US2750013A - Prefabricated metallic building for storage and the like - Google Patents

Description

June 12, 1956 B, JQHNSQN ETAL 2,750,013

PREFABRICATED METALLIC BUILDING FOR STORAGE AND THE LIKE Filed Nov. 21, 1949 5 Sheets-Sheet 1 FlG. 5

By yWQ/nmw.

Attorney June 12, 1956 H. B. JOHNSON ETAL. 2,750,013

PREFABRICATED METALLIC BUILDING FOR STORAGE AND THE LIKE 5 Sheets-Sheet 2 Filed Nov. 2l, 1949 FIG. 3

Inventors:

0 O l() LO Hui/r EJs/wen,

/l/exanaer 5km/ey Maujhan. By paa/ Werd/infer,

June 12, 1956 H. B. JOHNSON EVAL PREFABRICATED METALLIC BUILDING FOR STORAGE AND THE LIKE Filed NOV. 2l. 1949 3 Sheets-Sheet 3 FIG. 5

Pau/ Werd/1777er, By

United States Patent Office Patented June 12, 1956 PREFABRICATED METALLIC BUILDING FOR STORAGE AND THE LIKE Hugh B. Johnson, Falls Church, Va.,

Alexander Stanley McGaughau, Washington,

D. C., and Paul Weidliuger,

This invention pertains to building structures, and especially to storage structures such as grain bins, silos or the like. It is an object of the invention to provide a storage bin utilizing prefabricated wall units of relatively large size to reduce the complexity of assembling, but which units will be extremely light to facilitate and reduce the cost of shipment handling and assembly thereof into the finished structure.

Another object of the invention is` to provider a storage building or bin construction utilizing prefabricated wall sections held together with a minimum number of fasteners,` so that the size of an existing bin of this construction may readily be increased (or decreased) from time to time with a minimum expenditure of labor.

Still another object of the invention is to provide a grain bin or like construction formed substantially entirely of aluminum, aluminum alloy or other lightweight metal, having features which provide adequate strength for all of the loads associated with a building of this type, but utilizing a minimum amount of structural material.

A further object of the invention is to provide a prefabricated structure built up from parts having integrally secured thereto the necessaryl fastening elements for connection with other parts of the same structure,V whereby to reduce the number of bolts or equivalent fasteners that would otherwise be required. In the preferred embodiment, such bolts as are employed function only as positioning elements, and do not support any of the structural loads.

Yet another object of the invention is to provide a construction of this type utilizing prefabricated wall units and door and roof elements all formed of metal' to provide permanent protection against rot, rust and other forms of deterioration.

Still another object of the invention is to provide a design facilitating assembly by a minimum number of workers, who need not have any special skill or training.

An additional object of the invention is to provide a double Wall construction for buildings of this type which will give a degree of thermal insulation and high mechanical strength with a minimum use of structural material.

The above and other objects and advantages of the invention will best be understood from the following detailed specification of a preferred embodiment thereof, reference being made to the accompanying drawings, in which:

Fig. 1 is a perspective view of a complete grain bin or like structure embodying the invention,

Fig. 2 is a fragmentary vertical sectional view taken along line 2-2 of Fig. l,

Fig. 3 is a fragmentary enlarged perspective view of a portion of Fig. 1, the horizontal sectional plane being designated by line 3 3 of Fig. 1, Y

Fig. 4 is a partial horizontal sectional View showing the end fastening elements of one wall unit, the section plane being designated by line 4-4 in Fig. 1,V

Fig. 5 is an enlarged fragmentary perspective View showing both horizontal and vertical joints between adjacent wall elements,

Fig. 6 is a partial vertical sectional view taken through the foundation of the structure and illustrating the manner of connection of the storage bin thereto, and

Fig. 7 is a View similar to Fig. 2, but of a modified form of construction. i

It has heretofore been proposed to provide grain bins, Silos and the like which are made up of prefabricated sections of metal, especiallyof corrugated steel and the like. In buildings such as grain storage bins or the like, however, the conditions of loading are quite different from those encountered in building constructions of other types. Grain and similar material which is stored in these buildings is necessarily in contact with the walls, and such material transmits stresses somewhat in theV nature of a fluid. That is, the weight of the grain or other material transmits radial stresses to the walls, which produce Very substantial hoop loads or circumferential tensions therein. These tensions are of course greatest for the lower portions of the walls, and they increase with the height of the grain or other material which is stored in the bin. At Athe same time, the wall construction must be capable of withstanding very strong vertical compressive loads, far beyond the load due to the weightof the wall sections alone. Since the lateral flow of material stored in the bin is constrained, the Weight of the grain in the bin is transmitted by frictional contact with the inner surfaces of the building walls into downwardly directed compressi-ve forces within such walls, and here again these forces increase with the height of the material contained in the bin.

Heretofore, the use of light gauge material for the walls of such buildings has been restricted to small structures, although larger structures with light gauge walls could be made by using auxiliary internal or external structure frame works, which naturally increase the cost of construction. lt is therefore desirable to provide a construction using light gauge but self-supporting wall materials which can be used in the formation of either small` or large buildings, and which can be erected with a minimum amount of labor.

The present invention provides a very great simplification and economy as compared withl the prior constructions mentioned, in that a composite wall structure is utilized which is entirely self-supporting with reference both to the vertical compressive loads and the circumferential tension loads, thus completely eliminating the necessity for any supporting framework. This is accomplished in a way that permits the use of extremely light gauges of sheet metal, so that the desired result is obtained without any sacrifice and indeed with substantial gains respecting cost and ease of assembly. Wall units of the preferred construction are provided with functionally integral connecting elements, which feature substantially eliminates the need for the extremely large number of bolts or similar fasteners that were required in prior constructions.

The present invention is based on the use of relatively large, prefabricated composite wall units of arcuate shape corresponding to the outer periphery of the cylindrical structure, each of these units comprising an inner flat sheet and an outer corrugated sheet having connecting members at all four edges, welded or otherwise fastened to one or both of the principal sheets; the whole assembly being accurately curved to the desired radius. The connecting members along vertical joints between ends of adjacent Wall units are designed to interlock with one another by complementary connecting elements in such a way that the peripheral tension stresses or hoop loads are transmitted through a relatively thick edge strip and are absorbed by the thin inner sheet when the proper number s v "l 1 of wall units have been connected with one another to complete one peripheral ring of the tinal assembly. The connection between the thin inner sheet and the thicker edge strip being made with numerous spot welds or other factory installed connection devices, permits all field connections to be made between relatively heavier or thicker metal parts. The top and bottom edges of the composite wall unit are each provided with complementary intertting strips for connecting with the similar wall panels lying above and below; these strips having portions extending outwardly from the plane of the inner wall sheet. These top and bottom edge connector strips are secured through the flat inner sheet to the corrugated outer sheet by means of numerous welds or other factory installed connecting devices of such nature that the compressive or vertical loads in the wall of the completed structure are transmitted from one composite wall unit to another; the compressive loads being transmitted through the horizontal connecting strips to the corrugated outer sheet in each tier of wall panels.

In other words, the wall panels are composed of inner ilat sheets locked together at their ends to form a ring for absorbing the circumferential tension, combined with outer corrugated sheets which support the vertical compressive loads; the panels being so constructed that the two principal sheets are accurately positioned with respect to one another, but act independently in resisting the loading to which they are subjected. Since the inner flat sheet will buckle under vertical or compressive loading, this sheet may be considered to hang as a curtain supported by the spot welds or other fasteners along its upper edge. Thus the flat sheet participates in resisting the weight of grain transmitted by frictional contact with the inner wall surfaces only to the extent of the increment of load developed between the upper and lower limits of each individual sheet. Since the sheet hangs as a curtain supported at its upper edge, this increment of load results in a tension reaction rather than a compressive reaction within the sheet. The inner at sheet of the composite wall unit is thus subjected to tension stresses in four directions.

As the major tension loading due to the outward pressure of the grain subjects the sheet to a severe tensile loading along its horizontal axis, it thus tends to crowd the molecules of the material closer together across the center of the sheet. The minor tensile loading due to the frictional action of the grain against the inner face of the Wall exerts a force which in direction is at right angles to the horizontal forces; thus tending to separate the molecules of the material at the center of the sheet. The major and minor tensile loading resisted by the inner wall sheet may, therefore7 be seen to have a tendency to compensate one for the other. The outer corrugated sheet does not participate in resisting the tensile loads due to outward pressure of the grain, since the vertical corrugated pattern is responsible for an accordion-like action of the sheet when the sheet is subjected to lateral or tension loading in a horizontal direction.

Referring now to Fig. l of the drawings, there is illustrafed a grain bin or silo 10 of generally cylindrical form, supported upon a foundation 12 and provided with a conical roof 14 and Ventilating cap 15. The lateral wall structure of the bin is formed of a plurality of arcuate wall panels generally designated by numeral 16 formed into successive horizontally arranged rings, there being three of these rings in the structure illustrated in Fig. l. The two lower rings, as shown in that figure, are interrupted to provide space for the removable bunker boards 18, a scoop bin section 2t) and a chute section 22. A hinged door 24 is mounted along one edge of this opening, and suitable latch hardware or the like is provided to prevent access to the contents by unauthorized persons.

In order to permit the use of a minimum number of diiferent sizes of wall panel units, and thus to reduce the manufacturing cost, it is desirable to dimension these panels so that the opening required for the bunker boards 18 will not involve any piecing out of the rings intersected by such opening. At the same time, since the arcuate base of these panels would make them somewhat unwieldly for handling and shipment, it is desirable to maintain a reasonable maximum length of wall panel section. For a bin having a diameter of approximately 16 feet 6 inches, for example, it is desirable to provide wall panels whose lengths are respectively 14 feet and l0 feet, measured along the arc. Three of the 14 foot sections and one of the l() foot sections can thus be interlocked to form one complete ring having the indicated diameter (such as the top ring in Fig. l), while two of the 14 foot sections and two of the 10 foot sections can be interlocked to form the lower rings of Fig. 2 and thus to provide a door panel including the door opening approximately 4 feet wide as measured along the circumference. Since the arcuate sections of these two different circumferential rings are otherwise identical, only one such section will be described in detail hereinafter.

Fig. 2 of the drawings is a vertical section through one of the arcuate wall panels 16 and its connection to the wall panels lying above and below it. In that figure, numeral 26 designates the single thin flat sheet which forms the inner skin of panel 16. Numeral 34 designates the vertically corrugated outer sheet. Along the upper and lower edges respectively of the panel 16 there are spot welded thereto complementary members 28 and 30. Members 28 have a right angle bend so that one leg extends outwardly from the plane of sheet 26, while member 30 has an outwardly extending leg bending reversely upon itself as at 32 for engagement with the outwardly extending leg of a member 28 welded to the horizontal edge of the next lower wall panel. Members 28 and 30 are spot welded to the outer corrugated sheet through the flat inner sheet, or in other words, all three thicknesses of metals occurring along the upper and lower edges of panel 16 are spot welded together.

As shown in the horizontal sectional view of Fig. 3, one end of sheet 26 has spot welded thereto a vertical connecting element 36 having a web 38 to which the end of sheet 26 is secured, preferably as by welding, an abutment portion 40 and a dovetail key portion 42. The opposite end of sheet 26 has secured thereto a complementary connecting element 44 having a portion 46 to which the other end of sheet 26 is secured, again preferably by welding, an abutment portion 48 and an outward flange 5t) provided with a dovetail portion 52 adapted to engage the dovetail portion 42 of element 36 to absorb the circumferential tension of the contents of the bin when the wall panels have been assembled. Elements 36 and 44 are preferably apertured to receive positioning bolts 54, these latter being provided merely to secure the parts together and not to absorb the circumferential tension which is borne completely by the interlocked tongues 42 and 52. The outward flange 50 is provided with portions 56 and 58 directed toward portions 46 and 38 (when the joint has been accomplished) to receive and retain the curved ends of the vertically corrugated outer skin 34 of the wall panel. The inner skin 26 and the outer skin 34 are secured to one another intermediately of their ends as by spot welding in the troughs of the corrugated skin 34, and in horizontal lines along the upper and lower edges of the Wall panels and at one or more intermediate points. The outer corrugated skin 34 thus bears the entire vertical compressive load transmitted by connector 35) to connector 28. While connectors 28 and 30 are both welded to the inner skin 26 as shown in Figure 2, this inner sheet will buckle imperceptibility to allow the corrugated outer sheet 34 to absorb the entire compressive load.

In order to accomplish transmission of the circumferential load in the lower rings which are interrupted by the door opening for the bunker boards 18, the construction best shown in Fig. 4 is provided, and comprises door frame elements 58 having integral connecting portions 60 adapted to interfit with the connecting member 36 of the adjacent panel section 16, and the opposite doorframe member is provided with a complementary portion adapted to mate with a connecting member of the type designated by numeral 44 in Fig. 3. Thus, the door frame members are enabled to receive the circumferential stress from the adjacent wall panels, and this stress is transmitted between the doorframe members through the bunker boards 18 by reason of the engagement between a dovetail portion 62 at each vertical edge of the bunkei board with a dovetail portion 64 of the respective doorframe members. Portion 62 of the bunker board is a part of an element having a flange portion 66 spot welded to the body sheet forming the bunker board, and an outstanding fiange 68 adapted to lie against an outstanding ange 70 of the doorframe member. Elements 62, 66 and 68 are preferably integral portions of a Single bunker board terminal strip which may be formed by the extrusion of aluminum in a well known manner, and the doorframe members themselves may likewise be extruded shapes for economy of production.

The bunker boards are provided along their upper and lower horizontal edges with formations such as 72 and 74 which are adapted to overlap after assembly to provide a seal. For greater clarity, the bunker board assembly in Fig. 4 is shown displaced rearwardly from its assembled position, it being understood that the same will be moved in the direction of the arrow in that figure to its final position with the vertical dovetail 62 interlocked to the doorframe dovetail members 64. In order to position the bunker boards firmly in place but provide for their ready removal, key hole apertures such as indicated at 76 may be provided in the bunker board terminal extrusions for engagement with bolts or studs secured to doorframe members 58. The vertical loading due to the frictional action of the grain on the inner face of the bunker board is transmitted through the bunker board to the bolt or stud in the doorframe member 58 and is thus resisted by doorframe member 58. A horizontal lintel or doorhead member installed across the top of the opening and connected to doorframe 58 and its complementary members at the opposite doorjam is of such design and strength that it adequately resists all vertical loading transmitted by wall panels above the door opening. This lintel or doorhead member is also provided with a flange which is comparable to member 28 of the Wall panel in Fig. 2 and is complementary to connecting member 30 of the wall panel located immediately above the door opening.

It will be clear from the above description that there are no permanent cross ties between the doorframe members, the horizontal stresses being transmitted through the bunker boards themselves. Thus, when empty of grain the storage bin may be utilized for general storage purposes merely by removing the bunker boards, leaving a substantial access door uninterrupted by horizontal ties.

It will be seen from an inspection of Fig ,3 that the vertical joint between adjacent wall panels is adequately protected against outward leakage of grain and inward leakage of rain or the like. The continuity of the outwardly extending portions 32 of connecting members 30 and their mating portions 28 is, however, interrupted where adjacent panels come together, as indicated by the dotted line 78 in Fig. 5. To prevent leakage at this point, a weather strip 80 of sheet metal, preferably with its underside having secured thereto a layer of builders felt or asphaltum or the like, is inserted between the lower edge of outer skin 34 and the underlying portion 32 of connecting member 30 (see also Fig. 2). This element deects rain and dripping water away from that portion of the joint which would otherwise be exposed to such leakage. Weather strip 80 is held securely in its proper position by means of a weather clip 81 which is held in place as a large washer by the lowest positioning bolt 54 along the vertical panel connection line` The edge strips such as 3S and 46 in -Fig. 3, and 23 in Fig. 2, have the dual function of providing sufficient stitening to make the panel units self-supporting and sufficiently rigid for ease in handling, and also provide the necessary fastening function for the securing of the units to one another, Without the necessity for any auxiliary framework or the like.

In the form of construction illustrated in Fig. 2 of the drawings, the horizontal portions of fastening elements 32 are shown out of contact with the light gauge sheets 26 and 34 at their top and bottom edges, in order to emphasize that the transmission of stress vertically across the junctions is accomplished solely by the interfitting connections 28 and 32. As shown in Fig. 7, however, the parts may be so dimensioned that the top and bottom edges of the panels may actually carry part of the load. This is particularly so where the connectors are rivetted or bolted to the panel sheets, because an excessive numbei' of rivets or the like would be needed to accomplish the required stress distribution such as is readily attained by the numerous spot welds as shown in Fig. 2.

In Fig. 7, the flat sheet 26 and the corrugated sheet 34 are shown as connected together at a vertical joint by interiitting members 28' and 30, these being secured to the sheets as by rivets 82. The loop portion 32' of member 30 may be slightly recessed as at 84 to provide a shallow pocket within which the lower edges of sheets 26 and 34 may rest. Similarly, member 28 may have an additional flange 86 which extends over and embraces the top edges of sheets 26 and 34 as indicated at 88. Members 28 and 30 may be aluminum extrusions for economy in manufacture and except as noted above function in the same way as members 28 and 30 of Fig. 2.

While the invention herein has been disclosed in connection with a preferred embodiment thereof for purposes of illustration and in compliance with the patent statutes, it is to be understood that the principle of the invention may be applied to structures which differ widely in details, and many changes and modifications in the specific instructions illustrated may be made without departing from the scope of the invention as dened in the appended claim.

What is claimed is:

In a cylindrical building construction, a plurality of arcuate wall units each provided at its opposite ends with tensile stress transmitting connections, said wall units being connected to one Aanother by said connections to form an assembly, and so dimensioned that the total arcuate length of the assembly is substantially less than a complete circle, door frame elements provided with tensile stress transmitting connections connected to the ends of said assembly, and a bunker board provided with tensile stress transmitting connections connected to said door frame members, all of said connections comprising overlapping dovetail portions adapted to engage with one another for free sliding movement of the engaged parts in the vertical direction.

References Cited in the tile of this patent UNITED STATES PATENTS 1,127,643 Kramer Feb. 9, 1915 1,210,717 Snow Ian. 2, 1917 1,265,442 Fitch May 7, 1918 1,311,116 Fitch Iuly 22, 1919 1,417,664 Garlinghouse May 30, 1922 1,625,061 Trout Apr. 19, 1927 1,840,942 Fahrenwald Jan. 12, 1932 1,977,391 Kramer Oct. 16, 1934 1,984,232 Peremi et al. Dec. 11, 1934 2,302,949 Palmer Nov. 24, 1942 FOREIGN PATENTS 550,277 Great Britain 1942

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