Note: Descriptions are shown in the official language in which they were submitted.
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The inven-tion relates to construction and
construction materials and more especially, it deals
with an improved reinforced concrete truss slab, and
a method of fabrication.
Relevant prior art is primarily in U.S. Patent
No. 3,334,458 and the steel forms or pans disclosed in
that patent which are the subject of a still earlier U.S.
Patent No. 2,602,323.
U.S. Patent No. 3,334,458 discloses a structural
member which is a reinforced concrete -truss slab which
embodies a lower reinforced concrete slab and an upper
slab with a network of passageways formed by way of steel
forms or pans integrated into the structural member. There
are columns of concrete extending between the upper rein-
forced slab and the lower reinforced slab with reinforcing
members or struts extending between the reinforcing means
in the lower slab and in the upper slab.
With respect to the method or technique of
fabricating the structural member of the prior art, the
lower slab is first poured with its reinforcing members
supported on supports which are known as chairs. The
forms Or pans arP positioned on the lower slab a~ter which
the upper slab is poured. When the lower slab is poured,
the connecting reinforcing members or s-truts are in
position to be embedded in the columns and in such position
they are in the way of the pouring process and thus impede
efficient fabrication. Also, this construction is an
impediment to ease of screeding after the slab is poured.
The present invention as described in detail
hereinafter is intended to overcome these def'iciencies
of the prior art and otherwise to realize objectives and
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provide advantages as described in de-tail hereinafter.
In accordance with the invention the improvement
in the st:ructural member resides in the reinforcing members
or struts which extend between the reinforcing means in
the lower concrete slab and that in the upper slab. In the
preferred exemplary form of the invention this reinforcing
strut member, which can be referred to as an insert, is
formed in sections including a lower section and upper
section, which is detachable from the lower section, the
sections preferably being threaded together. The lower
section includes a point which can be driven into the wooden
plywood slab or form on which the lower concrete slab is
poured. The inserts are positioned on centers corresponding
to the positions of the concrete columns between the upper
and lower slabs. The lower section is provided with two
diameters, forming an angular shoulder which, with a washer,
serves to provide a support for the reinforcing members
before the slab is poured, thus eliminating the use of "chairs"
to support the reinforcing members.
After completion of fabrication, that is pouring
and screeding of the lower slab, the upper sections of the
inserts are simply threaded into the lower sections, thus
being in position for becoming embedded in the upper slab,
the upper sections serving to support the reinforciny material
of the upper slab before pouring.
The invention further provides and makes possible
improvements, wit:h respect to the screeding after pouring
o~ the lower slab. For this purpose a modified form of insert
is provided, having a third section in the form of a straight
rod. AEter pouring of the lower slab, these third sections
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can be threaded into the ~irst sections of the insert,
-these sections being threaded in on 8' centers, for
example, to facilitate screeding. An angle bracket,
having a part with a hole in it can slip down over the rod
and then be set with a wingnut. This bracket forms a
holding bracket for a 2' ~ 4' and then a screed can be
simply slid along the tops of such 2' X 4's to screed the
concrete down to the desired level. After screeding and
insertion of the second sections of the reinforcing struts,
then the second sections of the modified struts~ having a
third section are coupled to the third sections and embedded
in the upper concrete slab.
In the light of the foregoing, the primary object
of the invention is to make available an improved composite
reinforced concrete truss member of the type having a lower
reinforced concrete slab and an upper reinforced concrete
slab, with a network of passageways formed in it and with
reinorcing struts extending between the reinforcing means
in the lower slab and in the upper slab~ wherein the said
connecting struts comprise insert means, having a lower
section and an upper section, which are separable so that
the lower slab can be poured and screeded without inter-
ference from the reinforcing struts.
A further object is to make available a reinforcing
strut in the form of a multi-part member having a bottom
section, which can be supported on formwork, typically a
wooden platform on which a concrete slab is poured and
which i5 arran~ed to support reinforcing ~laterial and to
which an upper section can be secured after the lower concrete
slab has been poured and screeded.
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A further object is to realize an improved
reinforcing strut member in the form of an insert as
described, wherein a third intermediate section is
provided adapted for supporting a screed holding
bracket to facilitate the screeding of the lower slab
of the composite member~
A further object is to realize the advant.age
of accurate assured placement of the steel in the lower
slab, with the assurPd vertical axis of the inserts.
Further objects and additional advantages of
the invention will become apparent from the following
detailed description and annexed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 i.s a partial cross-sectional view of
a preferred form of the reinforced structural member of
the invention;
Figure 2 is a sectional view taken along line 2-2
of Figure I;
Figure 3 is an enlarged sectional view of a part
of the structural member, illustrating the construction of
the lower section of one of the reinforcing inserts;
Figure 4 is an enlarged cross-sectional view
similar to that of Figure 3, further illustrating a complete
reinforcing insert strut extending between the lower slab
and the upper 9 lab;
Figure. 5 is an exploded view of a preferred form
oE insert;
Figure~ 6 (on the same card as Figure 1) is a
sectional view of a modified form of the bottom section of
an insert membex which has a threaded bore in the lower end
also;
~ igure 7 is a partial sectional view illustrating
utiliza-tion of the insert -to support a screed, a~d,
FicJure 8 is a par-tial sec-tional view of a modified
form of inser-t ~ormed in ~hree sections;
The following description includes as well the
best mode of prac-tice o~ the invention.
With respect to the prior U.S. Patents Nos. 2,602,323
and 3,334,~58 certain of the technolo~y defined in these
patents may be relevant and is accordingly omi-tted from this
description to avoid duplication.
Referring to the drawings, numeral 10 in Figures
1, 2 and 3 designates a preferred form of the improved rein-
forced structural member.
Numeral 12 in Figure 4 designates a preferred form
of the improved insert member, namely, the reinforcing strut
member that extends between the lower slab 16 and upper slab
22. The structural member 10 of Figures 1, 2 and 3 is similar
to that shown in Figures 9 - 11 of Patent No. 3,334,~58. The
forms q~ pans 23 for the structural member preferably would
correspond to that shown in ~igures 6 and 7 of the earlier
patent.
The diagonal shear reinforcing members, as shown in
the prior patent are replaced in the herein invention by
means of the reinforcing members r that ls, the lnserts as
shown in Figure ~.
A base slab 16 is shown which is poured firs-t,
pre~erclbly on a form or surface typically made of wood,
such as plywood or the like, as designated a-t 18. The lower
s:Lab 16 has reinforcincJ members embeddecl in it, as will be
clescribed.
The upper concrete slab 22 overlies the network
of forms or pans 23, which as stated correspond to those of
f' `~`` 5
the previous patents and which form -the interlockiny
passageways such as designated by the numeral 24. The
upper slab 22 forms the columns or pillars 26, which are
between adjacent forms 23 and which connect the upper
slab 22 and the lower slab 16.
The reinforcing struts in the form of the inserts
12, are positioned as shown to align with the columns or
pillars 26~
Each of the reinforcing struts 12, as shown in
Figure 4, is in the form of an insert, which includes a
bottom section 30. The lower part 32 of this section has
a larger diameter so as to provide a s~uare shoulder 34.
A pointed member 36 is loosely placed into a bore in the
lower end of the section 30, and can be driven into the
wooden platform 18 to support this section of the insert
12 during pouring of the slab 16.
The bottom section 30 of insert 12 has a threaded
bore 42. A washer 44 can fit down over the upper part of
section 30 abutting against the shoulder 34. A second
section 50 of the insert 12 includes a threaded part 51,
fastening in bore 42, and an upper angular part 52 which
comes into a position associated with the reinforcing members
embedded in the upper slab 22, as will be described. An end
cap 54 (Figure 3), having a threaded stem 55, can be threaded
into the bore ~2 in a position as shown in Figure 3 during
pouring of the lower slab, the height of the lower section
30 being such that cap 54 will be level with the upper
surface oE the lower slab 16 when poured. Preferably, caps
5~ will be formed with some Eorm of rotation inducing surfaces
or recesses of any known type, such as will not interfere with
screeding.
Reinforcing members 62 and 63 are embedded in the
lower slab 16, together with reinforcing mesh 60 usually in
two layers. Reinforcing members 64, 66 are embedded in the
upper slab 220 It will be observed that the angular part 52
of the second section 50 of insert 12 e~tends over the rein-
forcing member 66 of upper slab 22 as shown in Figure 1.
Normally the reinforcing member 66 is fastened to the angular
par~ 52 of the second section 50 to hold it in position before
pouring the upper slab.
The formwork or wooden surrace, such as plywood 18,
is positioned where the lower slab 16 is to be poured. Before
pouring, the inserts 12 are positioned on centers, as shown,
to be aligned with the concrete columns or pillars 26 formed
as part of the upper slab 22. Before pouring the concrete
for the lower slab, the reinforcing members 60 and 62 are sup-
ported on the washers 44, as shown. The end caps 54 are ins~rted
in position in the bores 42 of the lower sections 30 of the
inserts 12.
Typically, the reinforcing material includes the
reinforcing mesh material 60 as well as the members 62 and 63.
In the prior art it was customary to support the reinforcing
material from the plywood decking by pieces or members,
called chairs, made of plastic. When the concrete was
poured, these members would become embedded. The spacing
of such members would depend upon the thickness and weight
of the reinforcing material. In the herein invention, the
chairs ~re eliminated by use of the inserts, as described
in the foregoing. The reinforcing wire mesh screen 60 may
have mesh openings four inches on a side ~not shown), for
example, and it is supported by the inserts as described,
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positioned at a corner of the mesh, that is the first layer
of mesh. Then the second layer can be laid on top of the
first layer, with the intersecting wires at the diametrically
opposite part or position of the insert, so that the result
is that the insert cannot move around. Thus, it can be seen
that the upper and lower layers of mesh, positioned as des-
cribed, will lock the ins~rt members 12 in position, immovably.
This technique insures that the inserts will be straight up
and down, that is vertical, which is, of course, desirable
for purposes of threading in the reinforcing members.
The concrete is then poured for the lower slab.
Screeding can be done in a manner known in the prior art,
or in a preferred manner as described hereinafter.
It is significant that since the caps 54 at the
top ends of the lower sections 30 of the inserts are at
the same level as the top surface o~ the lower slab 16,
they are not in the way and they are not an impediment to
screeding. Minor adjustments in height may in some cases
be made, by adjusting caps 54 upwardly, to accommodate
minor variations in the thickness of the slab. In this
way openings are left in the lower slab giving access to
the bores 42.
After screeding, the caps 54 are removed and the
upper sections 50 of the reinforciny struts are then threaded
into the bores in the lower sections 30 so that they are in
a vertical position with their angular parts 52 in a position
as shown in Figures l and 3 and as previously described.
Pans or forms 23 are then located in place and
the reinforcincl members 66 are attached to portions 52 as
de5cribed.
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The upper slab 22 is -then poured producing a
structural member as shown in the figures with the columns
or pillar 26 of concrete formed in between the pans or
forms as already described with the reinforcing struts 50
embedded in the columns in a vertical position as shown.
The structural mer~er, as described, has all the
features, ad~antages and characteristics as described in
the prior Patent No. 3,334,458 in addition to having the
improvements as described herein.
Figure 6 shows a lower insert section 30' of a
modified form of insert. The section 30' has a threaded
bore 70 in its lower end. ~n end fitting 72 that can be
threaded into the bore 70.Fitting 72 includes a flange part
73, having extended point 74, which can be driven into the
formwork or wooden surface on which the lower slab 16 is
poured. When the slab 16 is completed and the formwork is
removed the fitting 72 can be removed and then the thxeaded
bore 70 provides means for supporting light fixtures, ceiling
structure, plumbing, air conditioning and the like. Pref-
erably, fittlng 72 will have suitable rotation inducing
surfaces of any known type, capable of permitting unthreading
for this purpose.
Figure 7 of the drawing shows utili~ation of the
inserts 12 for providing capability for facilitating
screeding~ ~fter pouring the lower slab 16, straight inter-
mediate rods or sections, as shown at 80, are threaded into
the lower sections 30 of the inserts on 8' centers. Figure
7 shows screeding supports such as angle brackets 88, which
have parts 90. Each part 90 has a hole in it where it can
fit over the sec-tion 80 and can slip down over the section 80
so as to be held by a wingnut 82. Wooden supports such as
2' X 4's designated by 94 can be supported on brackets 88,
as shown, and then a screed, as shown at 100, can be supported
on these 2' X 4's and slid over the lower slab for screeding.
The screed includes an upper member 102, having nailed to it
the screeding member 104 with a spacer member 103 in between.
After screeding, the section 80 can be removed and
the regular stirrups 50 can be put in position in all of the
inserts, as previously described.
Figure 8 shows a slightly modified arrangement,
wherein the sections 80 can be left in position after
screeding the lower slab. The upper slab is ~hen poured
and after pouring, the wet concrete is displaced sufficiently
to attach modified reinforcing stirrups as shown at 50' to
the sections 80, by way of attachment members or couplings,
such as shown at 108.
From the foregoing, those skilled in the art will
readily understand the nature o the invention, as well as
the manner of construction and fabrication of the slab, as
well as the techniques involved. The construction and the
techniques of fabrication as described in the foregoing,
represents the preferred form of practicing the invention.
Having described what is believed to be the best
mode by which the invention may be performed, i-t will be
seen that the invention may be particularly defined as
~ollows:
In an improved composite truss member, having a
horizontal base slab of concrete, which has reinforcing
me~ns extendiny through the slab, a web formation comprising
3n spaced orm members providing a network of spaces for allowing
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air circulation through the network of spaces for allowiny
air circulation through the network overlying said base
slab, an overlying layer of concrete on the web formation
and having spaced columns of concrete extending through the
web formation to said base slab, the base slab having rein-
forcing members embedded in the slab, the improvement
including the reinforcing members having member portions
extending through the said columns, the said member portions
being individually separable and including a first section
embedded in the base slab, each section terminating substan-
tially at the level of the base slab and a second section
detachably securable to the first section, whereby the base
slab can be poured without the second sections in place, so
as to not be in the way during pouring the overlying layer
forming a slab overlying the base slab.
The foregoing disclosure is illustrative of the
preerred form of the invention and is to be interpreted in
an illustrative, rather than a limiting sense, the invention
to be accorded the full scope of the claims app~nded hereto.
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