US3527007A

US3527007A - Steel joist connection and end connection therefor

Info

Publication number: US3527007A
Application number: US751930A
Authority: US
Inventors: Ira J Mcmanus
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-08-12
Filing date: 1968-08-12
Publication date: 1970-09-08
Anticipated expiration: 1987-09-08

Description

Sept. 8, 1970 1. J. M MANUS 3,527,007

STEEL JOIST CONNECTION AND END CONNECTION THEREFOR Filed Aug. 12, 1968 3 Sheets-Sheet 1 INVENTOR. a 17 0 McM/Q/UUS Sept. 8, 1970 I. J. M MANUS 5 9 STEEL JOIST CONNECTION AND END CONNECTION THEREFOR Filed Aug. 12, 1968 3 Sheets-Sheet 2 INVENTOR. #34 07 MH/UUS QTTOF/UEX p 3, 1970 J. MCMANUS 3,527,001

STEEL JOIST CONNECTION AND END CONNECTION THEREFOR Filed Aug. 12, 1968 s Shets-Sheet s INVENTOR. A4 14 d, Wk: M/ /VUS QTTOR/UE X United States Patent US. Cl. 52-327 9 Claims ABSTRACT OF THE DISCLOSURE A steel joist construction and the connection therefor wherein the joist is of open-web steel having upper and lower chord members interjoined by a zig-zag bar-web, and wherein an angular bed plate member has a vertical web portion welded against the outer end of the joist and a horizontal outwardly-extending web portion adapted to seat upon and be secured to a supporting girder. Vertically-extending shear plate and keying means is welded either against the top of the horizontal bed plate member web portion, or alternatively, directly to the beam or girder in the vicinity of where the bed plate member seats. An outer end portion of the top chord of the joist is sloped downwardly toward the bottom chord to provide a greater thickness of concrete in a slab poured over the joist and supporting beam to enhance floor system rigidity while at the same time permitting more economical use 'of framework steel.

In my patent application, Ser. No. 546,648, filed May 2, 1966, and titled Steel Joist Connection, issued July 16, 1968 as Pat. No. 3,392,499, there is described improvements in the connections between the ends of openweb steel joists and the steel beams supporting them for superior steel and concrete floor construction. The present invention is directed to still further improvements over the end connection structures disclosed therein.

In my above-described patent, I disclose end connections for steel joists enabling the top chord of the joist to be placed substantially level with the top flange of the supporting girders or beams, permitting marginal portions of a concrete floor to be placed in bearing relation upon top portions of the girders or beams and thereby efiecting rigid interconnection of the floor slab with the girders or beams to act in unison therewith for increasing the rigidity of a floor or roof system. In the joist to beam or girder connections, the major parts thereof extend up into the concrete floor or roof to be encased thereby for both protection and increased rigidity. It is the primary object of the present invention to further improve the rigidity of interconnection between the steel joists and steel girders and beams, while at the same time simplifying and reducing the material and labor costs of such construction.

It is a more particular object to provide an end connection for open-web steel joists comprising a vertical shear plate member welded with respect to and extending upwardly of a top chord of a steel joist in spaced relation with the outer end thereof, and a horizontally-extending bed plate angle member having a horizontal web portion adapted to seat upon the top flange or other surface of a supporting framework girder or beam, and having a vertically-extending web portion secured against the outer ends of the steel joist upper and lower chord members.

Yet another object is to provide a steel joist construction and end connection therefor including key means secured to the outer end of the shear plate near or at the upper end thereof to enhance locking action to a concrete floor slab poured over the end connection.

Yet another object is to provide a steel joist construction and end connection therefor of the character described wherein the end portions of the upper chord of the joist are sloped downwardly toward the lower chord so that, upon assembly and construction of a building framework, the supporting beam or girder will be at a lower position with respect to the horizontal portions of the upper joist chord, thereby providing for increased slab thickness at marginal portions thereof over the supporting beam or girder.

Yet another object is to provide a steel joist construc tion and end connection comprising a horizontally-extending bed plate adapted to seat upon and to be connected to the top flange or other surface of a supporting framework, girder or beam, and having a vertically-ex tending web portion secured to the ends of the joist members. Keying between the concrete slab and the supporting girder or beam is by means of vertical plates, bars, bolts and the like secured directly to the top of the beam or girder and subsequently encased by the concrete.

Other objects, features and advantages of the invention will be apparent from the following description when read with reference to the accompanying drawings. In the drawings, wherein like reference numerals denote corresponding parts throughout the several views:

FIG. 1 is a side elevational view of a joist end connection embodying the invention shown connected to a support girder and further showing the use of form plates therewith for forming a concrete floor slab over a series of steel joists;

FIG. 2 is a top view of the joist end connection illustrated in FIG. 1, shown separately;

FIG. 3 is a side elevational view illustrating a modification of the joist end connection illustrated in FIGS. 1 and 2;

FIG. 4 illustrates, in side elevation, another modification of the joist end connection illustrated in FIGS. 1 and 2 wherein the top members of the joists are sloped downwardly at their outer ends to provide for a deeper section of concrete slab over the steel supporting beam;

FIG. 5 illustrates, in oblique view, a modification of the joist end connection illustrated in FIG. 3;

FIG. 6 illustrates, in oblique view, a modification of the joist end connection illustrated in FIG. 5;

FIG. 7 illustrates, in oblique view, still another modification of the joist end connection illustrated in FIG. 5;

FIG. 8 illustrates, in side elevation, a modification of the joist end connection illustrated in FIG. 4;

FIG. 9 illustrates, in side elevation, still another modification of the joist end connection embodying the invention; and

FIG. 10 is a vertical cross-sectional view taken along the line 10-10 of FIG. 9 in the direction of the arrow.

Referring now in detail to the drawings, and considering first the embodiment of the invention illustrated in FIGS. 1 and 2, 10 designates a typical open-web steel joist comprised of a pair of angle irons 11, 12 welded op posedly along the apices at one side of a zigzag bar-web 13 to form the top chord of the joist, and a pair of

steel rods

14, 15 welded opposedly along the apices at the other side of the bar-web 13 to form the bottom chord of the joist. The end connection embodying the invention comprises an elongated steel vertical shear plate 16, about 10 inches long, for example, one end of which is welded edgewise against the top of the joist top chord angle irons 11, 12 so that the other end of said shear plate extends outwardly of the joist to an extent somewhat greater than about one-half its length. Preferably, the thickness of the shear plate 16 is such as to just fit between the opposed surfaces of the top chord angle irons 11, 12 to facilitate welding thereat as is best illustrated at 17 in FIG. 2. Welded against the lower edge of the shear plate 16, as indicated at 18, is a bearing angle 19, having a horizontal web portion 19a and a downwardly-extending web or leg portion which abuts against the outer ends of the joist top chord angle irons 11, 12 and the bar-web 13, as indicated at 21. The upper corner at the outer end of the shear plate 16 is notched to receive a short, transversely-extend ing gey-bar 22, welded in place therein as indicated at 23. The key-bar 22 serves as additional means for keying the end connection in a concrete slab, as is hereinbelow more fully described.

It is to be understood that the desired end connection for joist 10 will be fabricated in the shop so that the assembly need merely be set in place between the supporting structure steel and welded. FIGS. 1 and 2 illustrate, by way of example, how the end connection at one end of the joist 10 is joined by welding, as indicated at 24, to the top flange of a girder 25.

The usual sheet metal form plates 26 placed on the erected joist form the bottom of a concrete slab 27 (see FIG. 1). In use of the end connection, the form plates 26 are placed to etxend over the top of the supporting girder as illustrated in FIG. 1 so that the slab 27, when poured, will have marginal portions bearing upon the supporting structures, and so that the concrete slab will at the same time encase the end connection.

FIG. 3 illustrates a modified form of the invention illustrated in FIGS. 1 and 2 described above, differing only in that the shear plate 16a is of shortened size and welded along is lower edge only to the top surface of the horizontal web portion 19a of the bearing angle 19, as indicated at 18a. Alternatively, the shear plate 16:: could be welded directly against the top flange of the girder near the outermost end of the web portion 1911.

FIG. 4 illustrates, in elevation, a modified form of joist end connection resulting in increased thickness of concrete slab over the connection at the supporting beam. To this end, the fabricated steel joist 10a differs from the joist 10 described above in connection with the embodiment of the invention illustarted in FIGS. 1 and 2 in that outer end portions of the top chord angle irons 11a, 12a are bent downwardly toward the bottom

chord steel rods

14, 15. With this construction, as will be apparent from an inspection of FIG. 4, the supporting beam or girder 25 will be in a lower position with respect to the upper surface of the slab, resulting in increased slab thickness at the marginal portions thereof over the said joist. This construction not only increases floor rigidity but also permits greater economies by permitting the use of smaller beam or girder cross-sectional sizes.

FIG. 5 illustrates, in oblique view, a modification of the joist end connection illustarted in FIG. 3 wherein a shear bar 161) of even shorter length is utilized, the up per end of which has welded thereto a transverse keybar 22a of substantaially the same width to present a T configuration. With this construction, the joist 10b could be either straight construction as illustrated in FIG. 1, for example, or of sloped outer end construction as illustrated at 10a in FIG. 4 and as described above. The lower end of the shear bar 16b can be welded either to the bed plate web portion 19a, as illustrated, or directly against the top flange of the girder 25.

FIG. 6 illustrates, in oblique view, a modification of the joist end connection illustrated in FIG. 5 wherein a headed cylindrical pin 16c is utilized as the shear and keying member, the head portion 16d of said pin member serving as the keying element. The lower end of cylindrical pin 160 will be welded either to the bed plate, as illustrated, or directly against the top flange of the girder 25.

FIG. 7 illustrates still another modification of the joist end connection illustrated in FIG. 5 wherein a pair of laterally-spaced bars 16c, 16 are utilized as sheer members, interjoined by welding at their upper ends by a transverse bar 16g serving as the keying element. Here again, the lower ends of the bars 16c, 16 can, alternatively, be welded directly against the top flange of the girder 25 instead of to the bed plate as illustrated.

FIG. 8 illustrates a modification of the joist end connection illustrated in FIGS. 1 and 2, differing therefrom in that a flat bearing plate 28 is used instead of a bearing angle 19, said bearing plate corresponding to the horizontal web portion 19a only of said bearing angle. Additionally, the outer end portion of the top chord of the joist structure is downwardly sloped, as in the embodiment illustrated in FIG. 4, to provide marginal portions of increased slab thickness over the supporting girder or beam.

FIGS. 9 and 10 illustrate still another modification of the inevntion, differing from the embodiment illustrated in FIG. 5 in that a rectangular reinforcing plate or bar 29 is welded against the outside of the downwardly-extending web portion 20 and between the top chord-angle iron members 11a 12a. In addition, a pair of diagonal bottom chord rods 13b, 13c are welded against the outside of the reinforcing plate or bar 29 at one end and, at their other ends, against opposite sides of the bar-web 13a and to the outer ends of the lower chord rods or

bars

14, 15.

While I have illustrated and described herein several forms in which my invention can conveniently be embodied in practice, it is to be understood that these forms are presented by way of example only and not in a limiting sense. While the steel joists herein illustrated and described are fabricated of welded-together steel angle iron and rod members, it is to be understood that other types of steel joists fabricated of steel members having other shapes could as well be used in combination with the end connection embodying this invention. The invention, in brief, includes all the forms and embodiments coming within the scope and spirit of the following claims.

What I claim is new and desire to secure by Letters Patent is:

1. In a steel joint construction and end connection therefor, the combination comprising a steel joist having an elongated upper chord, an elongated lower chord and web means interjoining said upper and lower chords in spaced relation, a horizontally-extending bed plate member secured to the upper end of said upper chord and projecting therefrom, said bed plate including an angle member having one flange secured to the end of said upper chord, a second flange projecting beyond the end of the upper chord in substantial coplanar relation with the upper surface of the upper chord, a shear member secured to said second flange and projecting upwardly therefrom, a keying member secured adjacent the upper edge of the shear member, a steel framework member, said second flange resting on the upper surface of said steel framework member and being secured thereto, and form means including plate means lying below the top surface of said shear member and resting upon said upper chord, and a concrete slab portion encasing said shear member engaging said form plate means and said keying member.

2. The combination as defined in claim 1 wherein said end portion of said joist upper chord is sloped downwardly in the direction of said lower chord to provide for a marginal concrete slab portion of increased thickness over said shear plate in a slab placed over said form means.

3. The combination as defined in claim 2 wherein said vertical shear member is in the form of a rectangular plate and wherein said keying means is in the form of a transverse bar welded within a recess provided in the top outer corner of said rectangular plate.

4. The combination as defined in claim 2 wherein said vertical shear member is in the form of a cylindrical headed pin, the head of which constitutes said keying means.

5. The combination as defined in claim 2 wherein said vertical shear member comprises a pair of transverselyspaced upright bar members and wherein said keying means comprises a horizontal bar secured to and between said upright bar members.

6. The combination as defined in claim 3 wherein said elongated upper chord comprises a pair of spaced, parallel angle-iron members, and a reinforcing plate welded edgewise against the outside of said downwardly-extending web portion of said bed plate member and between said upper chord angle-iron members.

7. The combination as defined in claim 6 including a reinforcing plate and a pair of spaced, parallel diagonal bars welded, at one end each, to the sides of said reinforcing plate and, at their other ends, to said lower chord.

8. The combination as defined in claim 3 wherein said rectangular plate extends inwardly over an outer end portion of said upper chord and is welded with respect thereto.

9. The combination as defined in claim 1 wherein said vertical shear member is welded to said bed plate.

References Cited UNITED STATES PATENTS 1,651,032 11/ 1927 Macomber 52--692 1,969,312 8/1934 Macomber 52692 2,055,701 9/1936 Palmer 52334 2,132,220 10/ 1938 Powers 52334 2,558,946 7/1951 Fromson 52334 3,008,556 11/1961 Hinze 52632 3,094,813 6/1963 Saxe 52336 3,307,304 3/ 1967 Klaasner 52334 3,362,121 1/1968 Weber 52334 3,392,499 7/ 1968 McManus 52334 FOREIGN PATENTS 1,285,747 1962 France.

828,255 1952 Germany.

HENRY C. SUTHERLAND, Primary Examiner US. Cl. X.R.