U.S. patent application number 10/507450 was filed with the patent office on 2005-11-10 for connector assembly.
Invention is credited to Patrick, Mark.
Application Number | 20050246988 10/507450 |
Document ID | / |
Family ID | 27808172 |
Filed Date | 2005-11-10 |
United States Patent
Application |
20050246988 |
Kind Code |
A1 |
Patrick, Mark |
November 10, 2005 |
Connector assembly
Abstract
Disclosed is a connector assembly for connecting together a
structural component and a concrete body. The connector assembly is
capable of resisting shear forces between the structural component
and the concrete body. The connector assembly includes a connector
adapted to be embedded in concrete and adapted to be attached to
the structural component, and a connector element that is adapted
to surround the connector and form a barrier that is spaced from
the connector and confines concrete around the connector. A clip
for interconnecting the connector and connector element is also
disclosed. An integrally formed connector element assembly that
includes a connector element and a clip is also disclosed.
Inventors: |
Patrick, Mark; (New South
Wales, AU) |
Correspondence
Address: |
Richard L. Byrne
700 Koppers Building
436 Seventh Avenue
Pittsburgh
PA
15219-1818
US
|
Family ID: |
27808172 |
Appl. No.: |
10/507450 |
Filed: |
April 7, 2005 |
PCT Filed: |
March 12, 2003 |
PCT NO: |
PCT/AU03/00288 |
Current U.S.
Class: |
52/309.11 |
Current CPC
Class: |
E04B 2005/237 20130101;
E04C 3/294 20130101; E04B 5/29 20130101; E04C 5/0645 20130101; E04B
5/14 20130101; E04B 5/40 20130101 |
Class at
Publication: |
052/309.11 |
International
Class: |
E04C 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 12, 2002 |
AU |
PS 1059 |
Jun 21, 2002 |
AU |
PS 3098 |
Sep 2, 2002 |
AU |
2002951162 |
Claims
1: A connector assembly for connecting together a structural
component and a concrete body wherein the connector assembly is
capable of resisting shear forces between the structural component
and the concrete body and includes: (a) a connector adapted to be
embedded in concrete and adapted to be attached to the structural
component; and (b) a connector element that is adapted to surround
the connector and form a barrier that is spaced from the connector
and confines concrete around the connector.
2: The connector assembly defined in claim 1 wherein the connector
and the connector element are separate components and the connector
assembly further includes a means for holding the connector element
around the connector.
3: The connector assembly defined in claim 2 wherein the holding
means is a clip extending between the connector and the connector
element.
4: The connector assembly defined in claim 3 wherein the connector
includes a shank with one end adapted to be embedded in concrete
and the other end adapted to be attached to the structural
component, and wherein the clip includes: (a) a means for coupling
the clip to a section of the connector element, and (b) a plurality
of legs formed from resilient material that extend inwardly and
have inner ends that describe an opening that can receive the shank
of the connector, and which opening has a diameter that is less
than that of the shank, whereby in use the legs deflect when the
clip is pushed over the shank so that the shank extends through the
opening and the inner ends of the legs contact the shank and
thereby couple the clip to the shank.
5: The connector assembly defined in claim 2 wherein the holding
means is adapted to hold the connector element from the connector
so that there is a spacing of at least 20 mm between the
components.
6: The connector assembly defined in claim 2 wherein the holding
means is adapted to hold the connector element from the connector
so that there is a spacing of at least 25 mm.
7: The connector assembly defined in claim 2 wherein the holding
means is adapted to hold the connector element from the connector
so that there is a spacing of at least 30 mm.
8: The connector assembly defined in claim 2 wherein the holding
means is adapted to hold the connector element from the connector
so that there is a spacing of at least the maximum size of
aggregate in concrete in the concrete body between the
components.
9: The connector assembly defined in claim 2 wherein the holding
means is adapted to hold the connector element from the connector
so that there is a spacing of least 1.25 times the maximum size of
aggregate in concrete in the concrete body.
10: The connector assembly defined in claim 2 wherein the holding
means is adapted to hold the connector element from the connector
so that there is a spacing of at least 1.5 times the maximum size
of aggregate in concrete in the concrete body.
11: The connector assembly defined in claim 1 wherein the connector
element is selected from the group which includes a ring of solid
material, a ring of mesh, and a coil with small pitch windings.
12: The connector assembly defined in claim 11 wherein the
connector element is a coil with small pitch windings and the ends
of the coils are closed to facilitate the development of hoop
stresses in the coil.
13: The connector assembly defined in claim 11 wherein the
connector element is a continuous ring of solid material, such as
steel.
14: The connector assembly defined in claim 1 wherein, in a
situation in which the concrete body is supported by a profiled
decking having an upstanding rib or ribs separated by pans and an
underlying structural framework of beams, the connector element is
annular.
15: The connector assembly defined in claim 14 wherein the
connector element has a height approximately 60%-80% the height of
the rib or ribs on the decking.
16: A composite structure includes a structural framework of beams,
a decking on the structural framework, a concrete body on the
decking, and a connector assembly, the connector assembly
including: (a) a connector embedded in concrete and attached to the
structural framework; and (b) a connector element that surrounds
the connector and forms a barrier that is spaced from the connector
and confines concrete around the connector.
17: The composite structure defined in claim 16 wherein the
connector assembly includes a means that holds the connector
element around the connector.
18: The composite structure defined in claim 17 wherein the holding
means is a clip extending between the connector and the connector
element.
19: The composite structure defined in claim 16 wherein the spacing
of the connector element from the connector is at least 20 mm.
20: The composite structure defined in claim 16 wherein the spacing
of the connector element from the connector is at least 25 mm.
21: The composite structure defined in claim 16 wherein the spacing
of the connector element from the connector is at least 30 mm.
22: The composite structure defined in claim 16 wherein the spacing
of the connector element from the connector is at least the maximum
size of aggregate in concrete in the concrete body.
23: The composite structure defined in claim 16 wherein the spacing
of the connector element from the connector is at least 1.25 times
the maximum size of aggregate in concrete in the concrete body.
24: The composite structure defined in claim 16 wherein the spacing
of the connector element from the connector is at least 1.5 times
the maximum size of aggregate in concrete in the concrete body.
25: A shear connector assembly for use in construction of concrete
composite structures having a concrete body supported by a decking
on a structural framework, the shear connector assembly including:
(a) at least one shear connector stud adapted to be permanently
fixed through the decking; and (b) a connector element adapted to
form a barrier surrounding at least one connector stud a spaced
distance therefrom to confine the concrete around the stud.
26: The shear connector assembly defined in claim 25 further
includes a means for holding the connector element around the
connector stud and concentric of the stud.
27: The shear connector assembly defined in claim 26 wherein the
holding means is a clip extending between the connector stud and
the connector element.
28: A method of forming a composite concrete structure including
the steps of: (a) assembling a structural framework incorporating
interconnected cross-beams and a decking mounted on the beams; (b)
permanently fixing connectors in the form of shear connector studs
through the decking and aligned with the beams; (c) positioning a
connector element in relation to the decking wherein the element
forms a barrier surrounding at least one connector stud a spaced
distance therefrom; and (d) pouring concrete on the decking to form
a composite structure.
29: The method defined in claim 28 further includes distancing the
connector stud and the surrounding connector element from the
decking rib at which concrete failure is most likely to occur.
30: A clip for use with the connector assembly defined in claim 1
includes: (a) a means for coupling the clip to a section of the
connector element, and (b) a plurality of legs formed from
resilient material that extend inwardly and have inner ends that
describe an opening that can receive a section of the connector,
and which opening has a diameter that is less than that of the
connector section, whereby in use the legs deflect when the clip is
pushed over the connector so that the connector section extends
through the opening and the inner ends of the legs contact the
connector section and thereby couple the clip to the connector.
31: The clip defined in claim 30 wherein the legs are formed to
enable the legs to flex at least in one direction, when in use the
clip is pushed over the connector to locate the clip on the
connector.
32: The clip defined in claim 30 wherein the legs are formed to
enable the legs to flex in two mutually perpendicular directions,
when in use the clip is pushed over the connector to locate the
clip on the connector.
33: The clip defined in claim 30 wherein at least one of the legs
includes an upward crank.
34: The clip defined in claim 33 wherein the leg or legs that
include the cranked end further include a section that is formed to
increase the flexibility of the leg.
35: The clip defined in claim 34 wherein the by section is in the
form of a curved bend in the leg outwardly of the cranked end.
36: The clip defined in claim 30 wherein the inner ends of the legs
are relatively wide to enable the legs to grip the connector
section securely.
37: The clip defined in claim 30 wherein the inner ends of the legs
include projections that enable the legs to grip the connector
section securely.
38: The clip defined in claim 30 wherein the legs are formed so as
to minimise interference to concrete flowing into the volume
defined by the connector element that enclose the connector.
39: The clip defined in claim 30 wherein the means for coupling the
clip to the section of the connector element includes a plurality
of clasps that can clip onto the section of the connector
element.
40: A connector element assembly for use in a connector assembly
for connecting together a concrete body and a structural component,
wherein the connector assembly includes the connector element
assembly and a connector adapted to be embedded in concrete and
adapted to be connected to the structural component, and the
connector element assembly includes: (a) a connector element that
defines a barrier to confine concrete around the connector, and (b)
an integrally formed clip section for coupling the connector
element to the connector.
41: The connector element assembly defined in claim 40 wherein the
clip section includes a plurality of legs formed from resilient
material that extend inwardly from a section of the barrier section
and have inner ends that describe an opening that can receive a
section of the connector and have a diameter that is less than that
of the connector section, whereby in use the legs deflect when the
connector element is pushed over the connector so that the
connector extends through the opening and the inner ends of the
legs contact the connector section and thereby couple the connector
element to the connector with the barrier section positioned to
surround the connector.
42: The connector element assembly defined in claim 41 wherein the
legs are formed so that the legs can flex at least in one
direction, when in use the connector element is pushed over the
connector to locate the connector element on the connector.
43: The connector element assembly defined in claim 41 wherein the
legs are formed so that the legs can flex in two mutually
perpendicular directions, when in use the connector element is
pushed over the connector to locate the connector element on the
connector.
44: The connector element assembly defined in claim 41 wherein at
least one of the legs includes an upward crank.
45: The connector element assembly defined in claim 44 wherein the
leg or legs that include the cranked end further include a first
leg section that is formed to increase the flexibility of the
leg.
46: The connector element assembly defined in claim 45 wherein the
first leg section is in the form of a curved bend in the leg
outwardly of the cranked end.
47: The connector element assembly defined in claim 41 wherein the
inner ends of the legs are relatively wide to enable the legs to
grip the connector section securely.
48: The connector element assembly defined in claim 41 wherein the
inner ends of the legs include projections that enable the legs to
grip the connector section securely.
49: A method of manufacturing the connector element assembly
defined in claim 40 includes stamping a flat blank from a steel
sheet, the blank having (a) a rectangular section that corresponds
to the barrier section and (b) 4 four elongate members extending
from one side of the rectangle that correspond to the legs of the
clip section, folding the rectangular section of the blank to form
the barrier section, and shaping the elongate members to form the
legs of the clip section.
50: A method of manufacturing the connector element assembly
defined in claim 40 includes pressing a cup-shaped member from a
steel sheet, the cup-shaped member having a cylindrical wall that
forms the barrier section, and stamping the base to form the legs
of the clip section.
Description
[0001] The present invention relates to connector assemblies for
attaching concrete bodies to structures, for example in composite
slabs, columns, beams or any structure attached to concrete slabs,
blocks, etc.
[0002] The present invention also relates to connector elements
that can be used as part of the connector assemblies.
[0003] The present invention also relates to clips that can be used
as part of the connector assemblies.
[0004] In one form, the present invention relates to connector
assemblies that include connectors in the form of shear connector
studs that form the main connection between a frame structure and a
concrete slab.
[0005] In addition, in one form, the present invention relates to
connector elements that can be used with the shear connector
studs.
[0006] In addition, in one form, the present invention relates to
clips that can be used with the shear connector studs and the
connector elements.
BACKGROUND TO THE INVENTION
[0007] Forming concrete composite structures in building
construction involves assembling a structural framework with
cross-connecting primary beams and secondary beams, and laying a
ribbed decking across the supporting primary and secondary beams.
Reinforcing bars or mesh are then layed on top of the decking.
Concrete is poured on top of the decking to complete the composite
structure. In construction works the structural framework is
usually made of steel. FIG. 1 illustrates an example of a
steel/concrete composite floor. When the concrete hardens and
reaches sufficient compressive strength, the decking provides the
main reinforcement for the concrete slab and the slab becomes the
top flange of the composite beam.
[0008] Connectors in the form of shear connector studs are often
used to strengthen the connection between the steel framework and
concrete slab. The studs are fixed, generally welded, upright
through the steel decking or through a pre-punched hole in the
decking before the concrete is poured and are placed above the
primary or secondary beams. Once the studs are cast in concrete,
they become an important part of the connection formed between the
steel framework and concrete slab.
[0009] Depending on the profile of the decking and the nature of
the studs, the strength, ductility and efficiency of the shear
connection formed between the concrete slab and framework can under
ultimate load conditions lead to the common problem of rib
punch-through failure.
[0010] Referring by way of example to steel/concrete composite
structures, rib punch-through failure occurs when the studs are
subjected to longitudinal shear forces between the concrete and
steel framework. The weight of the structure and the load it
supports have the effect of thrusting the concrete against one side
of each stud creating concentrated stresses at the base of the stud
and forming a break-away wedge in the concrete which, under the
longitudinal shear force, is pushed into the ribs of the steel
decking and away from the studs. This situation is illustrated in
FIG. 2A. Arrow A indicates the direction of shear force in the
concrete C against the stud S fixed through decking D to steel beam
SB. The break-away concrete wedge is denoted by W. With the steel
stud no longer confined by concrete around its base, it can be bent
relatively easily under the effects of the shearing force. This
mode of failure significantly reduces the shear strength of the
welded studs, making their shear force/slip behaviour possibly
brittle and overall reducing the strength of the composite
structure. The likelihood of punch-through failure increases as the
number of shear connectors per pan increases and/or as the size of
the connector increases.
[0011] Ductility is a desirable feature of shear connector studs
and in some countries it is mandatory in their national design
Standards that the shear connector studs in composite structures be
ductile. Ductility can be assessed according to the relationship
between the shear force and slip, where the slip occurs
longitudinally between the concrete slab and steel beam. The slip
is indicated in FIG. 2A by Dimension B. The definition of a ductile
shear connector stud in some national design standards is one
having a characteristic slip capacity exceeding 6 mm. Noting that
slip capacity in a solid slab increases with shank diameter, studs
with certain dimensions are considered ductile. For example, some
national design Standards accept a headed stud as being ductile if
the stud has an overall length after welding of at least 4 times
the shank diameter, and with a diameter of not less than 16 mm and
not exceeding 22 mm.
[0012] Areas most prone to cracks and wedges forming in concrete
slabs or structures are regions close to edges or voids. Examples
of voids include profiled ribbing on steel decking creating
notch-like voids in the concrete body, while hollow cores in
pre-cast concrete also create voids. Of the open or closed type
variety of steel decking ribs the more significant problems are
associated with the open type ribs which are more responsible for
creating notch-like voids in the concrete body.
[0013] Rib punch-through failure occurs predominantly in secondary
beams, that is beams spanning effectively perpendicular to the
decking ribs, because with secondary beams the thrust forces are
directed across the ribbed decking and are thus more likely to
carry the effects of voids in the ribs to the stud shanks between
the ribs. The concrete layer in composite slabs is generally in
compression whilst the steel beams underneath are in tension.
Accordingly, the compressive force in the concrete reduces from the
middle of a beam, where the moments are greatest, to the ends of
typcially simply supported composite beams where the moments reduce
to zero. This describes a composite beam in positive bending, but
longitudinal shear forces also develop in the negative moment
regions in continuous composite beams which can also lead to rib
punch-through failure. In primary beams the phenomenon of rib
punch-through failure is less likely because the shear forces run
parallel to the decking ribs and therefore the rib voids are less
likely to affect the studs between the ribs. This is not to say
that rib punch-through failure does not occur in primary beams
because even though the shear force runs parallel to the decking
ribs, concrete surrounding each stud is still known to be thrust
laterally to the decking sheets through the sides of the open ribs.
Haunch width of the concrete can be a critical factor in this
regard, as can the presence of reinforcing steel.
[0014] In taking the above problems into account at the design
stage, empirical design formulae have been developed for
determining the design shear capacity of studs used in composite
structures. Whilst the formulae can be of guidance for simple
constructions, they are relatively inaccurate in practice.
[0015] It is thought that placing studs in pairs improves the
strength of the shear connection, however quite the opposite can be
found to be true with strength and ductility actually reduced due
to rib punch-through failure.
[0016] The above problems are not exclusive to concrete composite
beams but are also found in structures where a component is
attached to a concrete body through bolts or fasteners embedded in
the concrete body. The connected structure may be a pole, beam, leg
of a larger structure, or the like. FIG. 2B illustrates such a
situation where two bolts B cast in a concrete slab C connect a
structural component SC to the concrete slab through a plate P to
which the bolts are connected with nuts N. With the upper shear
force travelling in the direction of Arrow A, a cracked wedge W is
likely to form at the free edge FE of the concrete slab. The free
edge has a similar effect on the casting-bolts as the voids in the
composite beam examples given above, that is, the free edge is a
point of weakness in the concrete where a crack may form. If a
connecting bolt is located close to the free edge illustrated in
FIG. 2B, a wedge of concrete breaking off at the free edge could
weaken or dislodge concrete around the embedded bolt and weaken the
bolt's hold in the concrete. The resulting problem is equivalent to
rib punch-through failure in composite beams.
[0017] A solution is needed to maintain the integrity and strength
of composite concrete structures and overcome the adverse effects
resulting from the formation of cracks and wedges in concrete
composite structures.
SUMMARY OF THE INVENTION
[0018] According to the present invention there is provided a
connector assembly for connecting together a structural component
and a concrete body wherein the connector assembly is capable of
resisting shear forces between the structural component and the
concrete body and includes:
[0019] (a) a connector having a shank with one end adapted to be
embedded in concrete and the other end adapted to be attached to
the structural component; and
[0020] (b) a connector element that is adapted to surround the
connector and form a barrier that is spaced from the connector and
confines concrete around the connector.
[0021] Preferably the connector assembly includes a means for
holding the connector element around the connector.
[0022] Preferably the holding means is a clip extending between the
connector and the connector element.
[0023] Preferably the connector has a shank with one end adapted to
be embedded in concrete and the other end adapted to be attached to
the structural component.
[0024] With such an arrangement preferably the clip includes:
[0025] (a) a means for coupling the clip to a section of the
connector element, and
[0026] (b) a plurality of legs formed from resilient material that
extend inwardly and have inner ends that describe an opening that
can receive the shank of the connector, and which opening has a
diameter that is less than that of the shank, whereby in use the
legs deflect when the clip is pushed over the shank so that the
shank extends through the opening and the inner ends of the legs
contact the shank and thereby couple the clip to the shank.
[0027] Preferably the holding means is adapted to hold the
connector element from the connector so that there is a spacing of
at least 20 mm between the components.
[0028] More preferably the holding means is adapted to hold the
connector element from the connector a spacing of at least 25
mm.
[0029] More preferably the holding means is adapted to hold the
connector element from the connector so that there is a spacing of
at least 30 mm.
[0030] Preferably the holding means is adapted to hold the
connector element from the connector so that there is a spacing of
at least the maximum size of aggregate in concrete in the concrete
body between the components.
[0031] More preferably the holding means is adapted to hold the
connector element from the connector so that there is a spacing of
least 1.25 times the maximum size of aggregate in concrete in the
concrete body.
[0032] More preferably the holding means is adapted to hold the
connector element from the connector so that there is a spacing of
at least 1.5 times the maximum size of aggregate in concrete in the
concrete body.
[0033] The connector element may be, by way of example, a ring of
solid material, specifically galvanised steel, a ring of mesh or a
coil with small pitch windings.
[0034] In a situation where the connector element is a coil with
small pitch windings, preferably the ends of the coils are closed
to facilitate the development of hoop stresses in the coil.
[0035] Preferably the connector element is a continuous ring of
solid material, such as steel.
[0036] In the embodiment of the solid steel ring connector element,
preferably at least the rings are cut from a length of galvanised
steel tube. The rings preferably have an outer diameter of 76 mm
and a wall 2 mm thick. High tensile steel of 350 MPa proof stress
is preferred over lower grade steel. The connector element is
preferably kept centrally in position before the concrete is poured
with a restraining clip that defines the means for holding the
connector element around the connector.
[0037] In a situation in which the concrete body is supported by a
profiled decking having an upstanding rib or ribs separated by
pans, preferably the connector element is annular and preferably
has a height approximately 60%-80% the height of the rib or ribs on
the decking and ideally 70% the height of the rib or ribs.
[0038] The connector element is preferably provided with lateral
cross plates on opposite sides of the element wherein the cross
plates are adapted to support reinforcing rods extending parallel
to the decking ribs to assist in confining the concrete around the
connector.
[0039] According to the present invention there is further provided
a composite concrete structure including a concrete body and a
structural component connected together by way of a connector
assembly, the connector assembly including:
[0040] (a) a connector embedded in concrete and attached to the
structural component; and
[0041] (b) a connector element that surrounds the connector and
forms a barrier that is spaced from the connector and confines
concrete around the connector.
[0042] Preferably the connector assembly includes a means holding
the connector element around the connector.
[0043] Preferably the holding means is a clip extending between the
connector and the connector element.
[0044] Preferably the spacing of the connector element from the
connector is at least 20 mm.
[0045] More preferably the spacing of the connector element from
the connector is at least 25 mm.
[0046] More preferably the spacing of the connector element from
the connector is at least 30 mm.
[0047] Preferably the spacing of the connector element from the
connector is at least the maximum size of aggregate in concrete in
the concrete body.
[0048] More preferably the spacing of the connector element from
the connector is at least 1.25 times the maximum size of aggregate
in concrete in the concrete body.
[0049] More preferably the spacing of the connector element from
the connector is at least 1.5 times the maximum size of aggregate
in concrete in the concrete body.
[0050] In one embodiment, the connector element may surround more
than one connector.
[0051] According to the present invention there is still further
provided a shear connector assembly for use in construction of
concrete composite structures having a concrete body supported by a
decking on a structural framework, the shear connector assembly
including:
[0052] (a) at least one shear connector stud adapted to be
permanently fixed through the decking; and
[0053] (b) a connector element adapted to form a barrier
surrounding at least one connector stud a spaced distance therefrom
to confine the concrete around the connector stud.
[0054] Preferably the shear connector assembly includes a means for
holding the connector element around the connector stud and
concentric of the stud.
[0055] Preferably the holding means is a clip extending between the
connector and the connector element.
[0056] According to the present invention there is still further
provided a method of forming a composite concrete structure
including:
[0057] (a) assembling a structural frame incorporating
interconnected cross-beams and a decking mounted on the beams;
[0058] (b) permanently fixing shear connector studs upright through
the decking and aligned with the beams;
[0059] (c) positioning a connector element in relation to the
decking wherein the element forms a barrier surrounding at least
one stud a spaced distance therefrom; and
[0060] (d) pouring concrete on the decking to form a composite
structure.
[0061] Ideally, the method includes cutting more than one connector
element from a length of steel tube.
[0062] The method further includes distancing the stud and
surrounding connector element from the decking rib at which
concrete failure is most likely to occur.
[0063] According to the present invention there is further provided
a clip for use with the above-described connector assembly.
[0064] The purpose of the clip is to facilitate locating the
connector element in relation to the connector. This is a
particularly important issue in the difficult working environment
in which the connector assembly is generally used.
[0065] In general terms, the clip includes:
[0066] (a) a means for coupling the clip to a section of the
connector element, and
[0067] (b) a plurality of legs formed from resilient material that
extend inwardly and have inner ends that describe an opening that
can receive a section of the connector, and which opening has a
diameter that is less than that of the connector section, whereby
in use the legs deflect when the clip is pushed over the connector
so that the connector section extends through the opening and the
inner ends of the legs contact the connector section and thereby
couple the clip to the connector.
[0068] The above described clip makes it possible to effectively
lock the clip and thereby the connector element to the
connector.
[0069] Preferably the legs are formed to enable the legs to flex in
at least one direction, when in use the clip is pushed over the
connector to locate the clip on the connector.
[0070] Preferably the legs are formed to enable the legs to flex in
two mutually perpendicular directions, when in use the clip is
pushed over the connector to locate the clip on the connector.
[0071] Preferably at least one of the legs includes an upward
crank.
[0072] The cranked end facilitates guiding the clip onto the
connector.
[0073] In addition, the cranked end facilitates initially locating
the clip in the correct orientation in relation to the connector
section. Specifically, the cranked end provides an obvious visual
indication of the correct orientation of the clip in relation to
the connector section.
[0074] In addition, the cranked end increases resistance to sliding
movement of the clip after it has been located on the connector
section. Specifically, sliding movement tends to cause the upwardly
cranked end or ends to dig into the connector section and thereby
increase resistance to further sliding movement.
[0075] Preferably the leg or legs that include the cranked end
further include a leg section that is formed to increase the
flexibility of the leg.
[0076] The leg section reduces the force required to push the clip
over the connector to locate the clip on the connector section and
makes it possible to control the bending stresses in the legs,
thereby preventing yielding of the legs. Yielding of the legs is
unsatisfactory because it prevents good engagement of the clip onto
the connector.
[0077] Preferably the leg section is in the form of a curved bend
in the leg outwardly of the cranked end.
[0078] Preferably the inner ends of the legs are relatively wide to
enable the legs to grip the connector section securely.
[0079] Preferably the inner ends of the legs include projections
that enable the legs to grip the connector section securely.
[0080] Preferably the legs are formed from spring steel.
[0081] Preferably the legs are formed so as to minimise
interference to concrete flowing into the volume defined by the
connector element that enclose the connector.
[0082] Preferably the means for coupling the clip to the section of
the connector element includes a plurality of clasps that can clip
onto the upper section of the connector element.
[0083] The applicant has realised that it is possible to integrally
form the above-described connector element and clip as a connector
element assembly and that considerable advantages can be achieved
with this combination.
[0084] Accordingly, the present invention also provides a connector
element assembly for use in a connector assembly for connecting
together a concrete body and a structural component wherein the
connector assembly is capable of resisting shear forces between the
structural component and the concrete body.
[0085] The connector assembly includes the connector element
assembly and a connector adapted to be embedded in concrete.
[0086] The connector element assembly of the present invention
includes:
[0087] (a) a barrier section to confine concrete around the
connector, and
[0088] (b) an integrally formed clip section for coupling the
connector element, and more particularly the barrier section, to
the connector.
[0089] Preferably the clip section includes a plurality of legs
formed from resilient material that extend inwardly from an upper
section of the barrier section and have inner ends that describe an
opening that can receive a section of the connector and have a
diameter that is less than that of the connector section, whereby
in use the legs deflect when the connector element is pushed over
the shank so that the shank extends through the opening and the
inner ends of the legs contact the connector section and thereby
couple the connector element to the connector with the barrier
section positioned to surround the connector.
[0090] The above-described connector element assembly can be
effectively locked to the connector. The connector element assembly
can be located on a connector after the connector has been secured,
for example by welding, to a structural component. Alternatively,
the connector element assembly can be located on a connector before
the connector is secured, for example by welding, to a structural
component.
[0091] The connector may be any suitable form of fastener having a
shank with one end adapted to be embedded in concrete. For example,
the connector may be a headed stud or a structural bolt.
[0092] The headed stud may be a two component construction, with a
headed member and a shank member that have complementary
screw-threaded sections that facilitate connecting the members
together. This arrangement facilitates locating the connector
element assembly on the connector. Specifically, with this
arrangement, the connector element assembly can be conveniently
located on the shank member when the shank member is disconnected
from the headed member by sliding the assembly along the length of
the shank member and thereafter connecting the headed member to the
shank member.
[0093] Preferably the legs are formed so that the legs can flex in
one direction, when in use the connector element is pushed over the
connector to locate the connector element on the connector.
[0094] Preferably the legs are formed so that the legs can flex in
two mutually perpendicular directions, when in use the connector
element is pushed downwardly over the shank to locate the connector
element on the connector.
[0095] Preferably at least one of the legs includes an upward
crank.
[0096] The cranked end facilitates guiding the connector element
onto the connector.
[0097] In addition, the cranked end facilitates initially locating
the connector element in the correct orientation in relation to the
connector section. Specifically, the cranked end provides an
obvious visual indication of the correct orientation of the
connector element, and more particularly the clip section of the
connector element, in relation to the connector section.
[0098] In addition, the cranked end increases resistance to sliding
movement of the connector element after it has been located on the
connector section. Specifically, sliding movement tends to cause
the upwardly cranked end or ends to dig into the connector section
and thereby increase resistance to further sliding movement.
[0099] Preferably the leg or legs that include the cranked end
further include a first leg section that is formed to increase the
flexibility of the leg.
[0100] The first leg section reduces the downward force required to
push the connector element over the connector to locate the
connector element on the connector section and makes it possible to
control the bending stresses in the legs, thereby preventing
yielding of the legs. Yielding of the legs is unsatisfactory
because it prevents good engagement of the connector element, and
more particularly the clip section of the connector element, onto
the connector.
[0101] Preferably the leg section is in the form of a curved bend
in the leg outwardly of the cranked end.
[0102] Preferably the inner ends of the legs are relatively wide to
enable the legs to grip the connector section securely.
[0103] Preferably the inner ends of the legs include projections
that enable the legs to grip the shank securely.
[0104] Preferably the legs are formed from spring steel.
[0105] Preferably the legs are formed so as to minimise
interference to concrete flowing into the volume defined by the
connector element that enclose the connector.
[0106] Preferably the opening is a circular opening.
[0107] According to the present invention there is also provided a
method of manufacturing the above-described connector element
assembly that includes stamping a flat blank from a steel sheet,
the blank having (a) a rectangular section that corresponds to the
barrier section and (b) 4 elongate members extending from one side
of the rectangle that correspond to the legs of the clip section,
folding the rectangular section of the blank to form the barrier
section, and shaping the elongate members to form the legs of the
clip section.
[0108] According to the present invention there is also provided a
method of manufacturing the above-described connector element
assembly that includes pressing a cup-shaped member from a steel
sheet, the cup-shaped member having a cylindrical wall that forms
the barrier section, and stamping the base to form the legs of the
clip section.
BRIEF DESCRIPTION OF THE DRAWINGS
[0109] The present invention is described further by way of example
with reference to the accompanying drawings by which:
[0110] FIG. 1 illustrates a conventional composite structure in a
building construction;
[0111] FIG. 2A is an illustration showing the problems associated
with the prior art composite beams;
[0112] FIG. 2B illustrates problems associated with another prior
art composite structure;
[0113] FIG. 3 is a perspective view of a connector assembly
according to an embodiment of the present invention;
[0114] FIG. 4 is a side sectional view of the connector assembly
shown in FIG. 3;
[0115] FIG. 5 is another side sectional view of the connector
assembly shown in FIG. 3;
[0116] FIG. 6 is a side view of an embodiment of a connector
assembly in accordance with the invention incorporating a
restraining clip;
[0117] FIG. 7 is a sectional plan view of FIG. 6 taken along line
7-7;
[0118] FIG. 8 is a perspective view of the connector assembly shown
in FIG. 3 with reinforcing rods;
[0119] FIG. 9 is a graph showing results of a first test involving
prior art;
[0120] FIG. 10 is a graph showing results of the same test as FIG.
9 but incorporating the present invention;
[0121] FIG. 11 is a graph showing results from a second test
involving the present invention;
[0122] FIG. 12 is a vertical cross-section through an embodiment of
a clip in accordance with the present invention coupled to a
connector element;
[0123] FIG. 13 is a top plan view of the clip and the connector
element shown in FIG. 12;
[0124] FIG. 14 is a vertical cross-section through an embodiment of
a connector element assembly in accordance with the present
invention, the Figure also showing in outline a connector and
illustrating the position of the connector element assembly in
relation to the connector in use of these components as a connector
assembly; and
[0125] FIG. 15 is a top plan view of the connector element shown in
FIG. 14.
DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
[0126] A connector assembly illustrated in the Figures includes
shear connector element 10 and a connector in the form of a
fastener that connects the components of a concrete composite
structure. The connector element increases the ductility and shear
strength, and therefore the shear resistance, of a fastener in a
concrete composite structure by surrounding the fastener in the
form of a barrier thereby confining the concrete around the
fastener. In a preferred embodiment, which is the main embodiment
described herein, the connector element surrounds a connector in
the form of a stud that is mounted upright on decking in a
composite concrete beam. However, it is understood that the present
connector assembly could apply to any composite structure involving
the connection of a component to concrete using connectors embedded
in the concrete.
[0127] FIG. 3 illustrates a standard shear connector stud 11 welded
through ribbed decking 12, either directly or through a pre-punched
hole, to a secondary steel beam 13. A shear connector element 10
surrounds stud 11. FIG. 4 is a side sectional view of FIG. 3 but
with the stud 11 and element 10 embedded in a bed of concrete 14.
The shear connector element 10 sits on the pan 22 of the decking
and forms a barrier surrounding the stud. More specifically, the
barrier surrounds the base of the stud shank. In the preferred
embodiment the decking is a steel ribbed decking, either directly
or through a pre-punched hole, and the stud is welded through the
decking to the steel beam underneath.
[0128] When concrete is poured onto the decking to cover the stud
11 and element 10 it flows into a pocket 15 defined by the area
enclosed by the element 10 and totally embeds both the stud and
element in concrete. Placing the barrier element 10 around the stud
11 has the effect of confining the concrete around the base of the
stud and preventing concrete from escaping the element confines.
Accordingly, the base of the stud is securely confined regardless
of the formation of cracks or wedges that would otherwise dislodge
concrete from around the stud base.
[0129] In the embodiment shown, the connector element 10 is an
annular steel ring spaced approximately 38 mm from the axial centre
of the stud. However, the element 10 need not be a solid annular
barrier but can be an element forming a barrier with other
characteristics and shapes. For example, the element may be an
annular mesh or grid element surrounding the stud which, while
still effective in confining the concrete around the base of the
stud, also provides the wet concrete access to the pocket 15 to
more quickly and thoroughly fill the pocket by allowing the wet
concrete to flow through the holes in the mesh barrier. Similarly,
the element could consist of a spiral coil surrounding the stud and
having windings of a sufficiently small pitch so as to provide a
confining barrier but still allow concrete to flow in between the
windings. Elements made of steel are convenient, economical and
relatively simple to use, however elements made of other materials
capable of forming suitable barriers are also envisaged. For
example, other materials that could be used are high-strength
plastic or composite materials that do not chemically react with
the concrete. In the preferred embodiment the elements are steel
rings, that are cut from a length of steel tubing.
[0130] In the embodiment illustrated in FIG. 5 the base of the
annular ring element is cut to accommodate interconnection lips or
joints. Similarly, the element can be modified to accommodate other
features of the decking such as low ribs.
[0131] To keep the elements centrally in position before the
concrete is poured, a holding or restraining clip 30 illustrated in
FIGS. 6 and 7 is located on the top rim 21 of the element 10. The
restraining clip is similar in principle to a circlip but instead
has three arms 31 substantially equally separated from each other
extending outwardly from a semi-circular centre 32. Centre 32 clips
around the shank 16 of stud 11 and the three arms 31 extend towards
the top rim 21 of the connector element 10 and clip onto the rim 21
by way of clasps 33 at the end of each arm 31. The retaining clip
is resilient such that the arms 31 are able to maintain the
connector element 10 a spaced distance from the stud 11 but allow
some amount of flexibility to enable the components to be assembled
and to withstand the forces of the moving wet concrete during
casting. In an alternate embodiment, the restraining clip only has
two opposed arms extending from a semi-circular centre. The clip is
likely to be made of a resilient plastic. As illustrated in FIG. 6
the circular centre 32 of the clip 30 is placed higher on the stud
shank 16 than the top of the element 10 with the arms extending
downwardly onto the rim 21 to in effect hold the element 10 down so
that it does not displace during pouring of concrete. It is
understood that the retaining clip is not the only means of holding
the element around the stud and that any mechanical equivalent
could work equally as well to maintain the element in the correct
position before and during casting. A further embodiment of the
holding means is described in relation to FIGS. 12 and 13.
[0132] Bursting stresses develop in the concrete at studs or
fasteners under high shear force that can cause a vertical
splitting crack to form between the stud and the void, that is, the
crack forms perpendicular to the void 26 shown in FIG. 4. This may
occur before the formation of a wedge in the concrete as shown in
FIG. 4. Therefore, placing a reinforcing bar across the crack
caused by the bursting stresses assists in resisting formation of a
wedge. FIG. 8 illustrates two reinforcing rods 35 held parallel to
ribs 20 on decking 12 by cross plates 36 attached laterally to
connector element 10 on opposing sides of the element. FIG. 4
illustrates the rods in cross-section. Cross plates 36 are welded
to the connector element and contain apertures 37 through which the
reinforcing rods 35 extend and are held in place. The orientation
of the reinforcing rods 35 is such that when embedded in concrete
they traverse a bursted seam that may form and by extending into
more solid concrete the rods anchor the concrete around the stud
11. Maximum effect is achieved by placing the rods deep into where
the wedge will form and reasonably close to the web 23 of the
rib.
[0133] The reinforcing rods are one way of assisting to increase
the holding strength of the present connector assembly.
Additionally, the head 17 of the stud 11 should be fully embedded
in the concrete cover slab above the decking ribs. The relative
height of the stud 11 to the top of the decking ribs 20 also
affects the strength of the connector assembly. It has been found
that a stud having a height of at least 40 mm above the top of the
ribs 20 has improved its performance. Furthermore, increasing the
height of the element 10 to the height of the rib can improve the
performance to that of a shear connector in a solid slab without
voids.
[0134] Stud performance was tested using studs having a height of
95 mm welded through steel ribbed decking with ribs having a height
of 55 mm. FIG. 4 illustrates the set up of a first test with and
without an element 10. In the first test a connector element 10
having a height of 40 mm and clipped to the stud 11 was found to
perform satisfactorily in confining the concrete around the base of
the stud. Accordingly, an element height of at least 70% of the
height of decking ribs 20 will sufficiently confine the concrete
and prevent wedges or cracks entering the pocket 15 from above the
top rim 21 of the element 10. As mentioned above, an even better
performance is achieved where the height of the element equals or
exceeds that of the ribs. Whilst an element height of 20 mm was
found to offer some improvement, it did not perform as well as the
40 mm high element tested. Logically the higher the element forming
the barrier up to a height reaching the height of the rib, the
better the performance of the stud. The steel ring of the tested
element had an outer diameter of 76 mm and a wall thickness of 2
mm.
[0135] Sometimes multiple studs are placed adjacent to each other
on the decking pan 22 to provide increased connection strength. In
this case separate elements 10 may be used to surround each stud
or, alternatively, a single element having a rectangular, oval, or
the like, shape is positioned to surround both studs. Inner
dividing walls of the element in these situations may be provided
to compartmentalise the element giving each stud its own pocket of
locally confined concrete. Hence, when the concrete is poured it
flows into all pockets of the element surrounding the studs. The
element prevents cracks and wedges from forming inside the walls of
the element.
[0136] Tests performed on the single mounted stud and decking
assembly illustrated in FIG. 4 were performed without and with the
barrier element 10 and the results are illustrated in FIGS. 9 and
10 respectively. The shear force acting on the stud was plotted
against the stud slip as defined in FIG. 2. The results provide an
indication of the ductility of the stud and hence its performance
to resist shear force. In FIG. 4 the top shear force travels in the
direction of Arrow SF.
[0137] FIG. 9 illustrates the results of the single mounted stud
welded to the decking substantially equidistant from the webs 23 of
the decking ribs 20, illustrated in FIG. 4 but without the
connector element 10 or bars 35. The graph of FIG. 9 shows that at
the standard 6 mm slip the shear force on the stud was
approximately 53 kN. Another important point is that there is a
substantial drop off of load below the peak level at a slip of
approximately 2 mm and in accordance with some standards the
behaviour is brittle and therefore unsatisfactory.
[0138] In contrast, the same arrangement but with a circumventing
connector element was tested and the results are shown in the graph
of FIG. 10. The shear force at the 6 mm slip mark was remarkably
higher at 81 kN, almost a 53% improvement on the stud without the
element. In addition, the graph indicates that there is no
substantial drop off of load after the peak load, thereby
indicating that the behaviour is ductile and therefore
satisfactory.
[0139] The element used in the above tests was 40 mm in height and
surrounded a 95 mm high stud with its centre located 68 mm from the
base of the rib web 23 at which a wedge would form. The stud was
welded equidistant between the right-side rib 25 and left-side rib
24, which calculates to be 68 mm from the base of the web of the
right-side rib 25.
[0140] It has been found that shear strength of studs significantly
improves if the distance of the studs to the active rib webs 23 are
increased. For example, FIG. 5 illustrates a stud located closer to
the left-side rib 24 than the right-side rib 25. With the top shear
force travelling in the direction of Arrow SF a wedge is likely to
form at the right-side rib 25. Hence, moving the stud further away
from this rib 25 increases the size of the wedge of concrete that
has to be dislodged around the base of a stud. Combining the
increased distance between the stud and active rib with the use of
the present connector element can significantly increase the shear
strength and ductility of the stud. The graph of FIG. 11 shows the
results of a shear force verses slip test of a stud located 100 mm
away from the right-side rib 25 as illustrated in FIG. 5. The stud
is surrounded by a connector element 40 mm in height. The graph
results show that at the 6 mm slip mark the stud sustained a force
of approximately 115 kN and finally fractured just under 120 kN,
which is an extremely favourable performance as if the stud had
been in a solid concrete slab without voids.
[0141] However, this optimal performance is also achievable with a
higher connector element 10 or a higher stud 11 and with the stud
closer to the rib.
[0142] It is noted that all of the examples and tests described
herein involve longitudinal shear force in secondary composite
beams, which sustain the most damage, where the beams are in
positive bending. However, it is noted that failure is also likely
in secondary composite beams where longitudinal forces develop in
regions of negative moments.
[0143] The advantage of placing the present connector element
around the stud to form a connector assembly and encapsulate and
localise concrete at the stud base, as shown in FIGS. 3 and 4,
produces significant and important increases in strength and
ductility of the studs, and on the whole make them more robust.
This in turn translates to a composite structure where the major
problem of rib punch-through failure is significantly reduced or
entirely avoided. Additionally, the number of connector assemblies
required in composite structures can be reduced on account of the
increased strength which leads to shorter installation time and
less material. With the present connector assembly the composite
concrete structure is able to withstand a much higher ultimate load
and, with its increased structural integrity, provide a more
reliable and more economical construction.
[0144] FIGS. 12 and 13 illustrate an embodiment of a clip for
holding a connector element 3 in relation to a connector.
[0145] The connector element 3 shown in FIG. 12 forms part of a
connector assembly of the type disclosed in FIGS. 3 and 4.
[0146] The connector element 3 is in the form of a steel ring that
has an upper rim 5.
[0147] Whilst not shown, the connector assembly also includes a
connector in the form of a fastener that has a shank and an
enlarged head that connects a component such as a steel column to
an underlying foundation prior to pouring concrete into the
foundation. In this application the connector element 3 increases
the ductility and shear strength, and therefore the shear
resistance, of the fastener by forming a barrier around the
connector and thereby confining concrete around the fastener.
[0148] The purpose of the clip, generally identified by the numeral
7, in FIGS. 12 and 13 is to facilitate locating the connector
element 3 securely in place in relation to the connector before
concrete is poured. In order to achieve this objective, the clip 7
is located first on the connector element 3 and the assembly of the
connector element 3 and the clip 7 are located on the shank by
positioning the clip above the shank and then pushing the clip down
onto the shank.
[0149] The clip 3 includes a circular outer frame 9. The frame 9
includes an inner circular wall 11 that has a diameter that enables
the wall to contact an inner surface of the connector element 3
when the clip 7 is coupled to the connector element 3. The wall
provides stability to the assembly of the connector element 3 and
the clip 7.
[0150] The clip 3 shown in FIGS. 12 and 13 also includes 2 pairs of
outer clasps 13 that can be located over the rim 5 of the connector
element 3 and couple the clip 7 securely to the connector element
3.
[0151] The clip 7 also includes 4 equally spaced legs 15 extending
inwardly from the frame 9.
[0152] The legs 15 are formed from spring steel. The legs 15
terminate in inner ends 17 that describe a circular opening 19 for
receiving the shank of the connector. As described above, the
diameter of the described opening 19 is selected to be less that
that of the shank so that the legs 15 engage and thereby couple the
clip to the connector when the clip is pushed down onto the
shank.
[0153] The legs include upwardly inclined sections 21 that define a
frusto-conical region around the shank. As is described above,
these upwardly cranked sections provide a number of advantages,
including facilitating guiding the clip onto the shank,
facilitating initially locating the clip in the correct orientation
in relation to the shank, and increasing resistance to upward
movement of the clip after it has been located on the shank.
[0154] The connector element assembly shown in FIGS. 14 and 15 is
intended for use as part of a connector assembly of the type shown
in FIGS. 3 and 4 for connecting a component such as a steel column
to an underlying foundation prior to pouring concrete into the
foundation. In addition to the connector element assembly, the
connector assembly also includes a connector 4 (partly shown in
outline in FIG. 14) in the form of a fastener that has a shank (as
shown in the Figure) and an enlarged head at the top (not shown).
In this application the purpose of the connector element assembly
is to increase the ductility and shear strength, and therefore the
shear resistance, of the connector 4 by forming a barrier around
and thereby confining concrete around the connector 4.
[0155] The connector element assembly shown in FIGS. 14 and 15
includes (a) a barrier section 5 and (b) a clip section generally
identified by the numeral 7.
[0156] The purpose of the barrier section 5 is to confine concrete
around the connector 4.
[0157] The purpose of the clip section 7 is to facilitate locating
the connector element assembly securely in place in relation to the
connector 4 before concrete is poured.
[0158] The barrier section 5 is in the form of a cylinder or
ring.
[0159] The clip section 7 includes 4 equally spaced legs 15
extending inwardly from the barrier section 5.
[0160] The legs 15 terminate in inner ends 17 that describe a
circular opening 19 for receiving the shank of the connector. The
diameter of the described opening 19 is selected to be less that
that of the shank so that the legs 15 can engage and thereby couple
the connector element assembly to the connector 4 when the
connector element assembly is positioned onto the shank as shown in
FIG. 14.
[0161] The legs 15 include upwardly inclined sections 21 that
define a frusto-conical region around the shank. As is described
above, these upwardly cranked sections provide a number of
advantages, including facilitating guiding the connector element
assembly onto the shank, facilitating initially locating the
connector element assembly in the correct orientation in relation
to the shank, and increasing resistance to upward movement of the
connector element assembly after it has been located on the
shank.
[0162] The legs 15 also include a downwardly-curved bend 25 between
the frusto-conical region and the junction of the legs 15 and the
barrier section 5. The bends 25 increase the effective length of
the legs 15.
[0163] In use, the connector element assembly is located on the
shank of the connector 4 by positioning the clip section 7 above
the shank with the legs 21 contacting the head (not shown) of the
shank and then pushing the connector element assembly down onto the
shank.
[0164] One option for manufacturing the connector element assembly
is to form the connector element assembly from one piece of flat
steel sheet. The first step is to stamp a flat blank from the steel
sheet, with the blank having (a) a rectangular section (that
corresponds to the barrier section 5), and (b) 4 elongate members
extending from one side of the rectangle (that correspond to the
legs 15 of the clip section 7). The next step is to roll the
rectangular section into a cylinder and to join the ends of the
rectangle together. The ends could be joined together by means of
hook elements 23 formed at one end that are either passed through
openings (not shown) formed at the other end of the rectangle and
are then folded back onto the cylinder or by double folding the
ends onto each other which has the advantage of not reducing the
steel section. Another, although not the only other, option is to
weld the ends together. The final step is to shape the legs 15 into
the required configuration, as shown in FIG. 14.
[0165] Another option for manufacturing the connector element
assembly is to press a cup having a base and a cylindrical wall
from one piece of flat steel sheet, thereafter stamp the base to
form an outline of the legs, and finally shape the legs to the form
shown in FIG. 14.
[0166] In both of the above-described options, the formed connected
elements are heat treated to form high-tensile spring steel.
[0167] It will be understood by a person skilled in the art of the
present invention that many modifications may be made without
departing from the spirit and scope of the present invention.
[0168] By way of example, whilst the embodiments shown in FIGS. 12
to 15 include 4 legs, the present invention is not so limited and
extends to clips and connector elements that have any suitable
number of legs.
[0169] In addition, whilst the embodiments shown in FIGS. 12 to 15
include radially extending legs, the present invention is not so
limited and extends to legs that are not radial legs.
[0170] In addition, whilst the embodiments shown in FIGS. 12 to 15
include upwardly inclined sections that define a frusto-conical
region around the shank, the present invention is not so
limited.
[0171] In addition, whilst the embodiments shown in the Figures are
described in the context of composite concrete structure that
includes a decking sheet and a layer of concrete on the sheet and
connecting the composite concrete structure to an underlying
structural component, the present invention is not so limited and
extends to concrete structures generally. For example, the present
invention extends to connector assemblies that can be used in
relation to concrete footings and the like that are used to support
steel columns with base plates and other structural components.
These arrangements typically include connectors in the form of
bolts that are embedded in concrete footings and extend from the
footings and provide connection points for base plates. In such
arrangements, with reference to FIG. 2B, the connector assemblies
would be fitted upside down underneath the steel base plate on
bolts nearest the free edge.
[0172] Whilst the embodiments shown in the drawings relate to
arrangements in which the connectors extend vertically in use from
an underlying support structure, the present invention is not so
limited and extends to other arrangements, for example,
arrangements in which the connectors extend horizontally in a
concrete body. One specific example of such arrangements includes
connectors in the form of headed studs that are welded to an
upstanding web of a T-section support structure at spaced intervals
along the length of the web and extend horizontally into a concrete
body. With this particular arrangement, the connector elements are
positioned around the horiztonally extending studs.
[0173] Whilst the embodiments shown in the drawings relate to
arrangements in which the connector elements contact decking
sheets, the present invention is not so limited and extends to
arrangements in which the connector elements are spaced above
decking sheets and thereby allow wet concrete to flow in the gap
between the decking sheets and the connector elements.
[0174] Furthermore, whilst the discussion of the present invention
focuses on applied loads in a particular direction, the present
invention is equally applicable to arrangements that are subjected
to varying loads in one or more directions.
* * * * *