US2514607A

US2514607A - Truss construction

Info

Publication number: US2514607A
Application number: US646173A
Authority: US
Inventors: William B Mclean
Original assignee: Dravo Corp
Current assignee: Dravo Corp
Priority date: 1946-02-07
Filing date: 1946-02-07
Publication date: 1950-07-11
Anticipated expiration: 1967-07-11

Description

y 1950 'w. B. MOLEAN 2,514,607

TRUSS CONSTRUCTION Filed Feb. 7, 1946 2 Sheets-Sheet l INVENTOR Patented July II, 1950 UNITED STATES PATENT OFFICE TRUSS CONSTRUCTION WilliamB. McLean, Coraopolis Heights, Pa., as-

signor toDravo Corporation,v Pittsburgh, Pa., a corporation of Pennsylvania Application February 7, 1946, Serial'No.26;16,173.

4-.Glaims.

1 This invention "relates to metal truss construction for use in bridges, buildings, and other structures where strong trusses or girders are required, and relates particularly to atruss hav- 7 direction; and theother flange extending laterally .in .the other direction.

' such a truss, the view .beingon a somewhat larger scale than Fig. 1;

.Fig. 3 is .a side elevation on a smaller-scale of a portion of the truss shown in either .Ffigs. 1 or 2;

Fig.4 is a, view-similar to Fig. 2, showing still another modification, particularlyinsofaras the construction of the bottom .chord is concerned; and

Fig. is a View similar to Fig. 3.01? stillanother .modification, differing from Figs. 1 and 2 vparticularly in respect to the construction of the top .chord.

Referring first to the construction shown in Fig. l, the truss comprises a top chord designated generally as 2, and formed of two structural'members of Z-shaped section, these being designated 5 and 4. Each of the members 3-and A has a web 5 which is Vertical, a .bottom'flange 6 which is turned laterally outwardly, and the top flange l, which is turned inwardly. The flanges 1 of the two sections are brought to- .gether into abutting relation and are-welded along the abutting edgesas indicated at'B.

welding can be effected in the fabrication of i This the truss by an automatic weldingmachine, such as the submerged arc type, which requires accessibility of the joint for clearance for the machine.

The" two Z-shaped sections thus joined together overhang the webs of thetwo .2 sections.

forman inverted U-shaped chord. with outwardly extending flangesfi. The flatplate 9 ispreferably welded to the top of this invertedU-shaped structure so astto cover both of the flanges I and The weld is made at each sidealongthe outside of the-vertical webs '5 of the sections as indicated at 5-8. Thesewelds can also be made by a welding machine of thetype suggested above, or. a riveted. constructionemplo-yedif desired.

The bottom chordoflthe trussis designated generally asyiil. It also-is comprised-of two 2 sections designated l3 and I l. .They 'are of like construction, having .thebottom lateral flanges lfi'thereof turned outwardly, having the webs l6 thereofvertical, and having the tonfianges I! turned inwardly into abutting relation and welded together alongthe sea-m it. The bottom platei-9 is preierablywelded to .the bottom surfaces of the outwardly turned flanges -i 5,-f0l'lll ing -a hollow box-like chord. The seam ltinay be welded by a welding machine, .and thewelding of plate [9 to the bottomrof the flanges It may be accomplished. by -a' welding machine. The weldsior sec-uring'the bottornsolate Ill-in place are at 23.

. G-ussetplates'Z lwarewelded: to the inner faces of the webs- 550i the upper sectionsii and- 4 and proiectdownwardly. Gusset plates-fl'ii-are-welded to theoutsides of the webs l6 of the lower 2 sections [3 and M and project upwardly. The lower chord is slightly narrower-thanthe ,upper chord soathat the gusset plates 2! on the inside :of the webs of the upper chord and thegusset plates-22 on the outside of the-webs of thelower chord are. in the same-vertical: -plane. Vertical webs :23, preferably consisting of rolled structural sections of uniformwidth -.such as: channels or'beams, have theirupper:ends-projecting between the upper gusset plates E i and their lower endsv projecting between the lower gusset plates 22. These vertical elements 23'. are-welded to thegusset plates. Also diagonal metal members 24 of like character have their upper :ends extendingbetween and-welded to the upper gusset plates zl and have their lower ends extending between and-welded to thelower gusset plates '22. These diagonal members 2 3. arewalso .cr uniform width.

The general appearance Ofzthe truss. is shown inFig. '3, in which it will be :seen "iereware raws-uccession of vertical and :diagonalumembers .connecting the upper and lower chords of=the truss. Although welding has been indicatedwas the :-preferred means for connectionbf the gussets and the various members comprising the truss, it is appreciated that riveting or other means for connection may be employed without departing from the scope of this invention.

The several gusset plates being positioned against the flat webs of the 2 sections can be easily welded in place, and by reason of the construction, easy access for welding is provided. The location of one pair of gussets on the outside of the webs of the sections constituting one of the chords, and on the inside of the webs of the sections constituting the other chord with the different widths of the two chords so that the gusset plates along the top and bottom chords are in alignment, enables the uprights and diagonals to be of uniform width and avoids any necessity for cutting away or mutilating in any manner the rolled sections constituting either the top or bottom chords. The construction of the chords with a solid top formed by abutting the internal flanges prevents water or dirt from falling into the chord. The joining together of the two top flanges of these Z sections eliminates any need for expensive lacing across the tops or bottoms of the chords. The bottom flanges of the chord turn outward, giving a large radius of gyration in the lateral direction, and a correspondingly high lateral stifiness. This is of particular value for trusses which overhang a supporting tower, as for example in ore bridges, because the bottom chord is in compression, and a large radius of gyration permits higher unit stresses.

The interior of the top chord is very accessible for welding, painting and inspection, and in some instances the bottom plate IQ of the lower chord may be omitted, or contain hand-holes, to render it likewise very accessible for the performance of these operations. The top plate 9 and bottom plate I!) desirably increase stiffness, especially at the top of the truss where the plate 9, rigidly built into the truss, provides laterally extending flanges. 7

As will be most clearly shown in Fig. 2, all of the 2 sections are of originally uniform dimensions, but the top flange I! of one of the lower 2 sections M has been cut away so as to secure a condition wherein the width of the lower chord is slightly less than that of the upper, this incidentally placing the weld [8 a little to one side of center.

In the construction shown in Fig. 4, the general arrangement is the same, but the 2 sections have flanges which are wider along one edge than the other. In the upper chord, the sections are turned so that the wider flanges turn inwardly and abut, while in the lower chord, the 2 sections are reversed with the narrower flanges turned inwardly and joined by a plate welded thereto. This enables all four 2 sections to be uniform, without cutting away any of the flanges, and still enables the width of the lower chord to be narrower than the top one.

In this figure, the two Z sections forming the upper chord are designated 25. They have wide inturned flanges 26 at the top, butted together and welded, and 21 is a top plate that may be welded on. The sections 25 have outwardly turned narrower flanges 2B. In the lower chord, the two 2 sections are 29. They are the same as 25, but are inverted with respect to 25, so that the narrower flanges 30 are at the top and turn inwardly and the wide flanges 3| are at the bottom and turn outwardly. The top flanges of the lower chord sections are connected by a plate 32 welded thereto, the Width of the inverted U-shaped chord so formed being narrower than the top chord, so that gusset plates 33 on the inner webs of the upper section are in the same plane as gusset plates 34 on the outside of the sections of the lower chords. The connecting members 35, either vertical or diagonal, are arranged and welded as in Figs. 1 to 3. There may be a bottom plate 36 welded to the bottom flanges 3| of the bottom chord sections 29.

The truss of Fig. 4 has all of the advantages of Figs. 1 to 3 in that all longitudinal welds may be done by an automatic welding machine; all gusset plates are flat and welded to flat surfaces, and the truss has the same structural advantages, and it is unnecessary to cut down the width of any flange.

In Fig. 5 the chords consist of the same type of U sections formed of oppositely faced Z members, and in this figure the chords are of identical width and the gusset plates are in the same plane, both the upper and lower ones being welded to the outsides of the webs. In this View th upper sections 10 have the in-turned flanges t! at the lower edges and the out-turned flanges 42 at the top. A cover plate 43 may close the top of the U section so formed, and add strength to the truss. The 2 sections of the bottom chord are reversed, to form an inverted U, with the Webs M vertical, the in-turned flanges 45 at the top, and the out-turned flanges 46 at the bottom. There may be a bottom plate 41. The gussets, in all cases marked 48, are welded to the flat outsides of the webs, and the connecting struts are designated 49. The abutting inturned flanges of the sections are of course welded as hereinbefore described.

The several modifications illustrate certain preferred embodiments of my invention, but the parts may be also formed in other ways. The essential features of my invention embody the formation of upper and lower chords of 2 sections providing outwardly and inwardly turned -fiangeS and form chords of flanged U or inverted U cross section. In all cases, cross lacing of sections is unnecessary, and the trusses have the advantage both from a manufacturing and a structural standpoint hereinbefore noted.

I claim:

1. A truss construction characterized by its upper and lower chords each being formed of a pair of opposed Z sections with the webs thereof parallel and the inwardly turned flanges thereof rigidly connected, and flat gusset plates connected to the flat webs of the several Zv sections, those on the top chord projecting down and those on the bottom chord extending up, the gusset plates and connecting members connected to the gusset plates of the upper and lower sections being in transversely arranged pairs with the distance transversely between all pairs of gusset plates being the same, the connecting members comprising structural sections connected to the faces of the gusset plates and of a width corresponding substantially to the transverse distance between the pairs of gusset plates, the gusset plates on one chord being on the inner faces of the webs of the Z sections and. the gusset plates on the webs of the other chord being on the outer faces of the webs, the latter chord being transversely narrower than the former sufllcient to keep the spacing between all pairs of gusset plates uniform.

2. A truss construction characterized by its upper and lower chords each being formed of a pair of opposed Z sections with the webs thereof parallel and the inwardly turned flanges thereof rigidly connected, and flat gusset plates con nected to the flat webs of the several 2 sections, those on the top chord projecting down and those on the bottom chord extending up, the gusset plates and connecting members connected to the gusset plates of the upper and lower sections being in transversely arranged pairs with the distance transversely between all pairs of gusset plates being the same, the connecting members comprising structural sections connected to the faces of the gusset plates and of a width corresponding substantially to the transverse distance between the pairs of gusset plates, the gusset plates on one chord being on the inner faces of the webs of the 2 sections and the gusset plates on the webs of the other chord being on the outer faces of the webs, the latter chord being transversely narrower than the former suflicient to keep the spacing between all pairs of gusset plates uniform, the 2 sections of both chords having the inwardly turned flanges at the top thereof.

3. A truss construction characterized by its upper and lower chords each being formed of a pair of opposed Z sections with the webs thereof parallel and the inwardly turned flanges thereof rigidly connected, flat gusset plates connected to the flat webs of the several Z sections, those on the top chord projecting down and those on the bottom chord extending up, the gusset plates and connecting members connected to the gusset plates of the upper and lower sections being in transversely arranged pairs with the distance transversely between all pairs of gusset plates being the same, the connecting members comprising structural sections connected to the faces of the gusset plates and of a width corresponding substantially to the transverse distance between the pairs of gusset plates, the gusset plates on one chord being on the inner faces of the webs of the Z sections and the gusset plates on the Webs of the other chord being on the outer faces of the webs, the latter chord being transversely narrower than the former sufficient to keep the spacing between all pairs of gusset plates uniform, the Z sections of both chords having the inwardly turned flanges at the top thereof, a reinforcing cover plate welded to the inwardly turned flanges of the top chord, and a cover plate welded to the bottom of the sections constituting the lower chord.

4. A truss construction characterized by its upper and lower chords each being formed of a pair of opposed 2 sections with the webs thereof parallel and the inwardly turned flanges thereof rigidly connected, and flat gusset plates connected to the flat webs of the several Z sections, those on the top chord projecting down and those on the bottom chord extending up, the gusset plates and connecting members connected to the gusset plates of the upper and lower sections being in transversely arranged pairs with the distance transversely between all pairs of gusset plates being the same, the connecting members comprising structural sections connected to the faces of the gusset plates and of a width corresponding substantially to the transverse distance between the pairs of gusset plates, the gusset plates on one chord being on the inner faces of the webs of the Z sections and the gusset plates on the webs of the other chord being on the outer faces of the webs, the latter chord being transversely narrower than the former sufficient to keep the spacing between all pairs of gusset plates uniform, the Z sections of the upper chord having the inwardly turned flanges thereof at the top edges thereof.

WILLIAM B. McLEAN.

REFERENCES CITED The following references are of record in th file of this patent:

UNITED STATES PATENTS Great Britain 1889