US3845594A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steel joist or composite steel and concrete construction
Assignee: Hambro Structural Systems Ltd
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Filing: 1972-01-25
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Granted: 1974-11-05
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Expires: 1992-01-25
Abstract
Abstract A steel joist formwork and a composite steel and concrete floor structure provided with a top chord, a bottom chord and a web joining the top and bottom chords with the top chord being serpentine shaped like an S or Z and including top and bottom, generally horizontal portions and an intermediate portion integrally connecting opposite edges of the top and bottom portions with the top and intermediate portions substantially being adapted to be embedded in the concrete floor to cause the floor and steel joists to act structurally as a composite beam. Either the web or a leg depends vertically from the free end of the bottom portion of the top chord, and the web joining the top and bottom chords is substantially solid or is, an open web formed of a zig-zag bar member. There is also disclosed a building system and erecting method utilizing steel joists spaced apart by spanner bars which also support rigid panels which act as formwork for the pouring of concrete. The spanner bars and the joists are so arranged to cooperate that the spanner bars may be removed together with the rigid panels after the concrete has been poured, and the spanner bars, the rigid panels and if desired the steel joists may be reused for formwork for additional poured concrete construction. Alternatively the joists may be left in place either with the top chords embedded in the poured concrete to provide a composite action, or merely supporting the concrete slab in the conventional fashion. A novel cold rolled sheet steel joist may be advantageously used to form a particularly economical composite system. This steel joist is shaped in an I-beam configuration with an upper top chord bent to have the appearance of the letter Z in cross-section for bonding with the concrete floor.
Inventors
- 👤 E Butts
- 👤 J Hall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:32
CPC Classifications
E; E04; E04G; E04G17/00; E04G17/18; E04B; E04B5/00; E04B5/16; E04B5/17; E04B5/23; E04B5/29; E04B5/32; E04C; E04C3/00; E04C3/02; E04C3/04; E04C3/06; E04C3/07; E04C3/08; E04C3/09; E04G11/00; E04G11/36; E04G11/40; E04G11/42; E04G11/48; E04G11/50; E04G17/14; E04C2003/0404; E04C2003/0408; E04C2003/0413; E04C2003/0421; E04C2003/0426; E04C2003/043; E04C2003/0434; E04C2003/0439; E04C2003/0443; E04C2003/0452; E04C2003/0486; E04C2003/0491
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
136 words
In a steel joist having top and bottom steel chords vertically spaced by a joining web, the improvement in said top chord comprising: a flat top element having two legs integrally extending downwardly from its opposite sides, each said leg having a first portion extending downwardly and the inwardly to form a ledge and a second portion extending from said ledge downwardly and being turned outwardly and upwardly again to form a channel for receiving notched spanner bars, wherein said upward turn of said channels is notched at spaced horizontal positions for aiding in the insertion and removal of said notched spanner bars, and wherein there are right angle pieces secured to the upper apices of said web with their arms being uppermost and extending horizontally outwardly from said apices and resting on said ledges respectively.
Claim 2
Dependent Claim
136 words
In a steel joist having top and bottom steel chords vertically spaced by a joining web, the improvement in said top chord comprising: a flat top element having two legs integrally extending downwardly from its opposite sides, each said leg having a first portion extending downwardly and the inwardly to form a ledge and a second portion extending from said ledge downwardly and being turned outwardly and upwardly again to form a channel for receiving notched spanner bars, wherein said upward turn of said channels is notched at spaced horizontal positions for aiding in the insertion and removal of said notched spanner bars, and wherein there are right angle pieces secured to the upper apices of said web with their arms being uppermost and extending horizontally outwardly from said apices and resting on said ledges respectively.
Claim 3
Dependent Claim
170 words
An elongated cold rolled sheet steel joist for use in a composite steel and concrete floor system having a bottom chord, a web, and a top chord rolled from a single strip of sheet steel, said bottom chord being generally centered beneath said web and having a generally flat bottomed box shape in cross section, said web being substantially flat and provided with a plurality of openings longitudinally thereof to receive spanner bars for supporting concrete pouring panels, said top chord having substantially the shape of the letter S or Z in crosssection and including integral top, oblique and lower portions the latter of which has an underside that flatwise extends transversely a substantial horizontal distance to hold down an edge of said concrete pouring panels against said spanner bars, the said top chord shape being effective to increase the shearing resistance between the top chord and concrete floor when poured on said panels over said top chord and to increase the load transfer from said floor to said joists.
Claim 4
Dependent Claim
170 words
An elongated cold rolled sheet steel joist for use in a composite steel and concrete floor system having a bottom chord, a web, and a top chord rolled from a single strip of sheet steel, said bottom chord being generally centered beneath said web and having a generally flat bottomed box shape in cross section, said web being substantially flat and provided with a plurality of openings longitudinally thereof to receive spanner bars for supporting concrete pouring panels, said top chord having substantially the shape of the letter S or Z in crosssection and including integral top, oblique and lower portions the latter of which has an underside that flatwise extends transversely a substantial horizontal distance to hold down an edge of said concrete pouring panels against said spanner bars, the said top chord shape being effective to increase the shearing resistance between the top chord and concrete floor when poured on said panels over said top chord and to increase the load transfer from said floor to said joists.
Claim 5
Dependent Claim
36 words
A cold rolled sheet steel joist as claimed in claim 2 with a plurality of horizontally elongated openings located at intervals in the vertical flange to support spanner bars between the cold rolled sheet steel joists.
Claim 6
Dependent Claim
223 words
A steel joist having a top chord; a bottom chord; web means joining and vertically separating the top chord and the bottom chord; said top chord including: a top flange generally perpendicular in transverse cross section to said web, and spaced therefrom, a lower flange generally parallel to said top flange with one of the lower flange edges being a substantial horizongal transverse distance from the other edge oF said lower flange, and the underside of said flange being substantially flat a distance sufficient to hold down an edge of a concrete pouring form panel supported by spanner bars, and an intermediate flange connecting said top flange to said lower flange, said intermediate flange extending obliquely between the top and lower flanges to connect one edge of the top flange to the said other edge of the lower flange to increase the shearing resistance between said top chord and a concrete floor poured onto said panel over said top chord and to increase the transfer of load from said concrete floor to said joists; the top chord further including: a flange depending vertically from the said one edge of the lower flange thereof and having at least two notch means therethrough for receiving respective ends of said spanner bars, said depending flange being connected on one of its sides to said web means.
Claim 7
Dependent Claim
223 words
A steel joist having a top chord; a bottom chord; web means joining and vertically separating the top chord and the bottom chord; said top chord including: a top flange generally perpendicular in transverse cross section to said web, and spaced therefrom, a lower flange generally parallel to said top flange with one of the lower flange edges being a substantial horizongal transverse distance from the other edge oF said lower flange, and the underside of said flange being substantially flat a distance sufficient to hold down an edge of a concrete pouring form panel supported by spanner bars, and an intermediate flange connecting said top flange to said lower flange, said intermediate flange extending obliquely between the top and lower flanges to connect one edge of the top flange to the said other edge of the lower flange to increase the shearing resistance between said top chord and a concrete floor poured onto said panel over said top chord and to increase the transfer of load from said concrete floor to said joists; the top chord further including: a flange depending vertically from the said one edge of the lower flange thereof and having at least two notch means therethrough for receiving respective ends of said spanner bars, said depending flange being connected on one of its sides to said web means.
Claim 8
Dependent Claim
63 words
A steel joist as in claim 4 wherein the said vertically depending flange, continguously with each notch means therethrough, includes a respective prescored portion which may be knocked out after a concrete slab has been poured upon the top chord of the steel joist, to permit disconnection of the concrete form spanner bar from the steel joist after the concrete slab has set.
Claim 9
Dependent Claim
23 words
The steel joist of claim 4 wherein the top chord, including the vertically depending flange, is integrally formed of cold rolled sheet steel.
Claim 10
Dependent Claim
265 words
A steel joist for use in a composite steel and concrete floor structure constructed by using spanner bars between adjacent separated parallel joists with the space between joints being substantially the width of a concrete pouring form panel, said joist comprising: a top chord, a bottom chord, and web means joining and vertically separating said top chord and said bottom chord, said top chord having a transverse cross section including a substantially S or Z shaped part having generally horizontally disposed upper and lower portions and an intermediate portion angling between opposite edges of said upper and lower portions with said lower portion being substantially flat on its underside for a distance sufficient to hold down one edge of said panel on top of said spanner bars and a vertically extending flange connected to the edge of said lower portion of said top chord which is not connected to said intermediate portion and extending in the direction of and connected to said web, said vertically extending flange having a plurality of openings to support said spanner bars, the defined shape of said shaped part of said top chord being effective to increase the shearing resistance between said top chord and concrete floor and to increase the transfer of load from the concrete floor to said joist with the strength of said floor structure being increased by composite action between said floor and joinst which act structurally as a composite beam when at least said upper and substantially all of said intermediate portion but not said vertically extending flange are completely embedded in said concrete floor.
Claim 11
Dependent Claim
265 words
A steel joist for use in a composite steel and concrete floor structure constructed by using spanner bars between adjacent separated parallel joists with the space between joints being substantially the width of a concrete pouring form panel, said joist comprising: a top chord, a bottom chord, and web means joining and vertically separating said top chord and said bottom chord, said top chord having a transverse cross section including a substantially S or Z shaped part having generally horizontally disposed upper and lower portions and an intermediate portion angling between opposite edges of said upper and lower portions with said lower portion being substantially flat on its underside for a distance sufficient to hold down one edge of said panel on top of said spanner bars and a vertically extending flange connected to the edge of said lower portion of said top chord which is not connected to said intermediate portion and extending in the direction of and connected to said web, said vertically extending flange having a plurality of openings to support said spanner bars, the defined shape of said shaped part of said top chord being effective to increase the shearing resistance between said top chord and concrete floor and to increase the transfer of load from the concrete floor to said joist with the strength of said floor structure being increased by composite action between said floor and joinst which act structurally as a composite beam when at least said upper and substantially all of said intermediate portion but not said vertically extending flange are completely embedded in said concrete floor.
Claim 12
Dependent Claim
16 words
A steel joist as in claim 7 wherein said top chord is formed from steel sheet.
Claim 13
Dependent Claim
19 words
A steel joist as in claim 7 wherein said top chord is rolled from a single piece of steel.
Claim 14
Dependent Claim
21 words
A steel joist as in claim 7 wherein said upper, intermediate and lower portions are integrally formed of cold rolled steel.
Claim 15
Dependent Claim
25 words
A steel joist as in claim 7 wherein said top and bottom chords and web means are integrally formed of a single piece of steel.
Claim 16
Dependent Claim
41 words
A steel joist as in claim 1 wherein said web means includes a serpentine shaped bar web having its upper apices welded to one side of said top chord vertically extending flange and its lower apices welded to said lower chord.
Claim 17
Dependent Claim
130 words
In a steel joist having top and bottom chords spaced by a joining web, the improvement comprising said top chord being constructed from a single piece of steel and having a transverse cross section including a substantially S or Z shaped paRt having integral top, oblique and lower portions with the lower portion extending from the lower end of the oblique portion a substantial distance horizontally in transverse cross section to the outer end of the lower portion with the underside of said lower portion being substantially flat to hold down an edge of concrete pouring form panels supported by spanner bars, and a downwardly extending flange integrally depending from the said outer end of said shaped part, said flange having a plurality of openings to support said spanner bars.
Claim 18
Dependent Claim
130 words
In a steel joist having top and bottom chords spaced by a joining web, the improvement comprising said top chord being constructed from a single piece of steel and having a transverse cross section including a substantially S or Z shaped paRt having integral top, oblique and lower portions with the lower portion extending from the lower end of the oblique portion a substantial distance horizontally in transverse cross section to the outer end of the lower portion with the underside of said lower portion being substantially flat to hold down an edge of concrete pouring form panels supported by spanner bars, and a downwardly extending flange integrally depending from the said outer end of said shaped part, said flange having a plurality of openings to support said spanner bars.
Claim 19
Dependent Claim
13 words
The improvement of claim 13 including a knock out adjacent each said opening.
Claim 20
Dependent Claim
45 words
A steel joist including the said top chord of claim 13 in combination with said bottom chord and said joining web, wherein said web comprises steel means including said downwardly extending flange for connecting said outer end of said shaped part to said bottom chord.
Claim 21
Dependent Claim
16 words
A joist as in claim 15 wherein said top chord contains only one said shaped part.
Claim 22
Dependent Claim
41 words
A joist as in claim 15 wherein the said horizontal distance that the said underside of said top chord lower portion extends flatwise is at least as great as the greatest horizontal width of the transverse cross-section of said top chord.
Claim 23
Dependent Claim
16 words
A steel joist as in claim 15 wherein said flange openings include respective horizontally elongated apertures.
Claim 24
Dependent Claim
35 words
A steel joist as in claim 18 wherein one end of each of said elongated apertures has a vertical dimension greater than the other end thereof for assisting insertion and removal of said spanner bars.
Claim 25
Dependent Claim
18 words
A steel joist as in claim 19 wherein said apertures taper from said one end to the other.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |