AU623298B1

AU623298B1 - Concrete shuttering element

Info

Publication number: AU623298B1
Application number: AU69906/91A
Authority: AU
Inventors: Stephen Carde
Original assignee: Frankipile Australia Pty Ltd
Current assignee: Frankipile Australia Pty Ltd
Priority date: 1991-01-22
Filing date: 1991-01-22
Publication date: 1992-05-07
Anticipated expiration: 2011-01-22
Also published as: AU6990691A; MY107904A; EP0496719A1

Description

I COMMONWEALTH OF AUSTRALIA Patent Act 1952 J298 COMPLETE SPECTFICATTON

(ORIGINAL)

Class Int. Class Application Number Lodged Complete Specification Lodged ,,Accepted t t Published it Priority: t Art Related Art Name of Applicant Address of Applicant Actual Inventor Address for Service FRANKIPILE AUSTRALIA PTY LTD 69 Phillip Street, Parramatta, New South Wales, 2124, Australia I: I I 4t 1i 4 S Stephen Carde F.B. RICE CO., Patent Attorneys, 28A Montague Street, BALMAIN. 2041.

Complete Specification for the invention entitled: "CONCRETE SHUTTERING ELEMENT" The following statement is a full description of this invention including the best method of performing it known to us:i it 2 2

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The present invention relates to shuttering elements and a method of detaching such shuttering elements from a cast or moulded wall.

When a wall or panel is cast or moulded, the formwork or mould is usually removed from the cast section, and used for casting further sections or panels. In some cases, the formwork may simply be destroyed and new formwork used to cast further wall sections or panels. In other instances, the formwork is designed to be removed from the cast wall section or panel and reused.

When panels or walls are moulded or cast in the ground such as in the production of diaphragm walls, part of the formwork comprises a trench or excavation in the ground having the desired depth and width. The ends of the wall section or panel are set either by the ends of the trench or by suitable formwork, usually an elongated panel, known in the art as a shuttering element or stop-end, placed vertically in the trench, the width of the element being substantially equal to the width of the trench.

A hardenable material is then poured into the trench on one side of the shuttering element. The hardenable material is prevented from flowing along the entire trench by the shuttering element. In this way a panel or wall section of the desired length is cast or moulded in the ground. When the wall is substantially or completely hardened, the shuttering element is detached from the panel and moved along the trench. The process is then repeated to form further panels until the entire length of the diaphragm wall is completed.

There have previously been proposed several different types ot shuttering elements and methods of removing these shuttering elements from a cast panel or wall section.

One such method involves vertically sliding the shuttering element upwardly out of the trench.

1, t ria 3 Such vertical detachment of a shuttering element from a cast panel is difficult since there must not only be sufficient clearance above the trench to accommodate the upward motion of the shuttering element, but the detachment must take place prior to complete hardening of the cast panel due to the strong bonding forces between the panel and the shuttering element which must be overcome to slide the shuttering element away from the cast panel. Additionally, if the shuttering element is slidably detached prior to substantial hardening of the cast panel, the cast panel may simply collapse into the trench. oaO 4 *4 t q* 0O

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a Due to the difficulties with slidably detaching the shuttering element from the cast panel, it has previously .15 been proposed to pull the shuttering element away from the o cast panel. This lateral detachment method does not require large clearances above the trench and the force too a. required to pull the shuttering element away from the cast panel is substantially less than the shear forces required by the previous sliding technique. Therefore such a method allows substantially complete hardening of the cast panel prior to detachment of the shuttering element from the panel.

To assist in pulling the shuttering element away from the cast panel, there have previously been proposed several types of shuttering elements and methods of detaching the shuttering elements.

One such shuttering element comprises a series of inflatable ribs positioned between the shuttering element and the wall section. After hardening of the cast panel, the inflatable ribs are pressurised to assist in pulling the shuttering element away from the cast panel. Such a shuttering element, however, is overly complex and liable to damage when being removed from one cast panel and placed in position to form another panel.

h -4 Another prior method of detaching a shuttering element from a cast panel involves a shuttering element which extends a certain distance above the upper level of the trench. A weighted implement is then placed on the shuttering element and dropped downwardly to smash the hardenable material directly adjacent the shuttering element thereby breaking the join between the shuttering element and the cast panel. Such a weighted implement may optionally include a wedge shape such that as it progresses downwardly along the shuttering element breaking the hardenable material it simultaneously forces the shuttering element away from the wall section.

o0 Such a method is however time consuming and dangerous "°o0 due to the repeated raising and dropping of the implement :15 to break the hardenable material between the shuttering element and the cast panel. Additionally, such a method is liable to to damage that side of the shuttering element facing the cast panel, so that it may not be used for subsequent panels.

Clearly there is a need for a shuttering element and a method of removing that shuttering element from a cast panel which is simple and effective and does not cause excessive damage to the shuttering element.

t In order to ameliorate the disadvantages of the prior art it is proposed to provide a concrete shuttering element which offers a choice over the prior art and which, at least in the preferred embodiments, is both easier, simpler and more reliable to detach from a wall S" section.

In oe-- shuttering element for forming a cast panel bl element comprising an elongated partition r, and an elongate web connected to onesi aid// ad partition member in spaced apar ntiiI tially parallel relationship such tha id nQa Mau b ri n r I In one aspect, the present invention comprises a shuttering element for forming a cast panel, said element i comprising an elongated partition member, an elongate web Sconnected to one side of said partition member in spaced apart parallel relationship and a protrusion being connected to the other side of said partition member to shape an end face of said cast panel to prevent relative j lateral movement between adjacent cast panels, wherein said elongate web is adapted to be gripped by a detachment 0 means to detach said element from said cast panel.

In a preferred embodiment, said elongate web extends along the length of said elongated partition member.

In another embodiment, said protrusion means i comprises a C-shaped channel member joined along its longitudinal edges to said elongated partition member.

Ii, In another embodiment, said shuttering element includes a water stop positioning means adapted to receive ,a water stop such that upon detachment of said element it from said cast panel, said water stop is at least I 20 partially embedded in said cast panel.

ii,, In another embodiment, said elongate web is narrower than said elongated partition member.

In a second aspect, the present invention comprises a :Fr method for detachment of a shuttering element from a cast I 25 panel, said shuttering element comprising an elongated partition member, an elongate web connected to one side of said partition member in spaced apart parallel .relationship and a protrusion being connected to the other b- side of said partition member to shape an end face of said cast panel to prevent a relative lateral movement between adjacent cast panels, said method comprising engaging said elongate web with a detachment means and pulling said element away from said cast panel such that said detachment means does not contact said cast panel.

In a first embodiment, said detachment means i

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5a comprises two inwardly facing grooves adapted to receive and slide on longitudinal edges of said elongate web.

In another embodiment said detachment means is attached to an excavating grab.

Since the shuttering element of the present invention is removed by pulling the elongate web which is attached to the elongate partition member, the partition member is not likely to be damaged by the removal means and the t

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1.c c i a 1 i I II__ 1IClli* i i-_.-ill~L~i r 6 shuttering element may therefore be reused without any need to repair the partition member.

Additionally, the elongate web reinforces the partition member against bending or bowing which may be due to the pressure exerted on the element by the hardenable material in the trench or occur during detachment of the element from the cast panel.

The elongate web also guides the excavating grab for subsequent trenches thereby ensuring geometric continuity of the diaphragm wall.

In order that the nature of the present invention may Sbe more clearly understood, preferred embodiments of the invention will now be described, with reference to the accompanying drawings in which: 90*0 15 Figure 1 is a cross-sectional view of the concrete :00: shuttering element according to a first embodiment, Figure 2 is a side view of the shuttering element of Figure 1 being removed from a wall section, Figure 3 is a cross-sectional view along line A-A of Figure 2, and Figure 4 is a cross-sectional view of a shuttering element according to a second embodiment of the present invention.

Figure 1 displays the cross-section of a shuttering element 10 according to a first embodiment of the present invention. The shuttering element 10 comprises elongate partition member 11, and elongate web 13 connected to one i a side of said partition in spaced apart substantially parallel relationship. In this case, elongate web 13 is connected to and spaced from partition 11 by means of spacers 14 and 15. A protrusion 12 may optionally be connected to the other side of the elongated partition member.

As shown in Figures 2 and 3, in use an excavating bucket or grab 30 excavates a trench 31. The stability of L I 7 the excavated trench may be ensured by filling the trench with a bentonite slurry thereby preventing collapse of the trench.

The shuttering element 10 is placed vertically in the trench as shown. The elongated partition member 11 extends substantially across the entire width of the excavated trench. The material to form the cast panel is then poured into the excavation on that side of the partition 11 with protrusion 12 while the optional bentonite slurry is removed. The protrusion 12 shapes the end face of the cast panel 20. In this embodiment the protrusion 12 is a C-shaped channel member which produces an indentation in the end face of the cast panel to reduce lateral movement between adjacent cast panels.

15 In most instances, the cast panel will be formed by a hardenable material such as concrete or cement. If, however, the cast panel does not perform a support function it may be filled with any material such as COULIS, a bentonite/cement mixture which does not fully 20 harden and which produces a wall impervious to water.

Such a wall is particularly suitable for stabilising the water table during excavation.

When cast panel 20 has substantially hardened, the shuttering element 10 may be removed from the end panel and placed further along the excavation. The area of the excavation between the shuttering element 10 and the end of the cast panel is then once again filled with material to form a further panel. This "consecutive" method is repeated until the desired length of wall is completed.

Another method of forming such a length of wall is to excavate a series of spaced apart trenches and fill these trenches with material to form the cast panel. When these first cast panels have substantially hardened, the area between these cast panels is then excavated and filled with material to form the completed wall section. The I i.

mm 8 advantage of such an "alternate" process is that the operator does not have to wait for each cast panel to be substantially hardened prior to forming another cast panel as a series of spaced apart cast panels are all formed at the same time.

To remove the shuttering element 10 from the cast i panel 20, elongate web 13 is gripped by a detachment means and pulled away from the end of the cast panel 20. In this way, the detachment means at no time contacts the cast panel. Additionally, since the detachment means does not grip elongate partition 11, the partition retains its S shape when detached from the cast panel, thereby avoiding Sany possible leakage of the cast panel material past elongate partition 11 during subsequent production of further panels.

A further advantage of the present invention arises due to reinforcing that elongate web 13 gives to the whole ijshuttering element 10. The elongate web 13 may extend along the entire length of elongated partition 11 thereby reducing the possibility of elongated partition 11 bending or bowing due to the forces exerted on it by the material forming the cast panel or by continued removal of the element 10 from the cast panel.

In the embodiments shown in Figures 2 and 3, the shuttering element 10 is removed by a detachment means 32 which comprises a pair of inwardly facing grooves 21 and 22 adapted to surround and slide on the longitudinal edges of elongated web 13. In the embodiments shown, the detachment means 32 is attached to the grab In order to remove the shuttering element 10 from the cast panel, grab 30 is firstly positioned above the concrete shuttering element 10. The grab 30 is then lowered such that the longitudinal edges of elongate web 13 are received by inwardly facing grooves 21 and 22.

The grab 30 is then simply pulled away from the cast ~11-~1~~I 9 0 ~ol 0e, 0Ib~ 0 0e 0 00.( panel by cable 34 thereby pulling the shuttering element away from the cast panel. It should be noted that neither the detachment means 32 nor grab 30 contact the cast panel 20 at any time during the detachment of the shuttering element 10 from the cast panel A further advantage of the present invention arises when the detachment means is attached to grab 30. As will be clear to persons skilled in the art, despite elongated partition 11 being sized to the approximate width of trench 31, some leaking of material around the edges of the elongated partition 11 will occur. As the grab 30 is slidably lowered along the shuttering element 10, inwardly facing grooves 21 and 22 scrape off any excess material which have leaked past elongated partition 11. Further, the jaws 33 of the grab 30 may be opened while the grab is slidably lowered down the shuttering element 10. thereby

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scraping off any material allowing easier passage of the detachment means 32 along elongate web 13.

Another advantage which arises from the present invention is the use of elongate partition 13 to guide grab 30 when forming an excavation for the next cast panel of the wall section. As will be clear to persons skilled in the art, if elongate partition 13 is symmetrical about the central axis of the trench, when the grab 30 is slidably connected to the elongate partition 13 by means of detachment means 32, any excavation by grab 30 will be S in line with previously formed cast panel 20 thereby ensuring geometric continuity of the wall section.

0C While the embodiment shown in Figures 2 and 3 display detachment means 32 being attached to grab 30, it is envisaged that any means which positioned detachment means 32 on elongate web 13 and is able to pull detachment means 32 away from the end of cast panel 20, may be used to detach shuttering element 10 from wall section It is also to be noted that it is preferable for Op I I p i0 elongate web 13 to be narrower than elongate partition 11 thereby allowing detachment means 32 to slide on shuttering element 10 without detachment means 32 contacting the sides of the trench 31.

Figure 4 is a cross-sectional view of a shuttering element in accordance with the second embodiment of the present invention. The shuttering element 10 once again comprises elongated partition 11, protrusion 12 and elongate web 13 connected to the elongated partition 11 in a spaced apart substantially parallel relationship by spacers 14 and This second embodiment, however, includes a water stop positioning device 16 on protrusion 12. The water stop positioning device 16 is provided with a groove 17 15 which, in this case, tapers slightly inwardly. In use, a ~water stop, which comprises a strip of resilient material, is placed in groove means 17 prior to the shuttering element 10 being placed in the excavated trench. As the panel material is poured into the trench it will surround the water stop and when this material sets and the shuttering element 10 is removed from the cast panel the water stop, which is embedded in the cast panel 20, is pulled out from groove 17. In this way a water stop may be positioned at the end of ea.ch cast panel simultaneously with the removal of the shuttering element from the wall section From the foregoing it should be apparent that the invention encompasses an advantageous advance in the prior art or at least a commercial alternative to the prior art. Further, it should be clear that the invention may be embodied in other specific forms without departing from the spirit or scope or the essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

2. A shuttering element as claimed in claim 1 wherein oo said elongate web extends along the entire length of said elongate partition member.
3. A shuttering element as claimed in claim 1 or 2 Po. wherein said protrusion comprises a C-shaped channel :Jot* member joined along its longitudinal edges to said S54o elongated partition member.
4. A shuttering element as claimed in any one of the preceding claims wherein said shuttering element includes a water stop positioning means adapted to receive a water t stop, such that upon detachment of said element from said cast panel, said water stop is at least partially embedded (i in said cast panel. 25 5. A shuttering element as claimed in any one of the preceding claims wherein said elongate web is narrower than said elongated partition member. A method for detachment of a shuttering element from a cast panel, said shuttering element comprising an elongated partition member, an elongate web connected to one side of said partition member in spaced apart parallel relationship and a protrusion being connected to the other side of said partition member to shape an end face of said cast panel to prevent a relative lateral movement between adjacent cast panels, said method comprising engaging said it 12 elongate web with a detachment meanj and pulling said ,u ,element away from said cast panel such that said detachment means does not contact said cast panel.
7. A method for detachment of a shuttering element as claimed in claim 7 wherein said detachment means comprises two inwardly facing grooves adapted to receive and slide on longitudinal edges of said elongate web.
8. A method as claimed in claim 6 or claim 7 wherein said detachment means is attached to an excavating grab. j 10 9. A shuttering element substantially as hereinbefore described with reference to the accompanying drawings.
10. A method for detachment of a shuttering element from a cast panel substantially as hereinbefore described with reference to the accompanying drawings. DATED this 31st day of January 1992 e0 o0, FRANKIPILE AUSTRALIA iPTY. LTD. Patent Attorneys for the t, Applicant: S' F.B. RICE CO. 44*