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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates generally to a formwork or shuttering
assembly for the encased concrete construction system.
One known form of such an assembly is made up of side walls and optionally
end walls, to be disposed at the appropriate locations, wherein the walls
are provided at their edges with grooves and projections which are capable
of interengaging for securing the walls in position relative to each
other, with the side walls being connected together by bars or tie
members. The walls comprise for example a hard plastic foam material. A
largescale assembly of that nature, as disclosed for example in German
published specification (DE-AS) No. 26 18 215, may be used in many
situations and permit buildings to be erected quickly and at low cost,
while also providing good external and internal thermal insulation, with
the side walls thus acting as a form of cladding.
However, various disadvantages are often found with the known forms of such
assemblies, more particularly having regard to the wide range of
requirements which are to be made in respect thereof. For example, where
the connecting bars or tie members comprise for example a hard foam, being
produced in one piece with the side walls for example, there is the
possibility of fire striking through the wall along the tie members. On
the other hand, in such an assembly as disclosed for example in U.S. Pat.
No. 4,223,501, the tie members are in the form of metal grid or lattice
members or sheet metal members which are fitted into the mould during
manufacture of the assembly. That is a difficult and complicated
operation, while also giving rise to what are known as cold bridges
through the wall, because the metal members, in order to provide a secure
anchoring action, terminate comparatively close to the outside surface of
the wall built with the assemblies. In an assembly as disclosed in U.S.
Pat. No. 3,788,020, the tie members are in the form of sheet metal members
which are subsequently fitted into pre-formed slots or grooves in the side
walls of the assembly, which results in the side walls being considerably
weakened due to the provision of the slots or grooves, while also
permitting the formation of cold bridges.
There are therefore a number of aspects in which improvement in the
above-discussed assemblies would be desirable, while nonetheless the
assemblies remain strong and stable, having regard to the concrete filling
which is introduced thereinto and which may frequently extend over the
height of a complete story, as well as being capable of resisting internal
and external loadings applied thereto and providing inexpensive
manufacture and easy transportation by virtue of not taking up a great
deal of space.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a formwork or shuttering
assembly for concrete construction systems, which at least substantially
overcomes difficulties and disadvantages encountered in the prior-art
arrangements.
Another object of the present invention is to provide a formwork assembly
which can be used in a wide range of different situations and which
permits ready adaptation thereto.
Yet another object of the present invention is to provide a formwork
assembly which can be produced at relatively low cost with short
manufacturing cycle times while being capable of withstanding high levels
of loading, more particularly when being filled with concrete.
A further object of the present invention is to provide such an assembly
which also permits use thereof as heat barrier or insulation plates or
panels for different situations of use.
Still a further object of the present invention is to provide a formwork
assembly which takes up a comparatively small amount of space in regard to
transportation and storage thereof.
These and other objects are achieved by means of an assembly in accordance
with the principles of this invention, comprising side wall portions
having grooves and projections at respective edges thereof for positional
securing thereof relative to other such side wall portions. In the
assembled condition, the side wall portions are interconnected by
connecting means such as bars or like tie members, and the side wall
portions may also optionally be interconnected by end wall portions at the
appropriate locations.
Each side wall portion is provided on its inwardly facing surface, being
therefore the surface which faces towards another side wall portion in the
assembled condition thereof, with engagement means engageable by suitable
engagement means provided on the tie members, to secure the components in
the appropriate relative positions.
As will be seen in greater detail hereinafter, the construction in
accordance with the invention as set forth in broad terms above permits
the side walls and the tie members to be produced separately and thus
possibly from different materials. That means that the manufacturing
moulds are simpler and less expensive, and permits short manufacturing
cycle times. The material used for the tie members may be a material which
has a high degree of strength and resistance to heat, for example
reinforced concrete, so that the side walls withstand a high internal
pressure within the assembly when the concrete is being introduced
thereinto. That construction at least substantially eliminates the danger
of fire striking through the concrete wall, in contrast to the
above-discussed tie members which comprise for example hard foam and which
are produced in one piece with the side wall portions. Furthermore, the
storage and transportation expenditure remains at a low level because the
individual components can be left in a disassembled condition until they
reach the building site or possibly for example a regional storage centre,
when they can be readily assembled to put them into a condition for use.
That is also in contrast with the assembly discussed above wherein the tie
members are in the form of metal grid or lattice members or sheet metal
members which are incorproated into the side wall portions in the course
of manufacture thereof, which means that the assembly, being produced in
the ready-for-use form, is bulky and cumbersome.
In addition, the material used for the tie members may be such as to
substantially eliminate the risk of acoustic bridges, so that the need for
sound-proofing materials on the constructions which are built with the
assembly according to the present invention can be at least substantially
reduced.
The side wall portions, tie members and end or intermediate wall portions,
as well as the way in which those components are suitably secured together
to constitute the final assembly, may be the subject of many different
variations. Thus, in a preferred embodiment of the invention, the
engagement means on the side wall portions are formed by a shallow
depression or recess of a cross-section providing undercut edges, while
the tie member comprises a co-operating portion which is of a
corresponding configuration so that it can be brought into retaining
engagement therewiht. Conversely, the engagement means on the side wall
portions may also be formed by a shallow raised portion of a cross-section
such as to provide an undercut edge configuration, on to which a
co-operating portion on the tie member, of suitable configuration, may be
brought into latching engagement. Thus, that arrangement provide a form of
snap-in or snap-on or clipping connection between the side wall portion on
the one hand and the tie member or other like component on the other hand,
the undercut edge configurations ensuring that the two components being
joined together are drawn towards each other by the wedge-like action of
the undercut edge configuration. In addition, an adhesive may be applied,
as by spraying, before the components are brought into the engaged
condition. The depression or the raised portion referred to above may be
comparatively shallow, being for example from 2 to 5 mm in depth or height
respectively, so that there is virtually no weakening of the side wall
portions. The actual configuration of the depression or raised portion,
and the corresponding co-operating part of the tie member, may be adapted
to the respective conditions involved. However, a circular shape has been
found to be particularly desirable, although it is also possible for the
depression to be for example in the form of a groove of dovetail-shaped
cross-section, and similarly in regard to the raised portion or
projection. With such an arrangement, one or more grooves or raised
portions or projections may extend in a continuous manner to the upper
edge and/or to the lower edge of the side wall portion, whereby the
corresponding co-operating part of the tie member can be readily fitted
thereinto. The exposed parts of the grooves or projections, which are
therefore not occupied by the co-operating part of the tie member, provide
an additional anchoring action by increasing the engagement between the
side walls and the concrete which is poured into the formwork assembly,
without the need to take any particular steps in that respect, such as
forming further depressions or recesses in the internal surfaces of the
side wall portions. It will also be appreciated that the junction between
the side wall portions and the tie members is still firmly maintained even
if for example an adhesive joint therebetween is no longer in a good
condition, by virtue of the positive interengagement between the side wall
portions and the tie members. For the purposes of correct positioning of
the tie members or other like members, the groove or the projection on the
side wall portion may be provided with suitable centering means.
In another advantageous embodiment of the invention, it is provided that
the side wall portions and the tie member or like connector are
interconnected by the interengagement of a ball portion provided on one
component and a ball-receiving socket in the other component. The ball or
the ball-receiving socket may be disposed on a raised portion on the
respective component or at the bottom of a depression or recess in the
respective component, such raised portion or recess preferably being of a
circular configuration. In the case of a construction in which the tie
members have respective contact surfaces at each of their two ends, such
surfaces being formed as counterparts to the raised portion or depression
on the respective side wall portion and/or the ball or ball-receiving
socket respectively, it is possible for the surfaces which come into
contact with each other in that way to be additionally secured together as
by adhesive, over a substantial surface area, thus enhancing the
connection therebetween. In that arrangement the ball portion and the
socket in which it is received are desirably of such a configuration that,
after they have been fitted together, there is a certain amount of tensile
loading therebetween, which thus urges the co-operating surfaces more
firmly into contact with each other and enhancing the adhesive join
therebetween. In order further to increase the area of the surface
available for making the adhesive join, the above-mentioned contact
surfaces may be provided with enlargement portions which extend beyond the
co-operating parts of the respecitve side wall portion and tie member.
In accordance with another development of the invention, the engagement
means on a side wall portion may be formed by substantially equally
spaced-apart grooves which extend from top to bottom of the respective
side wall portion and which are distributed over the whole of the inside
surface thereof. The grooves may be of square or rectangular cross-section
or they may be of such a configuration that they are enlarged at their
bottom, being for example in the form of a dovetail-shaped cross-section.
An assembly which is made up of side wall portions of such a nature may be
readily produced in virtually any desired length, or may be cut to the
desired dimension, as required, by virture of the grooves extending
continuously over the inside surface of the side wall portion and thus
affording a ready form of adjustability in regard to relative positioning
of the side wall portion and the tie member or members to be associated
therewith. The grooves further enhance the interengagement between the
side wall portions and the concrete introduced therewithin, thereby at
least impeding the penetration of water into any gap between the side wall
portion and the concrete, while in addition avoiding the possibility of
noise being produced by virtue of the side wall portion flapping or
striking against the concrete when set, by virture of the side wall
portion being held securely against the concrete. Between each two grooves
is formed a respective raised portion or land, the cross-section of which
is advantageously complementary to the cross-section of the grooves. The
resulting stepped or castellated configuration of the internal surface of
the side wall portion has a shock-absorbing action when the concrete is
being poured thereinto, in which respect it should be appreciated that the
concrete often drops into the assembly formed by the side wall portions
and the corresponding tie members, from a comparatively great height. In
that case, individual lumps of concrete tend to be broken up by hitting
the internal surface of the side wall portions, and do not impact against
the side wall portions sufficiently to cause the assembly to be damaged or
destroyed.
The side wall portions may preferably comprise a hard foam material,
although it is also possible to use other materials. More particularly, it
is possible for side wall portions of different natures to be joined
together in the same assembly. For example, a hard foam side wall portion
may be used on the outward side of the wall of a building, while a gypsum
fibre panel may be used on the inward side. Other combinations, including
using mineral insulating substances, are also possible.
The material used for the tie members is desirably such that, while giving
a good and strong connection, it at least substantially eliminates the
fear of fire striking through the wall. In an embodiment of the invention,
the tie members comprise concrete at least in the region of their surfaces
which bear against the respective side wall portions. A heavy concrete
(vermiculite) is also particularly suitable in this case. When securing
for example hard foam and concrete together as by adhesive, substantially
shorter setting times are required than when using adhesive to join two
hard foam components together, because the solvent can more quickly escape
from the adhesive join. In order to enhance their tensile strength, the
tie members may be provided in their middle region with one or more
reinforcing bars which are either free or exposed or have concrete cast
therearound. In a preferred embodiment, the tie members which comprise
concrete also have coaxial holes or bores which extend thereinto from both
ends and which terminate at a small spacing from each other. The portion
of concrete which thus remains between the mutually adjoining ends of the
two bores in each tie member eliminate the fear of fire striking through
the tie member, but the remaining portion of concrete can also be easily
drilled through at a later stage, for example for easily fitting fixing or
support members or for passing pipes or other conduits therethrough. The
operation of finding the correct location for that operation is
particularly simplified when the side wall portions are provided with
centering points or marking on their outside surface, thus identifying the
positions of the tie members and possibly the bores or holes therein.
Tie members which are made in one piece from concrete are provided at both
ends with plate-like end portions which are connected together by way of a
central shaft portion. The end plate portions are desirably of circular
shape but they may also be of other shapes such as oval, square,
rectangular or the like. The shaft portion may have at least one
peripheral groove at its transition to the respective end plate portions.
Reinforcing bars may be fitted into such a groove in the proper relative
position. Two adjacent grooves permit the reinforcing bars to be disposed
in a mutually crossing relationship.
The contact surfaces of the connecting or tie members are desirably formed
with a counterpart configuration relative to the engagement means on the
side wall portions in order to provide a good and firm connection
therebetween. As will be described in greater detail hereinafter with
referece to a specific embodiment, the engagement means on the side wall
portions may be formed by at least substantially equally spaced-apart
grooves which extend from top to bottom of the respective side wall
portion and which are distributed over the entire inside surface thereof;
in that configuration, the contact surfaces on the end plate portions of
each tie member are of a suitably matching shape, with grooves and
projections disposed in an alternate array. Even if the grooves for
example in the side wall portions are of an undercut configuration, the
corresponding projections on the end plate portions of the tie members may
be of square or rectangular configuration so that they can be easily
fitted into such grooves, a high level of strength in the connection
between the tie member and the respective side wall portion being achieved
by virtue of an adhesive join being formed over a substantial surface
area. By virtue of the continuous nature of the grooves in the side wall
portions, the tie members can be mounted thereto in the respectively
desired position and at the respectively desired height, simply by virtue
of being slid along the appropriate groove to the appropriate height. When
the end plate portions are mounted to the respective side wall portion in
such a way that they bridge over the vertical or horizontal gap between
formwork assemblies, they also serve at the same time for connecting
adjacent assemblies together. A plurality of such assemblies may be joined
together at the same time at the point of meeting as between a horizontal
and a vertical gap.
The tie members may also be in the form of two plate portions which form
the surfaces for contacting the respective side wall portions, with the
plate portions being suitably connected together for example by way of tie
struts in the form of wires or flat elements, preferably disposed in
mutually crossed configuration. In that respect, it may be important to
produce a certain spring effect which helps to avoid the side wall
portions being subjected to an abrupt loading when the concrete is being
poured into the assembly, thereby to ensure that the tie members are not
torn out of the side wall portions.
In order to enhance the adhesion between the side wall portions and the
concrete once it has set, a development of the invention provides that the
side wall portions may be provided on their internal surface with
channel-like recesses or elongate raised portions which preferably extend
parallel to the narrow sides of the side wall portions. Raised portions
may be used more particularly when the engagement means on the side wall
portions comprise raised portions co-operable with the appropriate tie
members, as in the way the thickness of the side wall portions and thus
the amount of space required for transportation and storage is not
additionally increased. When the engagement means on the side wall
portions comprise depressions or recesses, then channel-like depressions
are preferably also provided on the side wall portions to enhance the
adhesion between them and the concrete. In addition, the side wall
portions may be provided on their outward surfaces with a grid
configuration or pattern which may be of a raised or depressed nature, to
permit parts of the components making up the formwork assembly to be cut
up or in some other way separated, at the precise dimensions required, on
the building site itself. Thus, it is possible to provide a cross grid or
a pattern comprising parallel vertical lines. The depth of the channels or
grooves forming the pattern or the height of the land portions formed
thereby only have to be of such a magnitude as to provide a ready guide
and to be easily located for the operation of cutting the component to
size
The grooves and projections which are provided at the edges of the side
walls portions for securing them together in the correct relative
positions are of an undercut configuration, in accordance with a
particularly advantageous development of the invention, thus giving a
connection between adjacent side walls which is capable of withstanding a
tensile loading therebetween. That applies both in regard to connecting
formwork assemblies which are fitted one upon the other, building
therefore in a vertical direction, and also in regard to the connection
between such assemblies which are disposed side by side, building
therefore horizontally. When such a form of connection is provided, there
is then no longer the risk that, after a wall which extends over the
height of the story has been erected or after an entire story wall has
been built but before concrete is poured thereinto, a strong wind or storm
or like conditions may cause the structure to collapse. The projections
may be of a dovetail-shape crosssection with suitably adapted grooves,
rounded edges on that construction being particularly desirable. It is
also possible for the projections to comprise a first portion which is of
an approximately circular cross-sectional shape and which is connected to
the main body of the side wall portion by way of a short neck or
connecting part. The grooves are then of a complementary configuration. A
rounded structure of that kind has the advantage that any fouling due to
concrete which may for example be left thereon, which may readily occur
under the operating conditions to be found on a building site, can be more
easily removed.
Another embodiment of the invention may also provide that, at their upper
and lower edges, the side wall portions are provided with blind holes of
T-shaped cross-section, with the holes being open towards the inside of
the side wall portions, for retainingly accommodating end plate portions
on suitable tie members. The blind holes may be comparatively close to the
inside surface of the side wall portions so that the latter are not
seriously weakened thereby. The depth of the blind holes may correspond to
half the dimension of the end plate portions on the tie members so that
half of an end plate portion is disposed in one side wall portion while
the other half is in the side wall portion which is disposed directly
thereabove. The end plate portions on the tie members are desirably of a
square configuration and are connected by way of a bar of square or
rectangular cross-section. The tie members can then be turned alternately
through 90.degree. relative to each other, thereby giving a higher degree
of torsional stiffness. The cross-section of the blind holes is then to be
suitably adapted to that arrangement. The end plate portions on the tie
members may comprise for example sheet metal, while the connecting bars
may be welded wires. A further development in that arrangement provides
that two tie members each having two end plate portions are connected in
the region of their connecting bars, between the end plate portions. When
the connecting bars are joined together in that way at their centres, the
result is a X-shaped tie member which again has a certain spring action.
In addition, the distance between each two double tie member assemblies of
that kind, at the centre of the respective wall portion, is increased by
virtue of the X-like configurations, so that pipes or tubes of larger
crosssection, being for example 100 mm in diameter, may be easily pass
therebetween.
Where formwork or shuttering assemblies meet each other in end-to-end
relationship, for example along the major part of a wall to be built,
there is no need for end wall portions or panels at the ends of the
respective assemblies. However, at the corners of a building, at junctions
between outer and inner walls and for example at window openings or door
apertures, the assemblies must be closed off at their ends. Therefore, it
is only at such locations that end wall portions or panels, or
intermediate wall portions, need to be used. The end wall portions may
either be secured in position by adhesive means in a flush abutting
condition, or they may be provided at their side edges which butt against
the side wall portions, with positioning elements co-operable with
corresponding elements of a complementary configuration on or in the side
wall portions. The positioning elements may comprise for example pins,
with associated bores, or grooves with associated projections. When
adhesive is used, it is desirable not to provide any undercut
configuration so that the end or intermediate wall portions can be simply
pressed into place and do not have to be slid or otherwise pushed into
position, for if that were to be the case, the adhesive used would be
pushed off the component as it was slid into the appropriate position.
The assemblies according to the invention may be adapted to virutally any
practical requirements by means of just one kind of side wall portion,
with associated tie members, and just one end wall portion. There is
therefore no need to use special corner comonents and other connecting
elements of various shapes. In addition however it is also possible for
the side wall portions to be used as heat barrier or thermal insulation
panels. Such insulating panels may also be laid as roof insulating panels
on or under the roof joists or rafters. The way in which the panel
portions fit together by positive interengagement permits operation to be
carried out quickly and neatly. The panels may be of comparatively great
length, being for example 2 meters in length, because the formwork
assemblies may also be of a correspondingly large size. In a similar
fashion, the heat insulation panels may be laid on a floating floor and
may possibly carry pipes or tubes of a floor heating system. The heat
insulation panels may also be mounted on the outside or the inside of
buildings.
When using the side wall portions discussed above, wherein the engagement
means are formed by at least substantially equally mutually spaced grooves
which extend from top to bottom and which are distributed over the entire
inside surface of the side wall portions, the grooves thereof are disposed
upwardly and in the direction of fall of the roof when they are employed
as roof insulating panels, so that any water which penetrates into the
grooves or which condenses on the panels can run off to the eaves. When
such side wall portions are used as floor panels on which heating tubes or
pipes are possibly laid, the side bearing the grooves is disposed
downwardly in order to provide for better footstep sound insulation. In
addition, when using gypsum or adhesive mortar, the grooves permit the
side wall portions to be subsequently fitted in position as inside or
outside wall insulation.
For the purposes of securing the thermal insulation panels to a wall to be
insulated thereby, it is also possible to use holders which are of a
configuration approximately corresponding to one end of an above-mentioned
tie member, wherein the holders co-operate with the engagement means on
the side wall portion forming the thermal insulation plate, and can be
secured to the wall. For the purposes of properly positioning the holders,
use is desirably made of a template or jig arrangement. The holders
advantageously have a base portion providing a contact surface with a ball
portion thereon, which is capable of engaging into a ball socket in the
side wall portions. When the side wall portion is used as a thermal
insulation panel for insulating floor heating systems, it is preferable to
use holder means for the pipes or conduits of the floor heating system,
which are of a configuration corresponding to one end of the
above-mentioned tie member and which co-operate with the engagement means
on the side wall portions. For the purposes of securely and easily fixing
the pipes or conduits in position, the holder means may have a ball
portion which is capable of engaging into a ball-receiving socket in the
side wall portion forming the thermal insulation plate and which is joined
to a head portion provided with a bore for receiving the pipe or conduit,
the ball having a slot which extends therethrough and into the bore. With
such an arrangement, the holder can be bent open, by opening the slot, so
that it can be fitted over the pipe or conduit by passing the latter
through the slot, with the holder then being held in the position of being
closed around the pipe or conduit by the ball portion thereof being
engaged into a socket.
When the material used for the assembly according to the invention is a
hard foam, it is preferable to use a fire-retardant hard foam of class F
in order to eliminate the danger of fire.
Further objects, features and advantages of a formwork assembly according
to the present invention will be more clearly apparent from the following
description of preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective view of an embodiment of a formwork or
shuttering assembly according to the invention,
FIG. 2 is a diagrammatic cross-sectional view of part of the assembly in
the region of the junction between tie member and a side wall portion,
FIG. 3 shows a construction which is of a complementary configuration to
that shown in FIG. 2,
FIG. 4 is a view of a modified embodiment of a junction between a tie
member and a side wall portion,
FIG. 5 is a cross-sectional view through an assembly as shown in FIG. 1, in
the region of the tie members,
FIG. 6 shows a modified embodiment of the side wall portion of an assembly,
FIG. 7 shows a sectional view of part of a further embodiment of a tie
member showing the way in which it is fixed in a side wall portion,
FIG. 8 is a perspective view of another embodiment of a side wall portion
of an assembly,
FIG. 9 shows tie members used with the side wall portion shown in FIG. 8,
FIG. 10 shows a view of a further embodiment of a double tie member,
FIG. 11 is a perspective view of an embodiment of an end or intermediate
wall portion,
FIG. 12 is a diagrammatic view in cross-section of part of the arrangement
for securing a thermal insulation panel or plate to a wall to be
insulated,
FIG. 13 is a diagrammatic view of a section of a floor insulating plate or
panel with a floor heating system pipe fixed thereon,
FIG. 14 shows a holder device for securing the pipe of a floor heating
system as shown in FIG. 13,
FIG. 15 shows a further embodiment of an assembly according to the
invention,
FIG. 16 shows a corner connection using assemblies and tie members as shown
in FIG. 15,
FIG. 17 shows a T-shaped junction using assemblies and tie members as shown
in FIG. 15, and
FIG. 18 shows a roof or ceiling termination using assemblies and tie
members as shown in FIG. 15.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring firstly to the perspective view shown in FIG. 1 of an embodiment
of a shuttering or formwork assembly, which may also have a cladding
action as described hereinafter, in accordance with the present invention,
the assembly comprises two side wall portions 10 comprising fire-retardant
hard foam material which are connected together in at least substantially
parallel relationship by way of two connecting members shown as tie
members or bars 11, and an end wall portion 12. For the purposes of
connecting together assemblies of the same nature which are disposed in
side-by-side relationship or in superposed relationship, by a positive
mechanical interengagement, the upper and lower edges as well as the end
edges of the side wall portions 10 and the upper and lower edges of the
end wall portion 12 are provided with projections in the form of elongate
web portions 13 and grooves 14 of a complementary shape. The cross-section
of the projections 13 and the grooves 14 is defined by a circular portion
and a short neck or joining portion adjacent thereto. For the purposes of
fitting the wall portions together, the projections 13 are fitted into the
appropriate grooves 14 as by being slid thereinto.
Provided in the inwardly facing surfaces of the side wall portions 10 are
channel-like recesses or depressions 15 which may possibly also be of an
undercut configuration, being for example of a dovetail-like shape, and
which provide for additionally securing the side wall portions to the
concrete which is poured into and which sets in the assembly defined by
the side and end wall portions. Provided on the outwardly facing surfaces
of the side wall portions 10 are markings in the form of shallow channels
16 which permit the wall portions to be more easily cut up or in some
other way separated at the appropriate dimensions. Reference numeral 17
denotes the marking points which mark the position of the tie members 11.
FIG. 2 shows an embodiment of the engagement means whereby the side wall
portion 10 and a tie member 11 are positively interconnected. As
illustrated, the side wall portion has a shallow recess or depression 18
with an undercut edge configuration, thus defining a generally
dovetail-like cross-section, while the tie member 11 has a base or end
portion 19 with a complementary raised portion or projection 20 which is
also of a complementary configuration, so that it can be fitted into the
recess 18 by a snap-in or clipping action, thereby being held in latching
engagement therein. The configuration of the components is such that after
the tie member has been brought into snap-in engagement with the side wall
portion, there is a certain tensile stress therebetween whereby the tie
member 11 is held in a position of bearing firmly against the wall portion
10. If, before the tie member 11 and the wall portion 10 are fitted
together, the surfaces thereof which come into contact with each other are
sprayed with adhesive, that provides a very secure connection
therebetween, which has a high degree of tensile strength.
FIG. 3 shows an embodiment of the connecting means between the tie member
11 and the side wall portion 10, which is complementary to that shown in
FIG. 2, insofar as the portion 19 of the tie member 11 has the shallow
recess or depression 18 while the wall portion 10 has the corresponding
projection 20.
Reference will now be made to FIG. 4 showing another embodiment of the
connection formed by suitable engagement means between the side wall
portion 10 and the tie member 11. The portion 19 of the tie member 11 has
a central shallow recess 21 while the wall portion 10 is provided with a
corresponding raised portion or projection 22. Disposed in the centre of
the recess 21 is a ball portion 23 which can be latchingly engaged into a
ball-receiving socket 24 by being simply pressed thereinto. In this case
also, after the ball 23 and the socket 24 have been brought into latching
interengagement, there is also a residual tensile stress therebetween so
as to ensure that the components are securely fitted in position and are
firmly secured together by the adhesive. In order better to distribute the
loadings involved and to increase the surface area which can form the
adhesive join, the portion 19 of the connecting member 11 may be provided
with enlargements 25 as indicated in broken lines in FIG. 4.
FIG. 5 shows a view in cross-section through the assembly in FIG. 1. Two
tie members 11 which are disposed one above the other are connected to the
side wall portions 10 by engagement means, as in the embodiment
illustrated in FIG. 2. In the FIG. 5 embodiment, the tie members 11
comprise concrete and have central bores 26 which extend thereinto from
both ends, in coaxial relationship therewith, and which terminate at a
spacing from each other of a few centimetres. The centering points 17 on
the outside of the side wall portions 10 in FIG. 1 mark the positions of
the bores 26 so that the portion of concrete which remains between the
mutually adjacent ends of the bores 26 can be subsequently drilled through
to permit conduits or cables to be passed therethrough, or to permit
fixing and supporting elements to be introduced.
A modification of the side wall portion 10 is shown in FIG. 6. Instead of
being provided with individual recesses or depressions 18 as shown in FIG.
2, which are for example of circular configuration, this form of the side
wall portion has grooves 58 which are of a dovetail-shaped configuration
and which extend from the top edge of the wall portion but which terminate
short of the lower edge thereof. Connecting members or tie members 11 with
a base portion of corresponding configuration can be fitted into the
grooves 58 and additionally secured therein by adhesive means, in certain
positions which are identified by suitable markings (not visible in FIG.
6). The remaining free portions of each groove 58, being therefore not
occupied by a respective tie member 11, provide for additionally securing
the side wall portion 10 to the concrete which is poured into and sets in
the assembly.
The embodiment shown in FIG. 7 uses a connecting member or tie element 31
which comprises two end plate portions 27 and strut members such as wires
or bars as indicated at 28 which interconnect the end plate portions 27.
The end plate portions 27 are engaged into a recess 18 in the side wall
portion 10, in a similar fashion to the embodiment shown in FIG. 2, and
are additionally secured therein by adhesive. The wires or bars 28 can be
easily welded to the end plate portions 27 which comprise sheet metal. The
mutually crossing configuration of the wires provides a certain spring
action thereby reducing the shocks or impacts produced when the shuttering
or formwork assembly is filled with concrete.
In the embodiment shown in FIG. 8, the side wall portion 10 which is shown
in perspective in provided with engagement means in the form of blind
holes 30 which are of T-shaped cr | | |
