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Патент USA US3094823

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'June 25, 1963
VAN RENSSELAER P. SAXE
3,094,813
BAR JOIST
Filed April 7, 1961
INVENTOR
' ATTORNEY
United States Patent 0’
IC€
Patented June 25., 1963
2
1
plates, shims, saddles or the like that are built as hearing
ends on the bar joists between the top of the beam and
3,094,813
BAR JOIST
3,094,813
re
_
Van Rensselaer P. Saxe, 1701 St. Paul St., Baltimore, Md.
Filed Apr. 7, 1961, Ser. No. 101,453
1 Claim. (Cl. 50-406)
the joist bearing support and secure the top chord of the
bar joist directly to the beam, and, at the same time, pre
serve a safe hearing from an engineering standpoint and
save the vertical material otherwise contributing to more
costly construction, while also saving placing of forms
This invention relates to an improvement in bar joists
for concrete as an extra item of work material cost and
used in concrete and steel building construction.
time
required to install the concrete ?oor covering.
Bar joist is widely used in steel frame building con
Another object of the invention is to use corrugated
struction work as the support for floors placed between 10
steel beams which are a part of the basic structural steel
construction. After these bar joists are erected by placing
them on seats on the top of the beams, they are covered
by a heavy wire mesh laid on top of the joist and spanmng
between the joists. This is a close woven mesh on top of
which is placed a very dry concrete mix which is troweled
smooth to form the floor. Bar joists are also covered with
sheets of corrugated metal laid on top of and running
crosswise of the joist to act as forms on which to place
concrete of normal consistency which forms the ?oor over 20
the joist. This method of using sheets produces less waste‘
of concrete material which occurs due to the sag of wire
mesh when it is used. After the concrete ?oor has been
sheet metal as top chord of the joist so these sheets of
corrugated metal with the corrugations disposed parallel
to the web of the joist with the ends of the corrugated
sheet resting directly on the beams and welded thereto and
provide the least possible depth or projection above the
building beam while said sheets have slots punched in
them so that serpentine-bar web peaks may be secured in
slots above the top surface of the corrugated sheet to be
included in the slab, while the lower valley portion of the
web have rods or other shapes welded on opposite sides
thereof to provide the bottom chord. Because of the
added lateral stiffness imparted to the top chord by the
corrugated sheets, as compared with angles, for example,
the resistance to compressive forces is better distributed
put in place, then a plaster ceiling is usually put on the
bottom of the joists to hide them from view and give a 25 and the rods for the bottom chord are in relatively the
same tension. However, the corrugated sheets provide
‘good ?nished appearance to the rooms under the bar joist
better support for the concrete ?oor material and prevent
supported concrete ?oor.
the usual material waste incident to the use of mesh or
Because of the use of plates or seats attached to the bar
crosswise placed corrugated sheets.
joists as bearing ends between the joist ends and the
Moreover, the corrugated sheets having considerable
30
beams, the overall height of a building is increased. The
sti?ness in themselves, when placed with the corrugations
general e?fect of this greater height of the bar joist type
parallel to and acting as a compression chord for the bot
of building is to increase the material required for every
tom tension members can form a beam unit of any de
vertical type of material used to make a completed build
signed strength. In such a beam the top ?ange corrugated
ing. Items under this heading would be more brick wall
acts as a ?oor or form on which to place the con
‘work, more partition work, more vertical piping, more 35 sheet
crete ?oor so by the act of placing one of this type joist
steel columns, etc., all of which cumulative costs o?set
on top of the steel supporting beam, you have in the same
much of the saving made in using bar joists with struc
act provided a steel ?oor form on which to place the con
tural frame construction. In other words, while the ?at
crete forming the ?nished ?oor.
.
slab bar joist concrete ?oor job is estimated to cost less
V
A
further
object
is
to
provide
a
bar
joist
wherein
the
40
because it can be much more rapidly erected, as for ex
edges
of
the
corrugated
sheet
metal
at
either
side
of
the
ample, a one or two-story building or an apartment project
sinuous web provide support for additional strips of
where early rental dates are a ?rst consideration, neverthe
sheet metal to complete the span between joists.
less it is actually more expensive in the long run than it
With the above and other objects in view which will
should be because of the total cost of extra materials used
in multi-story buildings, though there are some offsets to 45 appear as the nature of the invention is better under
stood, the invention consists in the novel construction,
this height increase due to the fact that pipes, ventilating
combination, and arrangement of .parts, hereinafter more
and air conditioning ducts, etc., can be run through the
fully described, illustrated, and claimed.
bar joists above the ceiling and are thus hidden from view.
A preferred and practical embodiment of the invention
The bar joist type of constructionhas one principal
.type of competition, namely what is known as ?at slab 50 is shown in the accompanying drawings, in which:
FIGURE 1 is a diagrammatic vertical cross sectional
reinforced concrete ?oors using reinforced concrete col
view of a concrete ?oor supported on the bar joist of the
umns to support the concrete slabs. While this construc~
'tion is slow compared with bar joist, it is also of generally
higher dollar cost than the bar joist type of ?oor supported
on steel beams.
present invention.
FIGURE 2 is .a detail cross-sectional view taken on
the line 2-2 of FIGURE 1, illustrating the preferred
However, as an o?set to this greater 55
form of the invention wherein two bar joists are attached
structural cost, it has one advantage over bar joists in
to the same sheet.
that the'concrete ?at slab can be designed so that it pro
FIGURE 3 is an enlarged ‘fragmentary perspective
duces a ?oor of considerably less thickness than can be
view emphasizing that the corrugated sheet forming the
secured by the use of bar joists as presently made and
top chord of the bar joist rests directly upon the sup
sold. The net result of this difference in ?oor thickness, 60 porting
beam.
,
which may be from 5" to 8", is that in a ten-story build
‘FIGURE 4 illustrates .a modi?cation of the invention
ing a bar joist building will be 50” to 80” higher than the
wherein a single bar joist of FIGURES 2 and 3 may be
same building constructed with ?at slab concrete con
attached to a single sheet iandthe adjacent edges of the
struction.
sheets overlap.
,
.
Accordingly, one of the objects of this invention is to 65
Similar reference characters designate corresponding
provide a solution to the problem of reducing the height
parts throughout the several ?gures of the drawings.
of a building and consequently its cost by making bar
The usual ‘beams which support the bar joist are desig
joists in a manner to retain and augment its structural and
nated as A, while the prefabricated bar joist assembly of
economic features, while reducing the height of the top 70 the present invention is designated generally as B. This
chord of the joist above the plane of the supporting beams.
new bar joist assembly includes a shallow top chord C,
'In'that connection it is proposed to eliminate bearing
serpentine web W, and bottom chord C’.
3
3,094,813
Corrugated sheet as disclosed herein is to be under~
stood as conforming to its dictionary de?nition, namely,
sheet iron bent into ‘series of alternate ridges ‘and grooves
in parallel lines, and when resting directly on the building
beams provide lowapro?le bearing portions.
As indicated at the preface of this speci?cation, the
distinctive feature of the present invention resides in pro
viding a bar joist wherein the corrugated sheet forming
the top chord has its corrugations disposed at right
4
tion between the corrugated sheet 1 and the inverted U
shaped peaks 7—7 due to the stiffness of the ribs and
the arching effect caused by the corrugations of sheet 1
because of the effect of stress ‘at these points, 5 and 6,
is transferred through the corrugated sheet 1 without local
bending or distortion of the sheet at said points as would
be the case in the use of a ?at uncorrugated sheet.
The projection of the peaks 7 above the general plane
angles to the beam A and parallel to the web W as l0 of the corrugated strips 1 is suf?cient to enable the con
crete to key into the arches beneath the peaks 7 and also
clearly shown in FIGURE 3. Thus the corrugated
to cover the peak heads to a depth sufficient to provide
sheet forming the top chord of the bar joist rests directly
the ?oor slab: S of adequate depth so that this concrete
upon the upper surface of the beam A thereby eliminat
slab on hardening will become a permanent and integral
ing height increasing plates, shims, chairs, or similar ele
ments which have a tendency to increase the height of 15 part of the bar joist which supports the concrete until set.
The web W of the bar joist, formed by the sinuous
the ?oor in the general overall height of the building,
bar has its lower valleys 9 connected to rods 10' welded
and to ‘have the corrugated sheet metal top chord act as
to either side of the stock forming the sinuous web.
a form ‘for placing of concrete.
These bars 10 which form the bottom chord C’ of the bar
"Referring more in detail to the bar joist assembly, it
will be observed that the same includes strips of corru 20 joist may be of relatively light stock.
Suitable rods 11 may be laid transversely of the cor
gated sheet metal 1 whose end portions 2 may be directly
rugations and preferably within and welded to the arched
welded as at 3 to the top surface of the beam A. Only
portions 7 of the sinuous web, with their ends bent down
part of one sheet is shown in FIG. 3 as resting on top
and welded as at l12L to the top of the sheets 1. Thus,
of the beam, but it will be understood that the end of
another sheet may substantially abut with the adjacent 25 these rods will give additional stiffness to the corrugated
sheets constituting the top chord and at the same time,
end of the related sheet shown, and, the end of the last
after the concrete has been placed on thecorrugated
sheet referred to will also be welded to the beam top.
There is an accepted theory in the use of concrete
slabs or ?oor-s ‘built on a steel beam of any character
sheets or plates, said rods will help to provide a better
anchorage for the loops 7 where they project up into the
concrete slab and also provides additional strength for
that, if you can, by mechanical means, ?rmly attach the 30
the completed slab once the concrete has hardened.
concrete slab to the top ?ange of the steel beam, the
In the preferred form of the invention shown in FIG
quantity of steel required can be materially reduced in
URE 2, certain valuable advantages accrue. For eX~
the top ?ange of such beam as much as sixty percent,
ample, by using two truss elements or webs for a single
and, through this mechanical attachment, the concrete
corrugated sheet, it is possible to more fully utilize the
slab will take the stress that the beam top ?ange would
compression value of a standard sheet. Moreover, by
take if it were full size.
connecting spaced truss members to a single sheet, fab
Thus, by substantially ?ushly anchoring the top
rication at the mill is facilitated and units thus con
chords C to the beam and also locking the concrete slab
structed may be easily stacked and transported. By
thereto by a portion of the sinuous web of the bar joist,
providing a pair of web~truss elements inwardly of the
not only is a stronger and‘ more practical construction
edges of the single sheet, proper overlap of adjacent units
provided, but additional economies are effected in the
may be readily effected, and it will be safer for men and
quantity of metal used in the bar joist.
equipment to travel over the units assembled on a beam.
As has been described, this use of a corrugated sheet
It will, or" course, be understood that the invention is
top and which acts as a form for placing and acting as
a unit with its bottom chord, has su?icient strength to 45 not limited to the use of a single sheet with the pair of
web-truss elements as above described because, in FIG
support the dead weight due to placing concrete on its
URE 4 it is shown that the invention can be fully uti
corrugated sheet top chord. When this concrete placed
lized where the single sheet 1 has only a single web-truss
on the corrugated top chord sheet hardens, it adds
attached thereto. This arrangement aside from the fact
strength by acting as a part of the top chord attached to
the bottom chord through the sinuous members making 50 that it is less convenient to handle and stack does not
fully and economically utilize all of the compression
up the complete joist.
value of the corrugated sheet.
The hardened concrete slabs add additional strength
Regardless of the speci?c embodiment of the invention
to the joist to carry live and other loads which may be
as shown in FIGURES 2 and 4, it will be understood
placed on the concrete ?oor and the bottom chord ten
sion bars of the joist are designed to support this addi 55 that the sinuous web is welded to the corrugated sheets
and the latter are Welded to the tops of the beams while
tional live load as well as the original dead load due
the edges of the corrugated sheets of one uni-t will over
to placing of concrete on the corrugated sheet forming
the top chord.
lap those of another to provide a combined top chord
and complete slab form.
As will be seen from FIG. 2, the top chord C of the
bar joist comprises a single corrugated sheet 1 with two 60 Since the edges of the corrugated sheets are welded
to the top of the beam, and, likewise, the ends of the
sinuous webs W attached thereto. These sheets are pro—
peaks of the top chord C are welded to the beam, and
vided at appropriate intervals with suitable openings or
said peaks forming anchoring keys ‘for the concrete, it
slots 4 formed by subjecting the sheets to dies which
will now be seen that the ultimately formed concrete
punch all sides of the metal to one side of the sheet to
provide end ?anges 5 and side ?anges 6 to snugly receive 65 slab S is directly tied to and connected with the sup
an inverted U-shaped peak 7 of the web- W. In the case
porting beam A to accomplish the important engineering
requirement previously set forth.
of the truncated end 8 of peak 7, this will be welded to
I claim:
the top of beam A. Also, the top portions 7 of the
sinuous bar constituting the web-truss W of the bar joist
A prefabricated bar joist having low pro?le bearing
are welded to the ?anges 5 and 6 of the corrugated sheet 70 ends to rest on related supporting beams of a building,
forming the compression ?ange of the joist.
The punching of the openings 4 to form the ?anges 5
and 6, because of the shape of the corrugated sheet 1,
provides, when the U-shaped peaks 7—7 are welded to
said ?anges 5, 6, an unusually stiff and strong connec 75
comprising, in combination,
a top chord constituting the upper compression member
of the bar joist andcomprising at least one sheet of
corrugated metal continuous from end to end and
having the corrugations manifested in the form of
3,094,813
alternate ridges and grooves disposed parallel to the
side edges of the sheet and also exposed at the
ends of the sheet, whereby, said alternate ridges of
the corrugations are adapted to rest directly on the
building beams,
said corrugated sheet having slots with edge ?anges,
a serpentine Web member disposed in a plane parallel
to the corrugations and having peaks projecting
through the slots and Welded to said ?anges to pro
vide high resistance to bending lengthwise ‘of the 10
sheet,
cross rods passing through and welded to said peaks
of the serpentine web member projecting above the
1,073,542
1,746,201
Stewart ____________ __ Sept. 16,
Tashjian ______________ __ Feb. 4,
1913
1930
1,804,132
1,977,260
Tashjian ______________ __ May 5,
1931
1934
2,13 6,071
Braden ______________ __ Nov. 8,
|Fro-mson _____________ __ July 3,
2,558,946
2,577,581
2,924,310
corrugated sheet and ‘also welded at their ends to
the edges of the sheet to prevent de?ection thereof, 15
and a bottom tension chord member secured to the
bottom portions of the serpentine Web.
6
References Cited in the ?le of this patent
UNITED STATES PATENTS
Evers ______________ __ Sept. 11, 1917
Re. 14,352
Wilson ______________ __ Aug. 3, 1909
930,255
Birdsey _____________ __ Oct. 16,
Hammitt et a1. ________ .... Dec. 4,
Colbath ______________ __ Feb. 9,
1938
1951
1951
1960
FOREIGN PATENTS
1,011,602
Germany ____________ __ July 4,
1957
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