for a vertical silo that will allow animals to consume silage directly from the silo. 2. To design closures for the base that will minimize spoilage. 3. To design feeder gates to control feeding and prevent animals from entering the silo. h. To determine methods of reducing spoilage in the over-all operation of the silo. FIRST YEAR Field Test Procedure The Hi' by hO' self-feeding silo was designed by members of the Agricultural Engineering and Civil Engineering departments. Specifications for the design were determined by calculations found on pages M6 to 52. The self-feeding silo and base were constructed according to specifications on Michigan State College property two miles south of the campus. The structure was built as an integral part of the dairy cattle loose housing research project (Figures 1, 2 and 3). To force the silage within reach of the cattle, a h5° cone, constructed of a rock core and reinforced concrete, was placed in the center of the silo (Figures h and S). A central duct supported by the cone, extending to the top of the silo was built to help prevent the silage mass from resting on the point of the cone. Spray tank staves were used to construct this central duct (Figures 6, 7 and 8). Closing doors for the self-feeding base were constructed of 2-inch tongue-and grooved material. The doors were lined with sisalkraft paper previous to filling (Figure 9). _ '\'\ ’3: H n \" \‘A k“ N \\‘ '{ C! A) \ \u ‘3. use \ ‘.\ \ \ le§ \ § a:§§&N 5“ ' . '2 E. Q I. l. I A I fi‘. “-v“ .3 L 'I v A . ‘ , - v... . 4’—‘ a 6! 'J‘ V ( - - o ‘ 03"" s “ .‘I' ‘_ 1-. 3% Fig. l. The self-feeding vertical silo was located on the site of the steel loose housing dairy cattle research project on the Michigan State College campus. Fig. 2. The steel I-columns and angle iron ring secured in the foundation. Fig. 3. Photograph showing the lh' by MO' concrete stave silo in process of construction. Fig. h. A close-up of the jig used for forming the concrete cone. (Notice the steel reinforcements around the pile of rocks used as filler material.) 10 11 I '. . . ‘ -7 "' " 4.5 ‘ :‘tu‘I'. " Fig. 5. A photograph of the completed cone.~ Drainage holes are shown in the portion of the concrete that forms the manger of the self-feeding SilOe Fig. 6. The central wood duct was constructed from S/h tongue-and-groove spray tank staves. Fig. 7. The base of the completed wood duct, painted with linseed oil at the time of construction. 12 13 Fig. 8. An interior view of the silo showing the 3-foot central wooden duct and the distributor on the end of the filling pipe. (Notice in this photograph that the filler pipe enters through the center of the silo roof and not through the side of the roof as is customary.) k'. ’I‘_ ‘ " v V I 1 v g a , _. , _,.’ ‘ ' L?“ "' 4 y ,I" /‘ (I q‘ .l. ‘v ..‘ A ) ‘ I J 3. f???) . if: k - , ,- //.é"/" " 1’ // Fig. 9. Sisalkraft paper was placed on the inside of the filling doors previous to filling. Approximately 20 tons of grass silage were placed in the bottom of the silo. The remainder of the silo was filled at a later date with corn silage. Three samples of the grass silage were taken and tested for moisture content. Sample No. 1 had a moisture content of 66.6 percent, sample No. 2 had 6h.1 percent, and sample No. 3 had h3.6 percent. Filling was accomplished with a mechanical distributor on the end of the silo pipe which protruded through a hole in the top of the roof, not through the side of the roof as is customary. This procedure was used in an attempt to distribute the silage uniformly in the silo. 15 Feeder bars were made of 2-inch by 3-inch white oak' hinged on a 5/8 inch steel silo hoop to prevent the animals from entering the silo and to control feeding. There were two bars in each opening of the self-feeder base. Results The filling doors were removed on November 1h and the movable feeder bars installed. About 1000 pounds of spoiled silage was removed from the base of the silo. The twelve animals feeding from.the silo could not eat the silage fast enough to keep it from freezing. As the animals ate into the silo the density of the silage increased and eventually became so compact that the animals were unable to eat it. Pillars of silage resting on the face of the cone supporting the silage mass had to be chopped out with sharp mattocks. Removing one pillar at a time caused lateral pressures to develop, which were so great that they collapsed the central duct. Most of the grass silage was removed at the time that the duct collapsed and the remaining corn silage broke off in sections of four to five tons causing considerable spoilage. The feeder gates as designed restricted the anhmals sufficiently but did not control feeding. 16 Laboratory Tests Procedure Due to the unsuccessful results of the first year design, a scale model of the silo was built for laboratory experiments. The model was built from a concrete drain tile on a scale of one inch to one foot. The base was made of quarter-inch steel plate with three-quarter inch pipe for supporting columns (Figure 10). Five replaceable concrete cones to the same scale were constructed for the model (Figure 11). These replace- able scale model concrete cones were constructed as follows: .EElEEE §l22§ 6 inches h5° 5 inches h5° 5 inches 60° 6 inches 53° 6 inches 60° Four central ducts also built to scale, were used in the tests. Three ducts were constructed of wrought iron pipe with outside diameters of 1 1/2 inches, 2 inches, and 2 7/8 inches. The fourth duct was made of wood and was of the reducing diameter type, being 3 l/h inches at the top and 2 3/h inches at the base. The ducts and cones were interchangeable and any combination could be used in the model silo. l7 Fig. 10. A scale model self-feeding silo built from a concrete drain tile. The model was designed so it could be moved with a lift truck. . Mgr. Fig. 11. Five concrete cones used in the laboratory tests. Left to right they are: 6 inches - 5°, 5 inches - h5°, 5 inches - 60°, 6 inches - 53°, . inches - 60°. l8 Grass silage, 70 percent moisture content wet basis, was used in the laboratory tests. The model was filled with grass silage and a pressure of two pounds per square inch of cross sectional area was applied by means of a hydraulic press (Figure 12). The pressure was maintained for one half hour so that the consistency of the silage in the model silo approached that found in a regular silo at the depth of twenty-five feet. Pressure was then released and the silage removed from.around the feeding base of the cone. Pressure was again applied and a reading taken at the instant the silage began moving down over the cone. All combinations of the cones and central ducts were used and the tests were performed twice for each cone and duct combination. In one of the laboratory tests the silage was prepared as above and the model placed in a freezer at 0° F. for forty-eight hours. Immediately upon removal the test was performed as above (Figure 13). To determine the approxbmate downward force exerted by the mass of silage, it was necessary to determine the coefficient of friction. Friction tests were run in the laboratory by pulling a known weight of silage with a specific contact area over the floor and measuring the force parallel to the floor (Figure 1h). 19 Fig. 12. A pressure of two pounds per square inch was applied by means of a hydraulic press. .‘F ' fv' 43":4 a V , ~ . "y ,‘ 1 u -- .«eewa ‘ u )' ' i - " \ a Fig. 13. Performing the tests on the frozen silage. Note the frost on the concrete cylinder. 20 Fig. 1h. The coefficient of friction was determined by moving a known mass of silage with a specific contact area over a concrete floor. ' Results The pressures required to force the silage over the cones after the silage was removed from the feeding area varied with the various cone and duct combinations (Table I). With some of the cone and duct combinations, the silage would not slide down over the cone after the silage had. been removed from the feeding area. The silage rested on the upper one-third of the slope of the cone. Tests with other cone and duct combinations showed that the silage could be forced over the cone. However the pressures re- quired were greater than that available in the silo at a forty foot depth. Still other cone and duct combinations 21 TABLE I PRESSURES REQUIRED TO FORCE SILAGE INTO THE FEEDING AREA WITH GRASS SILAGE 70 PERCENT MOISTURE (WET BASIS) AND AN INITIAL PRESSURE OF 2 POUNDS PER SQUARE INCH Cone Duct Pressure Required Slope Height Diameter (pounds per (degrees) (inches) (inches) square iHCh) RS 6 1% 30 pounds per square ES 6 2 inch would not move AS 6 3 silage over the cone. 1+5 5 1% #5 5 2 1+5 5 3 us 5 reducing 53 6 1 19 53 6 2 10 53 6 3 .9 53 6 reducing .h 60 6 l 17 6O 6 2 10 so 6 3 .5 60 5 1%- 16.5 60 5 2 9 60 5 .5 60 5 reducing .0 allowed the silage to move down with very little applied pressure after the silage was removed from the feeding area (Table I). The reducing duct used in combination with a 60° cone proved to be most successful. No added weight was needed to make the silage come down. The 60° cone and the reducing duct were used in the test in which the silage was frozen. It required 0.6 pounds per square inch to break the silage free from the silo walls. 22 The starting coefficient of friction on the concrete was found to be 0.h7 and the sliding coefficient O.h5. 23 SECOND YEAR Field Test Procedure Results of the 1951-52 research data and the results of laboratory research indicated that a new base and duct design was necessary. The new design included a steeper cone and a reducing type duct constructed from spray tank staves (Figure 15). The top diameter of the duct was 39.5 inches which was reduced to a diameter of 32 inches at the bottom by four equal increments of 2.5 inches each. A 60° concrete cone replaced the h5° cone used the previous year. The swinging gate feeders were replaced by a vertical pipe midway between the I-columns. A silo hoop placed midway down the feeding opening prevented the animals from.entering the silo (Figure 16). The silo was closed for filling with the original filling doors, however, sisalkraft paper was not used to line the doors as in the previous year. Results The filling doors were removed from the base of the silo on October 17, 1952. The amount of spoiled silage was found to be extremely small even though the sisalkraft paper had not been used around the base of the silo to prevent air from entering through the loosely constructed ‘ .--ey:- \ - E ,2“) X \ _. -; ‘ ’,. . ‘M r. Eek- \ ‘ Fig. 15. The 60° cone with the reducing duct. The base diameter of the duct was 32 inches and the top diameter was 39.5 inches. The duct extended to the top of the silo. 25 Fig. 16. The 1952-53 feeding gate consisted of a vertical pipe between each I-column and a silo hoop which could be adjusted vertically. The silo hoop prevented the cattle from entering the silo. 26 (doors. The feeding bars were installed and the herd of ‘twenty-five adult animals and ten young stock were allowed to eat from the silo. After two weeks of feeding, silage pillars were formed about the base of the cone (Figure 17). As the cross- sectional area of the pillars decreased, the silage became :more compact and it became necessary to remove the pillars. Seven adjustable basement columns were inserted in an attempt to hold the silage up, thereby decreasing the pres- sure on the silage pillars. A column was placed in every second feeding Opening and located about 20 inches in from the outside of the silo. When the total mass was supported 'by the columns, one column was removed and relocated. Re- moval of the column allowed the silage above it to expand and drop into the feeding area. This system of relocating the columns, one every two days, supplied the animals with sufficient silage and functioned satisfactorily (Figure 18). 27 .. .. , 157.1. Ink“... -A Fig. 17. Pillars of silage formed about the base of the silo, supporting the entire mass. As the pillars were reduced in size, the silage became so dense that the cows were not able to eat. “‘2 ‘ v 1 9 ( f ( )' i ' Fig. 18. An adjustable basement column is Shown supporting a portion of the silage. The silage below the column is less dense and the cows can readily eat it. Boards were placed between the I-columns to keep the silage from falling out. 28 THIRD YEAR Field Test Procedure The results of the 1952 feeding experiment indicated that the principle of supporting the silage and releasing it as desired was at least a partial answer to self-feeding from a vertical silo. The 1953 self-feeding base was de- signed to incorporate this principle. Two types of supports were used. One support was constructed of 3-inch I-beams and covered with 3/16 inch sheet steel (Figure 19). " 3:; i ‘ "i‘ -' Fig. 19. The rocker arm support was con- structed of 3-inch I-beams and covered with 3/16- inch sheet steel. C7 The first support was hinged at the bottom to the I- column by means of a 1 l/h inch pin. A cross member at the top prevented the support from falling into the silo while a chain attached to the support and to the I-column prevented it from falling outward" The second support consisted of a 6-inch channel iron hinged by means of a l-inch pin, 11 inches from the top of the columns. It was supported at its outer end by an adjustable column resting on a plate attached to the I-columns (Figures 20 and 21). These supports were placed on alternate columns around the base of the silo. Fig. 20. A 6-inch channel hinged to I-column by 1-inch pin and supported by an adjustable 3-inch COIUIme 30 l. 5 Fig“: 2‘1".- JGAd—jEsta—bl—a 3.71th— column re—sted on a plate attached to I-column. To get an initial movement of the silage and to place the total load of the silage on the supporting members a false floor was placed in the silo. Three 2-inch by l2-inch planks separated by a wedge-shaped member were fastened together with bolts to form a unit. Three units were placed in each feeder opening (Figure 22). The 60° cone was capped with concrete to reduce the diameter to 12 inches and a steel ring set in the top of 31 L ' JAR Fig. 22. Three wedge-shaped units between the I-columns served as a false floor. The units were pulled out to get additional silage movement. the concrete served as a lateral support for the 30-foot pole which was used for a duct (Figure 23). The pole which extended to the top of the silo was installed in two sections and spliced together 20 feet from the base (Figure 2h). The closing doors used in the previous two years were modified to fit the present design by notching out portions to fit around the silage supports (Figure 25). The stationary feeder bars used in the 1952 experiment proved satisfactory and were reused. 32 Fig. 23. The 60° cone was capped with con- crete to reduce.the diameter to 12 inches. A steel ring anchored in the concrete served as a base for the center pole. Fig. 2h. The 30-foOt pole was used in the center of the silo. The 2 inch by h inch braces were removed after the pole was secured by silage. 33 3h _ >‘. r:/.'- . ’ Fig. 25. Closing doors used in 1952 were modified to fit the 1953 design. The silo was filled with 118 tons of corn silage by means of a mechanical distributor and one man in the silo to pack the silage around the supports. This method of filling was used in an attempt to cut down the initial spoilage. Results Spoilage around the loosely fitting closing doors was not as great as anticipated. It was evident that greater amounts of spoilage occurred around the supports awhere the silage was not tamped in tightly (Figures 26 and 27). 35 Fig. 26. Greater amounts of spoilage occurred in the loosely packed silage under the supports. Fig. 27. Spoiled silage around the loosely fitted closing doors was removed. 36 The false floor was removed from alternate feeding openings and the animals consumed the silage without any difficulty. The remaining false floor units were removed and as the cows ate into the silo the silage came to rest on the supports. Silage continued to drOp from the center of the silo for three or four days. Approximately one month after Opening the silo, the silage bridged completely from support to support. Two supports were released the first time and enough silage was made available to feed the herd of 26 adult animals for three days. When additional silage was needed, one or two supports were released (Figure 28). Fig. 28. Silage bridged completely from support to support. 31 The column supports were dropped by transferring the load to a hydraulic jack, removing the columns and then the jack (Figure 29). Silage over the released support ex- panded slowly and dropped into the feeding area (Figure 30). Rocker supports were retracted by placing a jack between the horizontal member of the support and the I-column. Even though this support was designed so that any initial move- ment would tend to free the support, it was a difficult job to retract them. The system of releasing one or two supports when silage was needed worked very well until the silage was within four doors of the bottom. At this stage the density of the remaining silage was not great enough to bridge the diameter of the silo. Silage continued to drop from the center and it became evident that the total mass should be lowered to the floor of the silo. All of the supports were released at once, but rather than the silage moving down as a unit, it broke apart and consequently the spoilage at this time was excessive. The purpose of the central pole was to prevent the silage from resting on the point of the cone. However, the silage bridged two to three feet above the top of the cone and it appears that the pole no longer serves a purpose. At midpoint in the feeding period the pole started to be forced off center and continued to angle off until the top touched the silo wall. At this point it became necessary to saw the pole off about one foot above the cone so that it would not damage the silo. 38 ‘ 4‘ v) v- ' i. c ‘ ~ - .. 1 Fig. 29. The load on the column supports was transferred to a hydraulic jack, making it possible to remove the adjustable column. a r» o v», ‘(- r v . ;’,'.~‘,1I . I A "fr. I .- ‘ ' I L ‘\f..‘ 'L‘_ ‘ . . : ' v.‘Z| 1": - I.I 1' . , ‘ .‘ ‘ . ’ .» t l 1‘ " ‘. n \ 2' gg’ ‘ :Jr‘v . , Fig. 30. Silage drOpped into the feedin" area when the column support was removed. When his icture was taken the temperature had been below 20 F. or a week and was 5° F. at the time the picture was taken. 39 SUMMARY A self-feeding silo was designed by members of the Agricultural Engineering and Civil Engineering departments of Michigan State College. The structure was built as an integral part of the dairy cattle loose housing research project on south campus. The silo was a lh"by hO' concrete stave silo constructed on top of a base which was five feet high. A concrete cone in the bottom of the silo supported a three-foot duct which extended to the top of the silo. The self-feeding silo was tested during the 1951-52 feeding period but due to the unsatisfactory results was redesigned. Experimental work was carried on in the labora- tory with a model silo to design a new self-feeding base. As a result of the laboratory work, the original u5° cone was replaced by a 60° cone and the three-foot diameter duct was replaced by a reducing duct, 39.5 inches at the top and 32 inches at the bottom. This reduction was accomplished by three equal increments of 2.5 inches each. The silo was filled with corn silage and tested during the 1952-53 feeding season. Silage pillars formed and be- came so hard that it was difficult for the animals to obtain their ration. hO Seven adjustable basement columns were placed under the silage to relieve the load on the pillars. The silage pil- lars were then removed allowing the silage to come to rest on top of the basement columns. When additional silage was needed one of the columns was relocated, which released five or six hundred pounds of silage. This system of holding up the silage and controlling its downward movement was the basis for a new design. The new design consisted of rocker arms attached to each I-column and braced against the footing. The rocker arms protruded 16 inches into the silo and supported the silage mass. Releasing one or two of the rocker arms every second or third day supplied sufficient silage for the animals. This self-feeding base worked satisfactorily with a minimum of labor until the silage was within four doors of the bottom. At this time the silage failed to bridge and more silage dropped into the feeding area than could be consumed by the cows. Excessive spoilage was encountered during opening and during the final stages of feeding-out. However, these difficulties might be overcome with improved closing doors and a modification in the design to better control the silage during the final stages. hi CONCLUSIONS On the basis of the field tests, the following con- clusions were made: 1. The feeding of silage to cattle by means of a vertical self-feeding silo is possible with good manage- ment. 2. The principle of supporting the silage mass, above the feeding manger, was substantiated. 3. A sixty degree cone operated superior to other slopes for the feeding cone. h. Supporting members should protrude further into the silo to control silage during final stages of feeding. S. The central pole or duct is not necessary when supports are used. 6. Air pockets formed under the supports resulted in spoilage. 7. A stationary type of feeder bar proved most satisfactory. 8. Even distribution of silage at filling time facilitated feeding out. 9. Tight fitting filling doors should be used. A2 PROBLEMS RECOMMENDED FOR FURTHER STUDY 1. Perform another feeding test in the summer months. 2. Perform another feeding test with supports which protrude further into the silo. Twenty inches is recommended. 3. Perform feeding test without central pole. h. Construct a new self-feeding silo with a 12-foot diameter to check the bridging of silage. 5. Study thoroughly the vertical pressures that exist on the supporting columns. Results should be based on a large number of tests. Lateral wall pressures during operation should be included. 6. Perform tests using various lengths of cut. 1. #3 REFERENCES CITED Merrill, E. D. Report of Self-feeding Silos. Republic Sttel Corporation, Republic Building, Cleveland, Ohio. 1951. Morrison, F. B. Feeds and Feeding. 21 ed., pp. 329-33h. Ithaca, The Morrison Publishing Company. 1949. Reed, C. H. Farm Structures Designed for the Self- feeding Hay and Ensilage. Agricultural Engineering 29zh88-9, 19MB. Reed, C. H. Special Structures for Storing and Self- feeding Hay and Silage. New Jersey Agricultural EXperi- ment Station, Rutgers University, New Brunswick, New Jersey. Reed, C. H. Minutes of Michigan Association of Silo Manufacturers Meeting. Department of Agricultural Engineering, Michigan State College, July, 1951. U. S. Department of Agriculture. Silos, Types and Construction. Washington, D. C., U. S. Government Printing Office, September, l9h8. OTHER REFERENCES Barre, H. J., and Sammet, L. L. Farm structures. lst. ed. p. #58. New York, John Wiley and Sons, Incorporated. 1950. Besley, H. E. Self-feeders for hay and silage. Hoards Dairymen 95:259-260. April 10, 1950. Bookhout, B. R., and Vary, K. Cost and methods of harvesting grass silage. Michigan Agricultural Experiment Station Quarterly Bulletin, 32:582-8, May, 1950. Brown, L. H., Cargill, B. F., and Bookhout, B. R. Pen-type. dairy barns. Michigai Agricultural Experiment Station Special Bulletin, 3 3, 1950. Hanson, D. Work lanned cattle feeding system. Successful Farming h8:h -h9, Oct., 1950. Merrill, E. D. Report of visits to self-feeding silos in January, 1952. Republic Steel Corporation, Republic Building, Cleveland, Ohio. ' Merrill, E. D. A report on self-feeding silos. Republic Steel Corporation, Republic Building, Cleveland, Ohio. 1953. Michigan Department of Agriculture. Michigan Agricultural Statistics, 1950. May, 1951. O'Brien, Harry R. Self feed your silage. Country Gentleman, June 1953, p. to. Perkins, A. E., Pratt, A. D. and Rogers, C. F. Silage densities and lesses as found in laboratory silos. Ohio Agricultural Experiment Station Research Cir- cular 18, April, 1953. Reed, C. H. Department of Agricultural Engineering. Rutgers University. Information on the operation of a vertical self-feeding silo. Private communication. 1951. Reed, C. H. Progress report on the development of structures designed for the self-feeding of hay and ensilage. Department of Agricultural Engineering. Rutgers Uni- versity, 1950. #5 Reed, C. H. Structures for self-feeding of hay and ensilage. Agricultural Engineering, 32:375-376. ‘ Rogers, C. F. Your silo, Mr. Farmer. Ohio Agricultural Experiment Station, Ohio State University, Wooster, 011.100 Schwanz, H. L. Roughage self-feeders cut chores. Country Gentleman 121:22-23, June, 1951. Singley, M. E. The A. O. Smith silo and "Tower-on-the-Square," or Mazur, Silo. New Jersey Agricultural Experiment Station. Rutgers University, New Brunswick, New Jersey, May , 1953 e U. S. Department of Agriculture. Silos types and construc- tion. Washington, D. C., U. S. Government Printing Office, Sept. l9h8. APPENDIX Structural Analysis of Supports: the following analysis indicates that the steel columns are adequate to support the loads imposed upon them, but that care must be taken to insure sufficient anchorage in the concrete to develop the moment resistance necessary for wind loads. A recommended way of providing this anchorage is shown on page 52. In addition the columns should be protected against the corrosive effects of weather and the silage. 1&7 Structural Analysis of Supports for Self-Feeding Silo \ Concrete-Block \ ' Silo " 6 x 3 x'g L ring . E. " 6" 00D. ussets on 6" I 12.5#—————e> U Alternate Columns 25 &—~ I' —V LLO' Detail at Top of Column ll 3 x 6 x‘g L ring m - e" I 12.5# M9 25.6° apart on circmm- ference ‘3' - o'LL //7//////T/If/I Concrete Footing 1,8 In the direction of their greatest stiffness the columns can develop no moment resistance at the top. Normal to this the moment resistance developed in the columns, because of the gussets is negligible inasmuch as this is about the axis of least stiffness. Hence, in the analysis, the moment in the columns at the top is assumed to be zero. Lateral wind loads will cause all columns to bend about axes parallel to each other as shown. The total lateral stiffness is proportional to the summa- tion of the moments of inertia about the axes shown. For an axis, x , inclined at an angle, to the principle axis, the moment of inertia is 2 2 + I sin I = Ix cos y x and 2 + cos Iy sin = 21.8 x 6.50 + 1.8 x 6.50 = 15h in,4 2 149 _:f_ _I&__. I I '85 «1" i' . It, Plan of Columns Showing Axes About Which Bending Occurs For Wind as Shown. Total lateral wind load e 30 1b./sq. ft. is P = no x 1h.5 x 30 = 17,u00 lb. = 17.11 1: All columns will deflect the same amount and therefore the column whose depth normal to the axis of bending is great- est will be stressed the greatest. The load taken by the individual columns will be proportional to their Ix values. Max. 3 = §I5E x 17.h x 60 x 2100 = 20.30 k/inz. due to bending only. 50 The columns on the leeward side will have a direct stress due to the wind which will be - Ph x a 3 ‘ "‘i”" s in which height of resultant wind pressure above top of columns 5‘ II R = radius of column group I = moment of inertia of the group con- 3 sidered as a unit I8 = A (R sin )2 = 132 sin2 = 6.50 132 and the direct unit stress from this cause is 8 .50 x 3.61 x 86 = 2.08 k/in.2 Direct D. L. stress in columns is , goooog = 985 lb/in.2 8‘1x301 0.98 k/in.2 Total stress (max.) in column is 4 s = 20.3 + 2.08 = 1 = 23.0 k/in.2 Column Anchorage Max. lateral load on column is «%%fi§ x l7,u00 = 2,u70 lb. Total pressure F, on concrete is F = @478 x 66 + 2u70 = 22,870# Max. unit pressure f 3 22,870 x 2 C x 3.3 = 2260 lbs/11102 51 2u70# 60" 1" u/ . _m. .l' "5 12" 52 It is very important that the columns be prevented from breaking out of the foundation laterally. Therefore it is recommended that the concrete slabs on both the inside and the outside of the silo be poured tight against the wall and that they be 12 inches thick at the wall as shown on the sketch bOIOWe F _ D ' E! A . - D b A- ' .l' n 55 " P ’ v-::":' fiver" ‘ \ LL;_J;/ a ‘.A PF? _t - D , v ' 'i l> PM WEE gym iiuum Ln; H 8 Jun 3’ WW ..,.a -z 5;?»- A . .‘ J' ‘ ,I ‘4. . ¥ ' ' ‘ l .a . P- . 1 I". l ? 4 w ‘ ‘ ‘ 7"“ ‘5‘ l 3 r'“. ‘WilliilliifiiMM“