CONCRETE MASONRY REINFORCEMENT

CHAINAGE DE MACONNERIE DE BETON

English Abstract

In a partially grouted concrete masonry wall, the bed joint reinforcement is provided by a set of rings spaced along the mortar between two adjacent courses of blocks and wire strands on opposite sides of the rings. Each of the grouted cells of the wall is surrounded by reinforcing rings embedded in the mortar. The rings support the columns of grouting in the wall and more effectively transfer loads to the bed joint reinforcement than does conventional truss or ladder style bed joint reinforcement. Between courses where bed joint reinforcement is not used, independent rings may be employed to support the grouting columns.

French Abstract

Dans un mur de maçonnerie en béton partiellement cimenté, l'armature des joints d'assise est constituée d'un ensemble d'anneaux espacés le long du mortier entre deux rangées adjacentes de blocs et de fils d'acier de chaque côté des anneaux. Chacune des alvéoles cimentées du mur est encerclée par des anneaux de renforcement noyés dans le mortier. Les anneaux soutiennent les colonnes de cimentation dans le mur et transfèrent les charges vers l'armature des joints d'assise de manière plus efficace que ne le fait l'armature de joint d'assise conventionnelle de type treillis ou échelle. Dans les parties intermédiaires où aucune armature de joint d'assise n'est utilisée, des anneaux indépendants peuvent être employés pour soutenir les colonnes de cimentation.

Claims

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Claims:

1. A joint reinforcement for use in a concrete block wall, the concrete block
wall including a plurality of blocks arranged in plural courses, the blocks
having hollow cores that align in upright cells through the courses at
intervals
along the wall, mortar joining adjacent blocks, and grouting filling selected
ones of the cells, said reinforcement comprising:
a plurality of reinforcing strands along each of the selected cells,
wherein the strands are unembedded in the grouting; and
a plurality of reinforcing rings connected to the reinforcing strands,
each reinforcing ring surrounding the grouting in a respective one of the
selected cells between two adjacent courses.

2. A reinforcement according to Claim 1 wherein the rings are steel
reinforcing
rings.

3. A reinforcement according to Claim 2 including pairs of reinforcing strands
extending along the wall between adjacent courses, the strands being
embedded in the mortar on opposite sides of the hollow cores.

4. A reinforcement according to Claim 3 wherein the reinforcing strands are
wire strands.

5. A reinforcement according to Claim 3, 4 or 5 wherein the reinforcing
strands have an oblong profile.

6. A reinforcement according to any one of Claims 2 through 5 wherein the
reinforcing rings are round wire.

Description

CA 02274239 1999-06-10
CONCRETE MASONRY REINFORCEMENT
FIELD OF THE INVENTION
The present invention relates to the reinforcement of partially grouted
concrete masonry walls.
BACKGROUND
Partially grouted concrete masonry walls of the type in question
conventionally have two types of reinforcement. Vertical reinforcement in the
form of
rebar is used in the grouted cells of the wall. Horizontal reinforcement is
provided by
bed joint reinforcement, typically in a "ladder" or "truss" configuration. In
such
structures, the full capacity of the reinforcement is not utilized because of
the
mismatch between the elastic modulus of the steel of the reinforcement and
that of
the mortar used in fabricating the wall. In addition, the difference between
the
Poisson's ratios of the steel and the concrete grout causes the concrete to
split
prematurely.
The present invention aims at the provision of mechanisms to improve
utilization of the reinforcement.
SUMMARY
According to one aspect of the present invention there is provided a
reinforcement for use in a concrete block wall comprising:
a plurality of blocks arranged in plural courses, the blocks having hollow
cores that align in upright cells through the courses at intervals along the
wall;
mortar joining adjacent blocks;
grouting filling selected ones of the cells; and
reinforcing strands along each of the selected cells,
said reinforcement comprising a plurality of reinforcing rings each
surrounding the
grouting in a respective one of the selected cells between two adjacent
courses.

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The rings support the column of grouting where it passes through the
mortar joint between the blocks, thus mitigating the differences in properties
between
the reinforced cell grouting, the mortar and the reinforcement.
According to another aspect of the present invention there is provided
bed joint reinforcement for a concrete masonry wall that is at least partially
grouted,
said reinforcement comprising:
a pair of spaced apart, substantially parallel side strands; and
a plurality of rings joining the side strands, substantially parallel to the
side strands.
When the reinforcement is installed, the rings surround the grouted
cells in the wall and transfer loads directly from the grouting columns to the
side
strands to reinforce the wall horizontally and reduce stress concentrations.
At the
same time, the rings support the columns of grout as discussed above.
The invention also provides, according to other aspects thereof, walls
incorporating the reinforcing rings and the bed joint reinforcement.
The rings may be of any suitable shape, for example circular, square or
other polygon. They are preferably formed from round steel wire. The side
stands
are preferably steel wire, flattened to present an oblong profile with a
height
approximately equal to that of the rings. It is preferred that the rings are
co-planar
with the side strands and welded tangentially to them. The rings may also be
lapped
and welded, but this increases the thickness of the reinforcement.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings, which illustrate exemplary embodiments
of the present invention:
Figure 1 is an elevation of a masonry wall;
Figure 2 is a plan view of a bed joint reinforcement;

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Figure 3 is a cross section on line 3 - 3 of Figure 2;
Figure 4 is a view along line 4 - 4 of Figure 1; and
Figure 5 is an exploded isometric of the wall.
DETAILED DESCRIPTION
Referring to the accompanying drawings, Figure 1 illustrates a wall 10
composed of masonry blocks 12 arranged in superimposed courses 14. The joints
between adjacent courses and between adjacent blocks in the same course are
formed with mortar 18. The blocks are hollow core blocks with two cavities 19
(Figures 4 and 5) per block. The cavities align through the courses to provide
vertical cells 20 through the wall. At intervals along the wall, the cells
have vertical
steel reinforcing rods 22 extending along their centers. The rods are embedded
in
grout 23 (Figures 4 and 5). The grout forms, with the vertical reinforcing
rods,
vertical columns in the wall's structure.
The wall is also reinforced horizontally with bed joint reinforcement
between selected adjacent courses of the blocks. As illustrated in Figures 2
through
5, the bed joint reinforcement 24 includes two parallel side rods 26. These
are steel
rods flattened in their vertical dimension to present an oval profile. The
rods are
joined by cross links, which are rings 28 that align with cells 20 in the
wall. As
illustrated in Figures 4 and 5, rings are provided to align with alternate
cells along the
wall, although in the illustrated wall, only every sixth cell is grouted.
As shown in the exploded view of Figure 5, the bed joint reinforcement
24 is used in alternate joints. In the intervening joints rings 30 are
embedded in the
mortar around the grouted cells to confine the grout 23.
With this structure, the rings 28 and 30 confine the grouted cells where
they pass through the mortar to support the columns. The rings that are
incorporated
into the bed joint reinforcement transfer loads between the cells and the
steel side

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rods 26 to provide a more effective use of the strength of the side rods 26
than would
be the case if the loads were to be transferred to the side rods through the
mortar.
While particular embodiments of the invention has been described in
the foregoing, it is to be understood that other embodiments are possible
within the
scope of the invention and are intended to be included herein. Thus, for
example,
the rings of the illustrated embodiment are circular in shape but other shapes
may be
employed, including various polygons. The rings are shown parallel to and co-
planar
with the side rods and welded to them at the points of contact. In other
embodiments,
the rings may overlap the side rods, although this is not a preferred
construction. At
those locations where there is no vertical reinforcement, the rings may be
omitted,
and the side rods connected by straight bars. The invention is therefore to be
considered limited solely by the scope of the appended claims.

Representative Drawing