US2902951A - Flat truss - Google Patents

Description

v59199191959 J H, MMG 2,902,951

f FLAT TRUss Filed July 25.v 1953 'lll [lill i diagonal bracing.

United States Patent Ghee 2,902,951 Patented Sept. 8, 1959 FLAT TRUSS John Henry Maag, Glendale, Calif. Application July 23, 1953, Serial No. 369,754

3 Claims. (Cl. IUS-23) The invention relates to building structures and has particularly reference to a at truss suitable for the support of a roof or, if desired, for a combined roof with a ceiling therebeneath. The device is a truss particularly well adapted to provide a substantial amount of unobstructed ioor space between columns as well as being one sufciently shallow to provide a relatively great amount of head room.

Considerable attention has been given in recent years to providing large covered spaces and in the provision of such covered spaces it has been the object to provide as much clear iloor space as possible. In many instances the type of structure or perhaps the use to which the structure is to be put has not warranted a permanent type of structure which at present day costs would be greater than warranted by the circumstances. In many instances also in addition to providing an unobstructed oor area of wide expanse considerable head room need also be provided.

Various types of structural arches have found some degree `of acceptance in structures of this kind. Temporary warehouse facilities, markets, and loading areas exemplify some of the installations. Where ordinary trusses have been employed, the cost has frequently been sufficiently high to prevent their use in many types of installations. Ordinary trusses also sufer the disadvantage of requiring a considerable amount of space between the lowermost girders or tension members and the t upper compression members.

It is therefore among the objects of the invention to provide a new and improved flat truss which is inexpensive to construct in comparison with the strength provided and which at the saine time is capable of spanning relatively great distances between vertical columns or similar anchorages.

Another object of the invention is to construct and provide a new and improved flat truss of composite structure such that materials like metal having a relatively great tensile strength are used where the tensile stress is greatest and inexpensive materials such as wood, capable of withstanding a considerable amount of compressive stress, are used where compressive strength is the principal requirement.

Still another object of the invention is to provide a new and improved flat truss of composite structure wherein wood planking may be employed for the compression member and moreover may be employed in relatively short lengths laminated to make up the requisite cross-section with laminated sections joined together by a new and improved joint.

Still another object of the invention is to provide a new and improved flat truss wherein wood planking is used in laminated sections spanning intervals between apexes of diagonal bracing with the laminated sections joined in such fashion that a joining plate serves simultaneously as a gusset plate for the attachment of the With `these and other objectsV in view, the,v invention l consists inthe construction, arrangement and combination of the various parts of the device whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

In the drawings:

Figure 1 is an elevational View of the principal elements of the llat truss of the invention partially broken oli where the elements are repeated.

Figure 2 is a cross-sectional view of one of the joints taken on the line 2--2 of Figure 1.

Figure 3 is a perspective View of the top of one of the columns or anchorages for one end of the truss.

Figure 4 is a cross-sectional view taken on the line '4--4 of Figure l.

Figure 5 is a fragmentary cross-sectional view of the upper compression member at the location where intermediate joists are attached.

Figure 6 is a perspective View of an anchoring element by means of which the lower tension member of the truss may be attached to a column or similar anchorage.

In the form of the invention chosen for the purpose of illustration the iiat truss consists generally of a lower tension member 19', an upper compression member 11, and a system of diagonal bracing comprising angle sections 12. The truss is one adap-ted to be supported by vertical columns 13. The vertical columns may be of standard structural shapes, there being shown a wooden column purely by way of example.

More particularly the tension member 10 is herein illustrated as an angle continuous from end to end. The tension member is adapted to be secured at each end to one or another of the columns 13. In properly securing the tension member to the column there is employed the structural shape 14 illustrated in Figure 6. This may be advantageously cut from a suitable rolled or extruded T bar or it need be may be built up from a rectangular plate 15 joined to a trapezoidal plate 16 by welding. When the structural shape 14 is secured to an end 17 of the tension member 10 by bolts 1S, for example, the shape may be secured by means of a bolt 19 extending through the vertical column 13 and the tension member thereby anchored to the ycolumn which serves as an anchorage.

The upper compression member 1-1 is herein shown to be constructed of planks 20 and 21 positioned face to face with the long transverse dimension extending vertically. rI`he planks thus joined one with the other by aid of a bolt 22, for example, are arranged in sections of uniform length, one section being identified by the reference character 23 and adjoining sections by the reference characters 24 and 25. The sections as shown are positioned longitudinally with respect to each other with ends 260i the section 23 abutting ends 27 of the section 24 in face to face relationship. A11 opposite end 28 of the section 23 abuts a corresponding end 29 of the section 25.

Where the end 28 of the section 23 rests upon the top of the vertical column 13 there is provided an end gusset 30. A similar end gusset 31 is included in the section 25 at the end 29. The end gusset 30 is positioned between .and separates the planks 20 and 21 as illustrated in Figshown in perspective view in Figure 3. The cradle may consist of angle sections 37 and 38 positioned so that legs39 and 4t) .face each other to enclose between them the respective ends of the sections 23 and 25.

The angle sections are mounted at the top of a cap 40 which may consist also of angle sections 41 and 42 in the positions illustrated in Figure 3 wherein the angle sections 37 and 38 may be welded to the angle sections 41 and 42. Bolts 43 may be employed extending from the angle section 41 through the top of the vertical column and thence through the angle section 42 in order to anchor the cap at the top of the column. Bolts 44 may be employed for bolting the sections 23 and 25 respectively to the cradle and therefore to each other.

For joining section 23 to section 24 intermediate the supported ends of the upper compression member 11 an intermediate gusset plate 45 is employed. The intermediate gusset plate 45 lies between the planks 20 and 21 spacing those planks one from another as does the interpositioning of the end gusset plate 30. Bolts 46 extend through the planks 2t and 2l and the intermediate gusset plate to hold those parts together. Bolts 47 in a similar fashion secure together the respective planks of the section 24 and also secure them to the opposite end of the intermediate gusset plate 45.

A lower portion 48 of the gusset plate 45 extends well below the lower edge of both sections 23 and 24.

On the tension member 1t) there are also provided lower intermediate gusset plates 49 herein illustrated as being located approximately midway between the gusset plates on the compression member, the lower intermediate gusset plates being secured by bolts 50 to an upper leg l of the angle section comprising the tension member.

The diagonal bracing element 12 is secured by bolts 52 to the gusset plate 49 and by bolts 53 to the gusset plate 30. The diagonal bracing element 13 is secured by means of bolts 54 to the gusset plate 49 and by means of bolts 55 to the gusset plate 45 and particularly the lower portion 48 of the gusset plate 45. A somewhat similar diagonal bracing element 56 is attached in a corresponding fashion by bolts 57 to the other end of the lower portion 48 of the gusset plate 4S. From this point on the construction of the truss is a repetition of the portions illustrated in Figure l.

In order to support transverse joists 58 there are em ployed saddles 59 illustrated in some detail in Figure 5. Each saddle includes a foot 60 at the upper end of a leg 6l, the foot being spiked to the top of the plank over which it lies. A crossbar 62 connecting the lower ends of the leg provides a rest for the adjacent end of the joists 58.

By way of example the compression member 11 may have applied to the top thereof a roof deck 63 over the top of which is applied a waterproof rooting material 64. In' the event that a ceiling might be found desirable, wire lath 65, for example, could be applied to a lower leg 66 of the tension member and a suitable plaster ceiling 67 `applied to the wire lath following conventional construction.

By employing relatively short length planks, such as the planks 20 and 21, the cost of the wood portion of the truss may be held to a relatively low figure. Also by employing planks instead of solid Wood sections, the cost is similarly improved. Employing gusset plates which serve simultaneously to anchor the planks together, to`

anchor the sections one in abutting relationship with another, and also to attach the diagonal bracing, provides a compact multi-purpose joint which is inexpensive in cost of materials as well as simple to assemble Whether the assembly be at the point of fabrication or at the point of erection. In all respects standard structural shapes are employed in order to .hold material cost-s at a minimum. The combination of wood and steel to make the composite truss herein described furthermore makes possible the provision of a truss of relatively shallow depth for a span of considerable length and at a cost gure appreciably lower than trusses heretofore made available for similar purposes.

Further still and of particular merit is the fact that the upper compression member serving as a top chord member, being made of planks having considerable depth in the position shown, is capable of taking bending and compressive stresses. This enables the building of longer free spans and the omission of vertical bracing.

While I have herein shown and described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A composite beam structure adapted to provide a horizontal structural support comprising spaced anchorages, a lower continuous metal tension member extending from one anchorage to the other and secured to said anchorages, an upper wooden compression member supported at opposite ends by said anchorages, said compression member comprising a plurality of longitudinally disposed sections joined end to end in abutting relation and each section comprising a plurality of parallel planks mounted with the longest transverse dimension in vertical position, means joining said planks and connecting adjacent ends of said sections comprising a gusset plate extending into the ends of adjacent sections and positioned between planks of each section, said gusset plate having an exposed portion thereof extending below the planks, means extending through the planks of each section and the respective portion of the gusset plate, and diagonal bracing extending between and connected respectively to the tension member and the exposed portion of the gusset plates on the compression member.

2. A composite beam structure adapted to provide a horizontal structural support comprising horizontally spaced anchorages, a lower continuous metal tension member extending from one anchorage to the other and secured at opposite ends to said anchorages, an upper wooden compression member resting at opposite ends on said anchorages, said compression member being also secured in endwise relation to said anchorages, said compression member comprising a plurality of longitudinally disposed sections joined end to end in abutting relation and each section comprising a plurality of parallel planks mounted with the longest transverse dimension in vertical position, means joining said planks and connecting adjacent ends of said sections comprising a gusset plate extending into the ends of adjacent sections and positioned between planks of each section, said gusset plate having an exposed portion thereof extending below the planks, bolts extending through the planks of each section and the respective portion of the gusset plate, tension gusset plates on the tension member intermediate the gusset plates on the compression member and diagonal bracing extending between and connected respectively to the tension gusset plates and the exposed portion of the gusset plates on the compression member.

3. A composite beam structure adapted to provide a horizontal structural support free of columns intermediate opposite ends, said structure comprising horizontally spaced anchorages, a lower continuous metallic tension member of relatively small crosssectional area extending from one anchorage to the other and secured to said anchorages, an upper wooden compression member of relatively great cross-sectional area parallel to and spaced above the tension member and supported at opposite ends by said anchorages at a location above said tension member, said compression member comprising a plurality of longitudinally disposed sections joined end to end and eachr section comprising a plurality of parallel strips of uniform thickness mounted with the longest transverse dimension in Vertical position, means joining said strips and connecting adjacent ends of said sections comprising a gusset plate extending part way linto the ends of adjacent sections and positionedbetween strips of each section, transverse fastening means extending through the strips of each section and the respective portion of the gusset plate, and oppositely sloping diagonal bracing of cross-sectional area less than the area of the tension mem- `ber anchored at opposite ends respectively to the tension member and the gusset plates, said diagonal bracing lying in position extending across the space between the tension member and the gusset plates on the compression member and forming the sole means of joining said members together at the portions intermediate the ends.

References Cited in the file of this patent UNITED STATES PATENTS

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