Note: Descriptions are shown in the official language in which they were submitted.
i~.21~;13
BACKGROUND OF IHE INVENIION:
Ihe present invention pertains to steel reinforcement used in c~ncrete
block construction, and more particularly to a device for positioning verti-
cal steel reinforcement bars precisely where they are designed to be loca-
ted, so that the full tensile strength of the steel bar is utilized, as intend-
ed by the engineer who de signs the wall.
Concrete blocks and mortar have relatively little t~nsile strength, and
it is therefore necessary to use st~L reinforcing bars to provide the necess-
`- ary tensile strength; some of the bars extending vertically through the cavi-
ties in the blocks, so as to anchor the blocks to the concrete footing; and
10 some extending horizontally along the mortar joints at various ~evels. Ihe
vertical bars are particularly important, as they provide most of the ten-
sile strength to prevent the wall from failing under horizontal pressure,
such as the pressure exerted by soil on one side of the wall. For most
economical design, the engineer locates the bar as far as possible from
'- the neutral axis of the wall toward the tension side of the wall, while still
allowing a certain minimum amount of space between the bar and the inner
.- surface of the block cavity to allow concrete grout to flow around the bar
so as to completely embed it. This is done by specifying a distance "d"
from the outer surface of the block on the compression side of the wall
;; 20 to the center of the vertical steel bar. Ihe larger the distance "d", the
smaller the required steel area. If the actual "d" is smaller than the de-
sign "d", then the actual stress on the steel will be greater than the cal-
culated stress, with the consequent potential for overstressing the steel.
In practice, it is difficult and, in fact, almost impossible to keep the
,
- vertical reinforcing bar at the precise distance "d" relative to the outer
surface of the blocks from the top of the wall to its bottom as the grout
is being poured. As a result, the bar may drift or bend away from the
inne r surface of the block toward the neutral axis of the wall, where the
-2- ~Ik
.',f ',
1~ 3
bar is subject to being overstressed. Io compensate for uncertainty as to
the actual disl;ance "d", dcsign engineers customarily use only 50% of the
tensile strength of the steel in their calculations if there is not to be con-
tinual inspection of the steel on the job. Ihis results in the use of oversize
steel bars. Even when oversize steel reinforcing bars are specified, there
;~ is SOme danger that the bars may b ecome displaced far enough from their
design location to make them relatively ineffective, resulting in overstress
in the masonry. Specifying oversize reinforcing bars is expensive, and adds
greatly to the cost of the wall.
, 1~ SUMMARY OF IHE INVENIION:
~'
' Ihe primary object of the present invention is to provide means for
......
~ positively locating vertical reinforcing bars at the precise position called
~.,
for in the specification, thereby assuring the design engineer that the bar
will remain at its intended location at all times, and its full tensile strength
will be utilized. Ihis object is achieved by means of continuous, ladder-like
; as semblies that are placed in the horizontal mortar joints of the wall at
specified levels as the wall is built, the said assembly being formed of
- two laterally spaced steel wires that are joined together at intervals by
., ,
, transverse wires, having downwardly projecting locator pins that engage
, ~ 20 the blocks to position the assembly in the desired location, while certain
,.. .
~, of the transverse wires have circular rings formed therein, through which
the vertical reinforcing bars are pas sed.
Among the advantageous features of this arrangement are:(l) it is easy~''
to use, and saves time and money; (2) no special skill is required~ Ihe
ladder is merely placed on the mortar joint, and locator pins position the
ladder in the correct position; (3) the vertical reinforcing bars are fixedly
held in the desired pocation and cannot move either longitudinally or trans-
versely with respect to the wall; (4) the added steel of the ladder reduces
the amount of steel reinforcement required; and (5) it allows the de sign
--3--
,
.
llZ~613
-, engineer to use the full allowable stress for the steel
reinforcement bar, as he can be confident that the bars
will remain at the exact position specified and will not
~ drift to a position where they would be subject to over-
; stressing.
In summary, therefore, the present invention
provides a fixture for use in masonry construction utiliz-
ing hollow blocks having two longitudinally spaced cavities
separated by a transverse web, wherein vertical reinforcing
1') bars must be precisely located within a cavity that is sub-
sequently filled with cement grout, the fixture comprising:
a horizontal supporting structure that is adapted to be placed
on the top surfaces of the blocXs at various levels of the
- masonry construction as the blocks are being laid, the
supporting structure consisting of a ladder-like unit formed
with laterally spaced, parallel wires that are connected to-
~ gether at intervals by cross-wires;
; the horizontal supporting structure having a plur-
ality of rings provided thereon at locations where the rein-
- 20 forcing bars are to be locatedr the! rings of the supporting
structures at different levels of the masonry construction
being vertically aligned with respect to one another so as to
receive the vertical reinforcing bars when the latter are
passed downwardly into the cavity and through the rings from
the top of the completed or partially completed construction;
; and
certain of the cross wires having cross pieces
attached thereto, the cross pieces terminating in downwardly
bent legs that are adapted to straddle the transverse webs
of the blocks.
..
Pg/~j~ - 4 -
1 .
: .
,
`~ L3
BRIEF D~SCRIPTION OF TIIE DR~WINGS:
Figure 1 i5 a perspective view of a course of
hollow concrete blocks, showing the device of the inyen-
tion placed on a mortar joint, and with one vertical rein-
forcing bar inserted through a ring in the device;
Figure 2 is an enlarged cross-sectional view taken
at 2~2 in Figure l;
Figure 3 is a fragmentary sectional view taken
at 3--3 in Figure l;
Figure 4 is a perspective view of a slightly differ-
ent form of the invention setting on a mortar joint of a
course of blocks, this embodiment being used where two verti-
cal reinforcing bars are arranged side-by-side, as when the
bottom courses of a wall are of extra wide blocks, while the
upper courses are of normal width blocks;
Figure 5 is a view showing an end view of a wall
constructed as described above;
Pg/~,' - 4A -
..
.i. , .
~;,
....
l~L~3
Figure 6 is a perspective view of a short lengttl of still another em-
bodiment of the invention;
Figure 7 i8 a perspective view of a square column formed of blocks,
or bricks, showing another form of the invention; and
Figure 8 is a perspective view of still another form of the invention,
for use in building a square column as shown in Figure 7.
DESCRIPIION OF IHE PREFERRED EMBODIMENI:
In Figures 1-3 of the drawings, the reference numeral 10 designates
a portion of a block wall, made up of a plur ality of conventional hollow
10 concrete blocks 12, which are mortared together by end mortar joints 14
and horizontal mortar joints 16. In the drawingsJ the exposed top surface
of the blocks is designated as a horizontal mortar joint, although no mor-
tar has been applied as yet. Each of the blocks 12 has two side-by-side
:~ cavities 18 formed therein, which are separated by a transverse web Z0.
Ihe device of the present invention is designated in its entirety by the
reference numeral 22, and is seen to be generally ladder-like in configur-
ation, being made of two laterally spaced, parallel wires 2~ and 26, which
are joined together at intervals by transverse wires 28 and 30. Ihe wire
is preferably about No. 8 gauge steel wire, although other gausges may be
20 used, depending upon the strength requirements. For a nominal 8-inch
block, which is actually 7-5/8 inches wide, wires 24, 26 would be spaced
6-1/8 inches apart, so that the wires each lie 3/4 inch from the outer
edge of the block, so that if the mortar joint is raked, the wires will not
be exposed. In the case of a 12-inch block, which is actually 11-5/8 inches
wide, wires 24, Z6 would be spaced 10-1/8 inches apart~ For blocks of
other width dimensions, the wires 24, 26 would be spaced apart 1 -1 /2
inches less than the actual width dimension.
Iransverse wires 28 are forr~ d with down~hardly projecting legs 32
near each end thereof, which converge siightly, as best shown in Fig~2
--5--
l~l.Z~6~3
Legs 32 may be formed by bending the wire, as illustrated in the drawing,
or by welding short lengtlls of wire to the crosspieces Z8. Ihe purpoHe of
the legs 32 is to ccnter the ladder-like wire fixture 22 in the middle of
the line of blocks 12, and to this end, the leg~ 32 are inserted down into
the cavity 18, where they engage the inner side wall surfaces of the blocks.
l~he ~downward taper, or convergance, of the legs 32 facilitates insertion
of the leg s down into the cavity, and when the device 22 is in place, the
upper ends of the legs make contact with the cavity surface of the block,
1 or lie very closely adjacent thereto, e. g. about 1/8-inch distance.
`~ 10 Clos~Lyadjacent one of the legs 32, the cross wire 28 is coiled into a
circular ring 34 having an inside diameter of approximately 3/4-inch, so
that a 318, 1/2, or 5/8-inch steel reinforcing bar 36 can be passed down
through the center of the ring. In some cases, as for free-standing walls,
it may be desirable to have the vertical steel reinforcing bars 36 centered
within the block cavity 18, in which case the ring 34 would be formed at
the midpoint of the wires 28.
Cross wires 30 have no circular rings, but instead are provided with
locaters 38, each consisting of a cross piece of wire 40 having a pair of
downwardly turned legs 42 that straddle the center web 20 of the block, s o
2 0 as to fixedly locate the ladder-like fixture 22 lengthwise along the wall.
Legs 42 also diverge downwardly to facilitate placing the legs down over
the web 20.
" .
S Ihe Uniform Building Code states that the vertical reinforcing bars 36
- shall not be spaced more than 48 inches on center, but may be any lesser
distance, such as 16, 24, 32 or 48 inches. Rings 34 may therefore be
spaced apart along the length of the ladder-like fixture 22, various incre-
ments of distance which would make it possible to space the vertical bars -
at 16, 24 32 or 48 inches on centers. Cross wires 30 with their locaters
; 38 would be spaced apart some multiple of the block length, so that the
.: .
13
legs 42 will always be positioned to straddle the center web of a respec-
tive block.
One advantage of the invention is that the ladder-like fixture 22 can be
turned 180 to place the vertical bars 36 near either the inner or outer
surface of the wall. Thus, for a basement wall, the steel bars would be
placed closer to the inside surface of the wall, whereas for a free-standing
cantilevered retaining wall, the steel bars would be placed closer to the
surface of the wall in contact with the soil.
~ he devices 2Z are preferably formed in 8'6" lengths, and are laid
10 with their ends overlapping 6 inches so that when the overlapped ends are
embedded in grout, the ladder devices 2Z form, in effect, a continuo (ls
length of steel, which allows the wires 24, 26 to be figured as part of the
horizontal steel reinforcing for the wall. Other horizontal steel reinforce-
ment bars can therefore be correspondingly reduced in size. The devices
22 would be placed on the horizontal mortar joints at every 3rd or 4th
course of blocks, according to the building code, with the rings 34 of
each ladder aligned vertically with the rings of the ladd0rs below. When
the wall has been built to the desired height, vertical reinforcing bars 36
are inserted down through the rings 34, and the cavities containing the
20 reinforcing bars are filled with grout.
The rings 34 of the ladder-like devices 22 hold the reinforcing bars
36 precisely at the designed locations, and prevent the bar~ from being
displaced while the grout is being poured and puddled. With the vertical
reinforcing bars positively located at the exact location specified by the
design engineer, the full strength of the bars is utilized, and the strength
of the wall is therefore assured. The rings 34 can be located wherever
the design engineer specifies that the vertical bars 36 are to be placed,
and, if desired, two rings can be provided side-by-side on cross wires 28,
as in Fig. 6, one of which is to receive the stub steel bar that is embedded
6~3
. ~
in the concrete footing, and projects upwardly therefrom, while the other
ring receives the vertical reinforcing bar that i9 lowered into the block
cavity from the top of the wall. Alternatively, a single ring 34 might be
. provided at the midpoint of cross wires Z8, or two side-by-side rings
might be provided, as shown in Fig. 6. ~he rings 34 may be spaced apart
longitudinally from one another by any desired distance to meet the engin-
eer's design; or two rings can be provided on each cross wire 28, with
ring located adjacent each face of the block cavity, as when double steel
is required for heavily loaded walls; and the rings can be made with any
10 desired inside diameter to accept any particular size of reinforcing bar 36.
Masons who have tried the invention has found it easy to use, and
approve of its use, as it saves time and money in locating the vertical
reinforcing bars according to specifications. ~he ladder-like fixture 22 is
merely dropped into place on the mortar joint, andthe legs 32 and 42
locate the device in the correct position. No special skill is required, and
no time is w asted. Ihe double-strength legs 32 are not e~sily bent out of
shape, and are inclined approximately 15 from the vertical for ease of
inse rtion.
A slightly modified form of the invention is shown in Fig. 4, where the
20 ladder-like fixture is designated by the reference numeral 2Z'. Ihis partic-
ular embodiment is intended for use in the situation where the bottom
: three or four courses of blocks are made with 12-inch blocks and the re-
mainder with 8-inch blocks, as in Fig. 5. In this case, the bottom blocks
are anchored to the concrete footing 35 by means of stub steel bars 36',
the bottom ends of which are embedded in the concrete, and the top ends
; of which project upwardly from the surface of the footing for approximately
the height of the bottom three or four courses. As the blocks are laid,
they are lowered over the top ends of the stub steel bars 36'. Ihe devices
22' that are used with the bottom three or four courses of wide blocks,
.
-8 -
`` ~ 13
and particularly at the junction of the narrower blocks with the wider
blocks, are provided with a third longitudinal wire 44 which is disposed
between and parallel to outer wires 24' and 26'. Wherever wire 44 crosses
` over the cross wires 28' and 30', it is welded to them to provide additional
strength and rigidity to the ladder. Longitudinal wires 44 and 26' are
spaced apart the same distance that wires 24 and 26 are spaced for the
ladders used in the upper courses o blocks. Ihus wire 44 is embedded in
the transverse mortar joint between the top block of the wide blocks and
the bottom block of the narrower blocks forming the upper portion of the
10 wall. Cross wires 28' have two circular rings 34' formed therein, which
are located to position vertical reinforcing bars 36 and 36' at the correct
position, as shown in Fig. 5.
Cross wire 28' also has downwardly projecting legs 32 ' adajcent the
outer wires 24', 26', and cross wire 30' has a cross piece 40' with down-
wardly projecting legs 42' at each end, which straddle the center web 20
of the block. As in the preceding embodiment, the legs 32' and 42' are
set at a 15 angle to facilitate placement of the ladder on the blocks.
Another form of the invention is shown in Fig.6, where the ladder-like
; fixture is designated by the reference numeral 22" In this case, the cross
20 wires 28" have two rings 34" formed side-by-side, one of which receives
a stub steel bar projecting upwardly from the concrete footing, and the
other receiving a vertical reinforcing bar which is lowered into the block
' cavity from the top of the wall prior to being embedded in grout. Other-
wise, the ladder fixture 22" is generally similar to fixture 2Z in Figs. 1-3.
Fig. 7 shows still another form of the invention, designed specifically
to locate the vertical reinforcing bars in a ~quare column 48 built up of
column blocks S0. Ihe l~locks 50 are laid up, one on top of the other,
forming a square cavity 52 in the center of the column. l~he fixture 46 is
formed of wire 54 bent into a square configuration, with horizontally out-
_9_
~' .
" 1~.216~3
wardly projecting legs 56 at the midpoints of the iour side8 of the squareWelded to the wire 54 on the insides of the four corners are four circular
rings 58. A.lso welded to the wire 54 at the four corners thereof are down-
wardly projecting legs 60, which extend down into the cavity 52 to center
the fixture 46 on the column. Rings 58 may be located anywhere along the
length of the wire 54, as specified by the design engineer, and when the
vertical steel reinforcing bars have been passed down through the rings,
the bars will be positively held in the exact position specified.
Still another form of the invention is shown in Fig. 8, where the fix-
.~
; 10 ture is designated by the reference numeral 6Z. Fixture 62 is also designed
for use in a square column of the type shown in Fig. 7. Fixture 62 also
comprises a wire 64 bent into a square, with circular rings 66 welded to
- f the insides of the four corners, and upwardly projecting legs 68 also weld-
ed to the corners. At their upper ends, the legs are bent horizontally out-
ward àt 70 to form fingers that rest on the top edges of the blocks. ~he
square wire fixture 64 is dropped into the cavity of the column, and legs
68 fit snugly into the corners of th~ s~avity to center the fixture within the
cavity. As in the preceding embodiments, rings 66 may be welded at any
desired location along the length of the wire 64 to position the vertical
20 bars at the exact location specified by the engineer.
:
, -10-
.
: :
