Metal truss system

Abstract

The present invention is directed to a truss system comprising first and second chords and a number of joists in bolted connection to form a load bearing structure. The first and second chords extend longitudinally in parallel alignment to form the beams upon which a load will be spread across. The first and second diagonal members of a joist are aligned at approximately 45 degree angles to the first and second chord, and perpendicularly to each other, to maximize the load bearing capabilities of the truss system. By utilizing a utility support grid to couple a first truss to a second truss, the present invention can support a load spread over a greater area.

Description

RELATED APPLICATION

[0001] This application is a non-provisional application which claims the priority of prior Provisional application Ser. No. 60/242,964, entitled “TRUSS SYSTEM FOR UTILITY SUPPORT GRIDS, AND ASSOCIATED METHODS”, filed Oct. 23,2000, which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates generally to truss systems for load bearing applications, including commercial building support structures and more particularly, to bolted truss systems for load bearing applications.

[0004] 2. Description of the Related Art

[0005] In the erection of certain kinds of buildings, such as hangars and halls, there is a frequent need for steel trusses capable of spanning considerable distances or for supporting heavy loads. In many cases, it is desirable to design these steel trusses as generally rectangular frames including a pair of generally horizontally extending, longitudinal chords, an upper one and a lower one, which are interconnected at their respective ends by vertical posts and between their ends by a web of struts and ties (collectively, bar joists). In order to combine maximum strength with minimum weight in the completed truss, the various members thereof must be joined together with great care and accuracy in a pattern, in which they interact as efficiently as possible in a manner to give mutual support and thus prevent distortion of the truss under the expected load. Support grids are used at the ends to interconnect a first truss with one or more parallel trusses to create a truss system for support.

[0006] Typically, these trusses are prefabricated in a factory to a specified dimension. However, a problem in the prior art is that the bar joists used with building trusses are difficult to obtain. These trusses have a very long lead-time and impact building projects from a cost and time point of view. What is needed is a truss system that may be constructed with bolts, for ease of construction and placement, and to reduce costs. Additionally, it is desired to have a combined truss and support grid to form a truss system.

[0007] For background, the following patents are incorporated herein by reference: 4,637,193; 5,964,068; 4,637,193; 5,060,907; 3,994,111; 4,073,114; 4,277,923; 4,586,759; 4,934,886; 5,046,291; 5,060,907; 5,355,650; 5,363,513; 5,425,593; 6,073,414; 5,771,653; 4,836,436; 4,506,487; 5,964,068.

SUMMARY OF THE INVENTION

[0008] The principal objects and advantages of the present invention are to provide a truss system for structural support in load bearing applications; providing such a device that can be quickly assembled and properly positioned for use; providing such a device that is simple in construction, utilizing bolted connections and off-the-shelf metal framing in lieu of welded connections; providing such a device that is inexpensive in comparison to prior art designs; providing such a device that combines a truss system with a utility support grid; and providing such a device that is easily modified in selected dimensions to allow for optimized use in varying load bearing applications.

[0009] These objects and advantages are attained by the truss system of the present invention that comprises first and second chords in a parallel arrangement and coupled together at a set distance by a number of joists. The joists angularly subtend approximately 90 degrees in a first bolted connection with the second chord and a second bolted connection with the first chord. The first and second diagonal members of a joist are aligned at approximately 45 degree angles to the first and second chord. The configuration of the joists partition the first chord into (n) number of upper chord members and partition the second chord into (n-1) number of lower chord members. A support grid couples a first truss to a second truss with a cross configuration of framing members.

[0010] The uses of the invention are typically in construction of commercial buildings, including new building constructions or the retrofit of existing buildings as a secondary structural support system. The invention may also be used in retrofitting a facility where the existing structure will not support the loads imposed to it. In one example, existing structures are sometimes inadequate when they must incorporate cable trays and overhead utility support grids. The invention may further be used as a secondary support system, without utility grids, or particularly when bar joists are not available.

[0011] The truss system of the invention can be constructed on the job site and in a manner that is faster than the prior art. In one aspect of the invention, the truss system also incorporates the utility grid as a part of the truss system. Preferably, all trusses use off-the-shelf metal framing. The truss system of the invention also preferably uses bolted connections, from chord to web, in lieu of welded connections. The invention may have welded joints, but preferably does not incorporate welded connections.

[0012] Other advantages and components of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, which constitute a part of this specification and wherein are set forth exemplary embodiments of the present invention to illustrate various objects and features thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is a side elevational view of a truss system in accordance with the present invention;

[0014] FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 showing the support grids between a series of trusses of the present invention;

[0015] FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1 showing the support grids between a series of trusses of the present invention and connections to the truss system; and

[0016] FIG. 4 is a partial side elevational view of the truss system of the present invention showing the chords, the diagonal members of a joist, and the bolted connections for securing the elements together.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Referring now to the drawings, FIGS. 1 and 2 show a truss system 5 in accordance with the present invention. The truss system 5 comprises at least one truss 10 having a first chord 11 and second chord 12 rigidly coupled together by joists 13, and a support grid that couples adjacent trusses together.

[0018] The first chord 11 and second chord 12 are in substantially parallel alignment, extending lengthwise transversely in the horizontal plane. The first chord 11 is located vertically above the second chord 12 and is separated therefrom by a chord separation distance, indicated generally at A on FIG. 1. Both chords 11 and 12 are comprised of framing members that are elongate in nature and have upper and lower channel sections separated by a horizontally aligned web, as shown in FIGS. 2 and 3. However, any design known in the art to provide structural support for load bearing applications, such as I-beams, solid rods and closed channels, may be used as structural members. Chords 11 and 12 are also constructed and arranged to be of a sufficient size and material for supporting the loading estimates of the truss system 10. Depending on the length of the truss system 10 desired, the chords 11 and 12 may be formed from spliced framing members aligned lengthwise and rigidly connected together by one or more welded connections 29.

[0019] A plurality of joists 13 rigidly couple the first chord 11 to the second chord 12, thereby fixing the chord separation distance A. Such joists 13 are adjacent to each other and collectively span approximately the length of the first chord 11. Joint 13 comprises first diagonal member 14 and a second diagonal member 15. Diagonal members 14 and 15 are constructed of elongate framing members from any design known in the art to provide sufficient structural support for load bearing applications, such as I-beams, tubular beams, solid rods, and open channels. Also, such members are constructed to be of a sufficient size and material for distributing loads among the structural elements of the truss system 10, and preferably have a tube-shaped girth of approximately 1{fraction (3/4 )} inches.

[0020] The first diagonal member 14 has upper and lower ends 25 and 26, respectively, and the second diagonal member 15 has upper and lower ends 27 and 28, respectively. As shown in FIG. 4, the upper ends 25 and 27 of a joist 13 are coupled together and to the first chord 11 by a second bolted connection 16. Adjacent joists 13 are coupled together at lower ends 26 and 28 and coupled to the second chord 12 by a first bolted connection 17, as shown in FIG. 1. Both first and second bolted connections 17 and 16 are comprised of U-shaped joint brackets 22 connected to the first and second chords 11 and 12, respectively, and to joists 13 by means of a plurality of bolts. The bolted connections 16 and 17 are sized and configured to provide sufficient structural support for transferring forces between the chords and the joists in a load bearing application.

[0021] FIG. 4 shows the U-shaped joint bracket 22 having a base 30 and flanges 31 extending from the base. The base 30 has at least one hole for receiving a bolt to connect the joint bracket 22 of the second connection 16 to a bottom face 32 of the first chord 11 and to connect the joint bracket 22 of the first connection 17 to a top face 33 of the second chord 12. At least two holes also extends perpendicularly through both flanges 31, each receiving a bolt for connecting the joint bracket 22 to either the first or second diagonal members 14 and 15. Preferably, the joint bracket 22 is constructed and arranged with a size of approximately 20 inches in length, 4 inches in height from the base edge 30 up the flange 31, and 1¾ inches thick across the flanges 31.

[0022] Both diagonal members 14 and 15 of a joist 13 are aligned at approximately a 45 degree angle in the vertical plane to the first and second chords 11 and 12 and aligned approximately 90 degrees or perpendicularly from each other. This first diagonal member 14 has a negative slope and the second diagonal member 15 has a positive slope in the vertical plane. Both diagonal members 14 and 15 are connected. Such diagonal members 14 and 15 are constructed and configured such that the first diagonal member 14 angularly subtends approximately 90 degrees with the second diagonal member 15 by means of the second bolted connection 16. Additionally, the first diagonal member 14 of a joist 13 angularly subtends approximately 90 degrees with the second diagonal member 15 of an adjacent joist 13 by means of the first bolted connection 17.

[0023] This configuration of the joists 13 partition the first chord 11 into (n) number of upper chord members 19 defined between two adjacent second bolted connections 16 and partition the second chord 12 into (n-1) number of lower chord members 18 defined between two adjacent first bolted connections 17. Due to these partitions, the first chord 11 is of a length that is approximately one upper chord member 19 greater than the second chord 12. The joists 13 are also constructed and arranged such that a substantially perpendicular line to the first and second chords 11 and 12 is formed between a centroid of each of the upper chord members 19 and first bolted connections 17, and between a centroid of each of the lower chord members 18 and second bolted connections 16.

[0024] Depending on the structural support application to which the truss system 10 is applied, an end support member 21 may be connected to each end of the first chord 11 through one or more vertically aligned bolts, as shown in FIG. 1. The end support member 21, in turn, is connected to another structural support through one or more horizontally aligned bolts. This allows the loads carried by the truss system 10 to be transferred to the surrounding structure. The end support member 21 is designed from any configuration known in the art to provide support to the end of a load carrying member, and preferably is a bent 90 degree angle configuration with a triangular face plate on one side.

[0025] As shown in FIGS. 2 and 3, a support grid 23 may be utilized to couple adjacent trusses together. The support grid 23 is rigidly connected to the second chord 12 and couples a first truss 34 with a second truss 35 in a horizontal, symmetrically opposed orientation. Metal framing members 24 in a cross configuration connects the second chord 12 of the first truss 34 with the first chord 11 of a second truss 35, and connects the first chord 11 of the first truss 34 with the second chord 12 of the second truss 35. The framing members 24 attach to the first chord 11 on the top face 37 and attach to the second chord 12 on the bottom face 36, as shown in FIG. 3. As shown in FIG. 1, the framing members 24 are horizontally aligned in the longitudinal plane of the truss system 10 with the first and second bolted connections 17 and 16 to maximize the load bearing capabilities of the present invention. The first bolted connections 17 of the first truss 34 and second truss 35 are spaced apart by the support grid 23 a chosen distance for the required stability and load supporting characteristics, and are preferably four to five feet apart. The framing members 24 are preferably constructed from 12 gauge steel and comprise a U-shaped channel with a girth of approximately 1⅝ inches by 3¼ to 4{fraction (7/18)} inches. However, it is the understanding that any design known in the art to provide structural support for load bearing applications, such as I-beams, solid rods, and closed channels, may be used as structural members.

[0026] The present invention may be used in a broad range of applications, such as a structural support for new buildings and as a secondary support system for the retrofit of existing buildings. The present invention may also utilize different components with similar structural and material characteristics to the present components. Further, the dimensions of the current components can be modified as appropriate to enable the present invention to support a desired load. Since certain changes may be made in the above systems and methods without departing from the scope of the present invention, it is intended that all matter contained in the above description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense.

Claims

1. A truss system, comprising:

a first rigid chord;

a second rigid chord substantially parallel to the first chord, the first chord and second chord being separated by a chord separation distance; and

a plurality of joists rigidly coupling the first chord to the second chord at a chord separation distance, each of the joists having a first diagonal member and a second diagonal member constructed and arranged such that

(a) the first diagonal member angularly subtends about 90 degrees with the second diagonal member in a first bolted connection with the second truss, and

(b) the first diagonal member of at least one joist angularly subtends about 90 degrees with the second diagonal member of an adjacent joist in a second bolted connection with the first truss.

2. A truss system of claim 1, wherein the joists comprise n joists constructed and arranged to (a) partition the first chord into n upper chord members, each of the upper chord members defined between a pair of second bolted connections, and (b) partition the second chord into (n-1) lower chord members, each of the lower chord members defined between a pair of first bolted connections.

3. A truss system of claim 2, wherein the joists are constructed and arranged such that a substantially perpendicular line to the first and second chords is formed between a centroid of each of the upper chord members and at least one first bolted connection.

4. A truss system of claim 2, wherein the joists are constructed and arranged such that a substantially perpendicular line to the first and second chords is formed between a centroid of each of the lower chord members and at least one second bolted connection.

5. A truss system of claim 2, wherein the first chord is longer than the second chord by approximately one upper chord member.

6. A truss system of claim 1, wherein the first bolted connection comprises a first joint bracket, and further comprising (a) at least one bolt between the first diagonal member and the first joint bracket, (b) at least one bolt between the second diagonal member and the first joint bracket, and (c) at least one bolt between the first joint bracket and the second chord.

7. A truss system of claim 1, wherein the second bolted connection comprises a second joint bracket, and further comprising (a) at least one bolt between the first diagonal member and the second joint bracket, (b) at least one bolt between the second diagonal member and the second joint bracket, and (c) at least one bolt between the second joint bracket and the first chord.

8. A truss system of claim 1, wherein the first chord comprises one or more welded connections.

9. A truss system of claim 1, wherein the second chord comprises one or more welded connections.

10. A truss system of claim 1, wherein at least one of the first chord or second chords comprise material constructed and arranged with a girth of approximately 1⅝″ wide by 3¼″.

11. A truss system of claim 1, wherein at least one of the first chord or second chords comprise material constructed and arranged with a U-shaped girth of approximately 1⅝″ wide by 4⅞″.

12. A truss system of claim 1, wherein the first and second chords are constructed and arranged with material and girth size in accord with loading estimates for the truss system.

13. A truss system of claim 1, wherein at least one of the first or second diagonal members comprise material constructed and arranged with a tube-shaped girth of approximately 1¾″.

14. A truss system of claim 1, wherein at least one of the first or second diagonal members comprise material constructed and arranged with U-shaped girth of approximately 1⅝″ by 1¾″.

15. A truss system of claim 14, wherein at least one of the first and second bolted connections comprise one or more U-shaped fittings.

16. A truss system of claim 15, wherein the U-shaped fittings are constructed and arranged with a size of approximately 4″ by 20″ by 1¾″.

17. A truss system of claim 16, wherein each of the U-shaped fittings are separated by approximately four feet along the second chord.

18. A truss system of claim 1, further comprises one or more utility support grids formed of metal framing rigidly coupled to the second chord.

19. A truss system of claim 18, wherein the first bolted connection couples to the second chord at a first side of the second chord, and wherein the metal framing is constructed and arranged to couple to a second side of the second chord, and substantially adjacent to at least two of the second bolted connections.

20. A truss system of claim 18, wherein the second bolted connections are spaced at approximately four feet from one another, wherein the utility support grids comprises a four foot grid.

21. A truss system of claim 18, wherein the second bolted connections are spaced at approximately five feet from one another, wherein the utility support grids comprise a five foot grid.

22. A truss system of claim 18, wherein the metal framing comprises a U-shaped channel with a girth of approximately 1⅝″ by 3¼″.

23. A truss system of claim 18, wherein the metal framing comprises a U-shaped channel with a girth of approximately 1⅝″ by 4⅞″.

24. A truss system of claim 18, wherein the metal framing comprises 12 gauge steel.

25. A truss system of claim 1 or 18, wherein each of the chords and metal framing are constructed and arranged to meet a 40psf design load.