Note: Descriptions are shown in the official language in which they were submitted.
CA 02730837 2011-02-01
LOAD-SHARING BRACING SYSTEM FOR A FLOOR
Field of the Invention
100011 The present invention relates to a load-sharing bracing system. In
particular,
the invention relates to a load-sharing bracing system for a floor.
Description of the Related Art
[00021 Wood floors today are typically built with a plurality of spaced-apart
joists.
The joists may be in the form of sawn lumber joists that are rectangular in
cross-section
or in the form of engineered joists, typically 1-j oists. Flooring such as
decking is typically
attached on top of the joists. Floors so built may be susceptible to annoying
bounce,
vibration, squeaking and the like.
100031 It is known per se to support floor joists with a plurality of cross-
brace
assemblies interposed between the joists so as to promote load-sharing between
the joists.
When a person walks on a conventional floor supported by floor joists, the
cross-brace
assembly enables a plurality of adjacent joists to be engaged. The cross-brace
assembly
acts to transfer impact load from the joist under the person impacting the
floor to adjacent
joists thus reducing floor deflection and vibration amplitude that is felt by
the person(s)
on the floor.
[00041 An example of a known cross-brace assembly is shown in Figures 1 and 6
of
United States Patent No. 4,947,612 to Taylor, which discloses a cross-brace
assembly
comprising a plurality of brace members 18, 19, 20, together with vertical
reinforcement
members 22 and 24, the brace members extending between a pair of joists 10 and
11 and
the whole assembly being connected together via a plurality of truss plates 26
and 28.
[00051 United States Patent No. 5,301,486 to Taylor discloses a cross-brace
assembly
comprising a pair of brace members connected together via a lap joint, a pair
of vertical
1
CA 02730837 2011-02-01
2
reinforcement members and a horizontal member, here too with the assembly
being
connected together via a plurality of truss plates.
[0006] Each of the above assemblies requires a relatively large number of
parts and
may accordingly require a relatively large amount of manufacturing and
installation time.
The greater number of parts of the above systems may also render these systems
more
prone to errors in manufacturing.
[0007] Also, each of those assemblies has a rather ideal, fixed and rigid
geometry that
is intended to exactly fit into the nominal space between the joists, whereas
in a real life,
that space is more random and, as such, such systems may not allow their
assemblies to
fit snugly into this space. A snug connection is critical for the performance
of such
devices and this rigidity may thus render such systems less reliable.
[0008] Also, existing cross-brace assemblies may not provide for passages of
HVAC
services and may not provide means for reinforcing the assemblies when a
homeowner or
tradesperson wants to alter them, by cutting out part of a cross-brace member
for
example, to create space for the passage of HVAC conduits and the like.
[0009] There is accordingly a need for an improved load-sharing bracing system
that
effectively supports floor joists while at the same time requiring fewer parts
and reducing
installation and manufacturing time and costs while at the same time
increasing device
reliability.
BRIEF SUMMARY OF INVENTION
[0010] The present invention provides a load-sharing bracing system disclosed
herein
that overcomes the above disadvantages. It is an object of the present
invention to
provide an improved load-sharing bracing system.
CA 02730837 2011-02-01
3
100111 It is important that a given floor system have a sufficiently high
stiffness to
ensure that its response to impact load is acceptable to homeowners. However,
regardless
of how stiff single joists may be, it was discovered that the floor system
response to an
impact load is principally controlled by both the bracing assembly's stiffness
and the
attachment of the bracing assembly to the joists. The system as herein
described
maximizes its bracing assembly's attachment capacity to the joists thus
allowing use of
the full capacity of the bracing assembly itself. This in turn enables one to
provide a more
cost-effective cross-brace assembly having fewer parts which, with enhanced
attachment
capacity, effectively improves the floor system response to the impact load.
[00121 There is accordingly provided a load-sharing bracing system for a
floor. The
system includes a pair of joists having vertical side faces that are spaced-
apart and
configured to face each other. An x-shaped cross-brace assembly extends
between the
side faces of the joists. The cross-brace assembly has a pair of brace members
connecting
together via a centrally disposed lap joint. Each brace member has a top, a
bottom
opposite the top, and a pair of spaced-apart vertical sides each extending
between the top
and the bottom. The sides are thinner relative to the top and the bottom. The
sides are
arranged perpendicular to the side faces of the joists. Each brace member has
an upper
end configured to abut with an upper portion of the side face of a first one
of the joists.
Each brace member has a lower end configured to abut with a lower portion of
the side
face of a second one of the joists. A first plurality of fasteners are
disposed to extend
through the tops of each of the brace members adjacent to the upper portion of
the side
faces of the joists and extend into the joists. A second plurality of
fasteners are disposed
to extend through the bottoms of each of the brace members adjacent to the
lower portion
of the side faces of the joists and extending into the joists.
100131 There is also provided a load-sharing bracing system for a floor
according to
another aspect. The system has a pair of joists having vertical side faces
that are spaced-
apart and configured to face each other. An x-shaped cross-brace assembly
extends
between the side faces of the joists and has a pair of spaced-apart sides
arranged
perpendicular to the side faces of the joists. A plurality of L-shaped
brackets connect at
CA 02730837 2011-02-01
4
least one of the sides of the cross-brace assembly to the side faces of the
joists. Each
bracket has a first part that abuts with and partially extends along one of
the sides of the
cross-brace assembly. Each bracket has a second part that abuts with and
partially
extends along the side face of one of the joists. A plurality of fasteners are
arranged to
partially extend through the first parts and the second parts of the brackets
and extend
into the brace member and joists, respectively. The brace members thereby
connect to the
joists. This system allows for the removal of a portion of one or two brace
members of
the cross-brace assembly with virtually no loss of stiffness through the
addition of
reinforcing proprietary brackets connecting the remaining portions of the
cross-brace
assembly to the joists. This is an important feature since each floor has HVAC
services
and none of the bracing assemblies of the known art provide such a feature.
[00141 There is further provided a method of installing a load-sharing bracing
system
for a floor. The method includes pre-fabricating a plurality of x-shaped cross-
brace
members. The method includes installing a plurality of longitudinally
extending joists.
The joists each have vertical side faces. The step of installing includes
spacing the
vertical side so as to be spaced-apart from each other and so as to face each
other. The
cross-brace members are shaped to extend between the vertical side faces of
the joists.
The method includes toenailing the cross-brace members to the vertical sides
of the joists.
100151 There is yet further provided an L-shaped bracket for connecting a load-
sharing bracing assembly to a pair of joists. Each joist has a vertical side
face. The
bracing assembly has a vertical surface perpendicular to the side faces of the
joists. The
bracket has a first plate member configured to abut with and partially extend
along the
vertical surface of the bracing assembly. The first plate member has a pair of
spaced-
apart apertures extending therethrough. The apertures are shaped to receive a
first pair of
fasteners and thus enable the first plate member to connect via said first
pair of fasteners
to the bracing assembly. The bracket has a second plate member configured to
abut with
and partially extend along the side face of one of the joists. The second
plate member has
a pair of spaced-apart apertures extending therethrough. The pair of apertures
of the
second plate member are shaped to receive a second pair of fasteners and thus
enable the
CA 02730837 2011-02-01
second plate member to connect via said second pair of fasteners to said one
of the joists.
Each of the pair of apertures of the second plate member has a diameter. The
second plate
member is configured such that the pair of apertures of the second plate
member are
spaced-apart relative to the first plate member by a distance equal to or less
than twice the
5 diameter of said each of the pair of apertures of the second plate member.
BRIEF DESCRIPTION OF DRAWINGS
[00161 The invention will be more readily understood from the following
description
of preferred embodiments thereof given, by way of example only, with reference
to the
accompanying drawings:
Figure 1 is a top perspective view of a load-sharing bracing system according
to one
embodiment, the system having an x-shaped brace assembly comprising a pair of
brace
members connected together via a lap joint, and the system including a
plurality of
longitudinally extending joists in the form of sawn lumber;
Figure 2 is a top perspective view of one of the brace members shown in Figure
1;
Figure 3 is a top perspective view of the other of the brace members shown in
Figure 1;
Figure 4 is an elevation view of the system shown in Figure 1, and also
showing flooring
overlaying the system;
Figure 5 is top plan view of the system shown in Figure 1, with other cross-
brace
assemblies also being shown extending between the joists;
Figure 6 is a plan view of the brace member shown in Figure 3, the brace
member being
partially broken away, and a preferred location for fasteners being shown;
CA 02730837 2011-02-01
6
Figure 7 is a perspective view of the system shown in Figure 1 being subject
to a point
load;
Figure 8 is a graph showing the extent of floor displacement resulting from
six cycles of
2kN (450 lb.) point load applied in increments of 50 lb. in the manner shown
in Figure 7
to the system shown in Figure 7, without detrimental effect on the load-
sharing bracing
system's performance;
Figure 9 is a plan view of the brace member shown in Figure 3 showing a
preferred
location for fasteners according to another embodiment;
Figure 10 is a plan view of the brace member shown in Figure 9 showing a
preferred
location for fasteners according to a further embodiment;
Figure 11 is a top perspective view of a load-sharing bracing system according
to a yet
further embodiment, showing a brace member connecting to a joist via an L-
shaped
bracket;
Figure 12 is a perspective view of the system shown in Figure I1 showing
further L-
shaped brackets and the locations in which they are preferably connected, with
a portion
or leg of one of the brace members being in hidden lines to indicate that it
has been
removed for the passage of HVAC services;
Figure 13 is an elevation view of a load-sharing bracing system according to
yet a further
embodiment, the system including engineered 1joists, the brace assembly being
substantially similar to that shown in Figures 1 to 8 and flooring overlaying
the system;
Figure 14 is an elevation view of a load-sharing bracing system according to
yet another
embodiment, the system including engineered 1 -joists, the brace assembly and
system
being otherwise substantially similar to that shown in Figures 11 and 12, and
flooring
overlaying the system; and
CA 02730837 2011-02-01
7
Figure 15 is an elevation view of a load-sharing bracing system according to
another
embodiment, the system being similar to that shown in Figure 14, with brackets
being
shown according to another embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Referring to the drawings and first to Figure 1, there is shown a load-
sharing
bracing system 11 configured to support flooring 12 as shown in Figure 4. The
system
includes a plurality of longitudinally-extending joists as illustrated by the
pair of joists 14
and 16. The joists have bottoms 22 and 24 and tops 26 and 28 opposite thereof.
The joists
14 and 16 have vertical side faces 18 and 20 that are spaced-apart and
configured to face
each other. The side faces 18 and 20 extend between the bottoms and the tops.
As shown
in Figure 4, the side faces 18 and 20 have upper portions 19 and 21 located
adjacent to
the tops 26 and 28 of the joists and lower portions 23 and 25 located adjacent
to the
bottoms 22 and 24 of the joists. The joists 14 and 16 are preferably in the
form of sawn
lumber in this example, though this is not required.
[0018] The system 11 includes a plurality of x-shaped, prefabricated cross-
brace
assemblies as illustrated by cross-brace assembly 30 extending between the
side faces 18
and 20 of the joists 14 and 16. As shown in Figure 5, other cross-brace
assemblies 31 and
33 are spaced-apart between and along the joists 14 and 16 and are
substantially the same
as the cross-brace assembly 30 shown in Figure 1. Likewise, further cross-
brace
assemblies are spaced-apart between and along other adjacent joists that
underlie the
flooring, as is for example shown in Figure 7 with cross-brace assembly 74
that extends
between joist 14 and further joist 72. Only cross-brace assembly 30 as shown
in Figure 1
will be discussed in detail for ease of explanation. The cross-brace assembly
30
preferably consists only of a pair of brace members 32 and 34 as best shown in
Figures 2
and 3. The brace members are preferably in the form of 2 inches by 3 inches or
2 inches
by 4 inches, Spruce Pine Fir Grade #2 (SPFN2) kiln-dried and planed with a
moisture
CA 02730837 2011-02-01
8
content of less than 19%, to minimize brace member warping and twisting,
though this is
not required.
[00191 The brace members 32 and 34 have tops 36 and 38 and bottoms 40 and 42
as
shown in Figure 4 opposite the tops. As shown in Figures 2 and 3, the brace
members 32
and 34 have a pair of spaced-apart vertical sides 44 and 46, and 48 and 50,
respectively,
which may also be referred to as the sides of the cross-brace assembly. The
tops and
bottoms of the brace members extend between the sides. The sides 44, 46, 48,
and 50 are
thinner relative to the tops 36 and 38 and bottoms 40 and 42. The brace
members are thus
generally rectangular in cross-section. As shown in Figure 5, the sides 44,
46, 48 and 50
of the brace members are arranged perpendicular to the side faces 18 and 20 of
the joists.
[00201 As shown in Figure 2, brace member 32 has an opening or notch 54
extending
through and from side 46 towards side 44, half-way along and through top 36.
Similarly,
as shown in Figure 3, brace member 34 has an opening or notch 56 extending
through
and from side 48 towards side 50, half-way along and through top 38. The
notches 54 and
56 are generally in the shape of rectangular prisms and are configured to
enable the brace
members 32 and 34 to connect together via a centrally disposed lap joint 52 as
shown in
Figure 1. The brace members 32 and 34 are configured to connect together in a
tight,
press-fit manner so as to provide a central connection with a high moment
capacity. This
is because the notches 54 and 56 are equal in size or just slightly wider than
the sides 44,
46, 48 and 50 of the brace members.
100211 The system 11 may also include adhesive 53, as shown in Figure 2,
disposed
along portions of the brace members adjacent to notches 54 and 56. The
adhesive 53
further connects the brace members together and further increases the brace
members'
moment capacity, though adhesive is not strictly required.
[00221 As best shown in Figure 4, the brace members 32 and 34 have upper ends
58
and 60 configured to abut with the upper portions 19 and 21 of the side faces
18 and 20
of the joists 14 and 16. The brace members 32 and 34 have lower ends 62 and 64
CA 02730837 2011-02-01
9
configured to abut with lower portions 23 and 25 of the side faces of the
joists. Ends 58,
60, 62, and 64 are in the form of cut, parallel, vertical planes that smoothly
abut with the
side faces 18 and 20 of the joists and closely extend between and fit within
the space
between the joists. The use of kiln-dried or drier lumber inhibits twisting
and warping of
the brace members and thus further promotes continued good contact between the
brace
members and the joists. The lap joint 52 is preferably interposed midway
between the
upper ends 58 and 60 and the lower ends 62 and 64.
[00231 Referring to Figures 1 and 4, the system 11 includes a first plurality
of
fasteners, as shown by fastener 66, disposed to extend through the tops 36 and
38 of the
brace members in a region of the tops 36 and 38 that is adjacent to the upper
portions 19
and 21 of the side faces 18 and 20 of the joists and extend into the joists.
The system 11
also includes a second plurality of fasteners, as shown by fastener 68 in
Figure 4,
disposed to extend through the bottoms 40 and 42 of the brace members in a
region of the
bottoms that is adjacent to the lower portions 23 and 25 of the side faces 18
and 20 of the
joists and extend into the joists. In this example the fasteners are nails
that are toenailed
to the upper and lower portions of the side faces of the joists 18 and 20.
However,
alternative fasteners such as screws, staples and the like may be used. The
fasteners
preferably extend into the joists at an angle a of 45 degrees relative to the
side faces of
the joists.
100241 Figure 6 shows a preferred arrangement of the fasteners 66 for each of
the
fastening or nailing regions shown in Figure 4 and in this example for the top
38 of brace
member 34. There are preferably provided three fasteners when member 34 is 2
inches by
3 inches, each fastener having a shaft diameter d. There are preferably
provided four
fasteners when member 34 is 2 inches by 4 inches. The fasteners are arranged
in a row
and spaced-apart by a distance equal to at least 8-times the diameter of the
fasteners. The
fasteners are spaced-apart from edge 70 of the top 38 by a distance equal to
12-times the
diameter of the fasteners and in this example by a distance of 1.2 inches.
Outer fasteners
66i and 66iii are spaced-apart by a distance equal to at least 4 times the
diameter of the
fasteners and in this example 0.4 inches from the sides 50 and 48,
respectively, of the
CA 02730837 2011-02-01
brace member. Inner fastener 66ii is spaced-apart from each other and spaced-
apart
relative to fasteners 66i and 66iii, respectively, by a distance equal to at
least 8 times the
diameter of the fasteners, in this example, 0.9 inches.
[0025] The size of the tops and bottoms of the brace members allows the
fasteners to
5 be arranged in more than one row. This is shown in Figure 9 where fasteners
are arranged
in a two row pattern for a load-sharing bracing system 11.1 having a first row
78 of
fasteners and a second row 80 of fasteners spaced-apart therefrom. The system
11.1
shown in Figure 9 is otherwise substantially similar to that shown in Figures
1 to 8, with
like parts having like numbers and function with addition of ".1". A maximum
of four
10 fasteners per row may be used for brace members that are 2 inches by 3
inches in cross-
section. A maximum of six fasteners per row may be used for brace members that
are 2
inches by 4 inches in cross-section. One may also want to add fasteners
through the sides
of the brace members and into the joists so as to provide additional
connection.
[0026] Figure 10 shows a further variation in the arrangement of the
fasteners. The
fasteners are arranged in a two row pattern for a load-sharing bracing system
11.2 having
a first row 78.2 of fasteners and a second row 80.2 of fasteners spaced-apart
therefrom. In
this case fasteners 81 of row 80.2 are staggered relative to the fasteners of
row 78.2.
System 11.2 shown in Figure 10 is otherwise substantially similar to that
shown in
Figures 1 to 8, with like parts having like numbers and function with addition
of ".2".
[0027] Referring back to Figures 1 to 8, the system 11 as described herein
reacts very
well to a force applied to it. A floor's ability to withstand the impact,
which is in essence
a design check for the serviceability of the floor, is typically tested
according to building
codes based on point load deflection criteria. This is shown in Figures 7 and
8. Figure 7
shows the system 11 with the addition joist 72, the additional cross-brace
assembly 74
which is substantially the same as assembly 30, flooring 12 extending over top
of the
system 11 and a force as indicated by arrow 76 being applied to the flooring
12. The
responsiveness of the system 11 is shown in Figure 8.
CA 02730837 2011-02-01
11
100281 The system was subjected to a repetitive load of 2kN (450 lb.) as per a
standard test for intermediate devices in Canada (CCMC Master Format 06190).
The
corresponding displacement of the flooring was then measured. The test is now
being
introduced in ASTM standard procedures. Even after six cycles there is no
noticeable
yield in the device or device connections to the joists. A displacement
downwards of the
flooring 12, from the perspective of Figure 7 and as set out on the x-axis of
the graph in
Figure 8, of less than 0.10 inches results from a given force against the
floor of 450
pounds, as is set out on the y-axis of the graph,. As is evident from the test
results
displaced on the graph, the system also responds very linearly, meaning that
there is no
yield in connections between the brace assembly 30 and joists.
100291 Figures 11 and 12 show a load-sharing bracing system 11.3 according to
a
further embodiment. Like parts have like numbers and function as the
embodiment
shown in Figures 1 to 8 with the addition of ".3". System 11.3 is
substantially the same as
system 11 shown in Figures 1 to 8 with the exception that a plurality of L-
shaped
brackets as shown by L-shaped brackets 82 and 84 in Figure 11, are used in
addition to
fasteners (such as nails) to connect the sides 46.3 and 44.3 of the brace
members 32.3 to
the side faces 18.3 of the joists 14.3.
[00301 L-shaped bracket 82 has a first part or plate member 86 that abuts with
and
partially extends along side 46.3 of the brace member 32.3. First plate member
86 has a
top edge 87 and a bottom edge 89 opposite thereof. Bracket 82 has a first pair
of
apertures 88 that extend through its first plate member 86 and which in this
example are
staggered. Bracket 82 has a second part or plate member 90 that abuts with and
partially
extends along side face 18.3 of joist 14.3. Second plate member has a top edge
97 and a
bottom edge opposite thereof 99. Second plate member 90 is disposed
perpendicular to
the first plate member 86. The plate members 86 and 90 are connected via
corner 101,
which defines an axis 103. In this example edges 87 and 89 of plate member 86
extend
horizontally from the perspective of Figure 11 and relative to plate member
90. Bracket
82 has a second pair of apertures 92 that extend through its second plate
member 90.
Each of the apertures 92 has a diameter D. The apertures 92 are disposed in a
row
CA 02730837 2011-02-01
12
adjacent to the bend of the bracket and adjacent to the first plate member 86
of the
bracket 82. The second plate member 90 is configured such that the apertures
92 are
preferably spaced-apart relative to the first plate member 86 by a distance
equal to or less
than twice the diameter of each of the apertures 92, in this example by a
distance of less
than the diameter of each of the apertures 92. Thus, apertures 92 are arranged
so as to be
significantly adjacent to side 46.3 of the brace member 32.3.
[00311 A plurality of fasteners, in this example screws 94, extend through the
apertures of the first and second plate members of the bracket 82 and into the
brace
member 32.3 and joist 14.3, the brace members and joists connecting together
thereby.
Because the brace members are rectangular in cross-section with tops 36.3
being
relatively wide, this enables longer fasteners to be used for connecting first
plate member
86 of the bracket to the brace member 32.3.
100321 Advantageously, the locations of apertures 92 close to side 46.3 of
brace
member 36.3, together with screws 94 passing therethrough, increases
connection
stiffness. This is because two forces - one force pulling the brace member
32.3, and the
other force holding the bracket 82 to the joist 14.3, are practically in the
same plane. This
arrangement inhibits any moment acting on the second plate member 90 of the
bracket,
which would otherwise occur if the apertures 92 were more spaced-apart from
the brace
member 32.3 in a more conventional bracket arrangement, such as is shown by
apertures
91 in Figure 11, which are not required in the system as herein described.
Such seemingly
minor details in the fastener and aperture arrangement as herein disclosed
make a big
difference in the overall stiffness of the system 11.3.
[00331 Referring to Figures 11 and 12, preferably L-shaped brackets 82 are
arranged
on both sides 46.3 and 44.3 of brace member 32.3 adjacent to the member's
lower end
62.3 and upper end 58.3, as shown by bracket 95 in Figure 12. Brackets may
also be
added to the sides of brace member 34.3 for further support though this is not
required
nor shown in the embodiment shown in Figure 12.
CA 02730837 2011-02-01
13
[00341 The use of brackets further enhances the strength of connection between
the
brace members and the joists. This enables one or two portions or legs of the
brace
members, as shown by leg 96 in ghost lines for brace member 34.3, to be
removed and to
create more space thereby between the joists to better facilitate servicing
and/or the
disposal of heating, ventilation, and air conditioning (HVAC) service
conduits, wiring
and the like.
[00351 Figure 13 shows a load-sharing bracing system 11.4 according to yet a
further
embodiment. Like parts have like numbers and function as the embodiment shown
in
Figures 1 to 8 with the addition of ".4". The system 11.4 is substantially the
same as that
shown in Figures 1 to 8 with the exception that joists 14.4 and 16.4 are
engineered I-
joists, rather than sawn lumber. Joists 14.4 have chords 98 and 100 at their
upper portions
19.4 and 21.4, chords 102 and 104 at their lower portions 23.4 and 25.4, and
web
members 106 and 108 received by and extending between the chords 98 and 102,
and 100
and 104, respectively. The chords provide the side faces to which the brace
members 32.4
and 34.4 connect via fasteners 66.4 and 68.4.
[00361 Figure 14 shows a load-sharing bracing system 11.5 according to yet
another
embodiment. Like parts have like numbers and function as the embodiment shown
in
Figures 1 to 8 and 11 to 13 with the addition of ".5". The system 11.5 is
substantially the
same as that shown in Figure 13 with the exception that L-brackets 82.5 and
95.5 are
used to connect brace member 32.5 to the side faces of chords 98.5 and 104.5.
Leg 96.5
has been removed from brace member 34.5 to create a larger opening for HVAC
services.
The L-brackets are substantially the same as those described in Figures 11 and
12.
100371 Figure 15 shows a load-sharing bracing system 11.6 according to another
embodiment. Like parts have like numbers and function as the embodiment shown
in
Figures 1 to 8 and 11 to 13 with the addition of ".6". The system 11.6 is
substantially the
same as that shown in Figure 14 with the exception that the L-shaped brackets
as shown
by bracket 82.6 have first plate members 86.5 with top edges 87.5 and bottom
edges 89.5
that extend in parallel with top 38.5 and bottom 40.5 of brace member 34.5.
Thus the first
CA 02730837 2011-02-01
14
plate members follow the slope of the brace members in this embodiment. Put
another
way, the top edge 87.5 and the bottom edge 89.5 of the first plate member 86.5
extend
outwards at a non-perpendicular angle of P relative to axis 103.5. In this
example, edges
87.5 and 89.5 are angularly spaced-apart from said axis 103.5 by an angle of
(3 of
approximately 60 degrees relative to said axis, though this angle will vary
depending on
the slope of the brace members.
[00381 While the slanted brackets 82.6 are shown in Figure 15 for use with I -
Joists,
such slanted brackets may also be used for the sawn lumber joists that are,
for example,
shown in Figures 11 and 12.
100391 The systems as herein described reduce floor bounce, vibration and
squeaking
arising from an impact foot-steps load on the floor, by reducing deflection
amplitude and
the floor's dynamic response work, while at the same time increasing floor
frequency and
damping. This significantly increases floor performance in the serviceability,
strength and
stiffness capacity and reliability domains. An increase in damping of the
floor is
generated by elastic deformation of the bracing assembly where the brace
members are
bent around the pivot point in the central lap joint. A significant part of
the impact energy
is absorbed in order to deform the bracing assembly. Put another, the systems
as herein
described reduce vibration or creaking arising from a footstep loads on the
floor, reduce
point load deflection in the middle of the flooring, reduce floor dynamic
response work
under footstep loads, significantly increase vibration serviceability
performance of floors
and also act to increase strength and stiffness capacity. The systems provide
an elastic
response to loads by bending their members, and thus absorbing impact energy
imparted
on the floor and reducing floor vibration amplitude. In addition to reduction
of floor
vibration amplitude due to the increase floor damping ratio, floor vibration
ends (fades-
out) more rapidly than with known brace assemblies of the prior art.
100401 The systems as herein described result in better performing floors that
use less
lumber compared to the other known systems for supporting floors. The systems
as
herein described thus result in economic savings and, by requiring fewer
parts, are more
CA 02730837 2011-02-01
eco-friendly. Also, the assemblies as herein described, by eliminating the
need for
additional vertical reinforcement members and/or horizontal members, provide
yet
further space and accommodation for heating, ventilation, air conditioning and
electrical
cables (HVAC) service conduits and the like that may pass between the joists.
5 [00411 The systems as herein described are optimized for and are
particularly well
suited for sawn lumber floors and also for roof joists. The systems and
assemblies may be
used in the initial construction of buildings and also for retrofitting
existing structures.
[00421 It will be appreciated that many variations are possible within the
scope of the
invention described herein. Also, it will be understood by someone skilled in
the art that
10 many of the details provided above are by way of example only and are not
intended to
limit the scope of the invention which is to be determined with reference to
the following
claims.
