EP1911908A1

EP1911908A1 - Method for erecting a concrete wall

Info

Publication number: EP1911908A1
Application number: EP06122162A
Authority: EP
Inventors: Leo Gielbert
Original assignee: Strukton Betonbouw BV
Current assignee: Strukton Betonbouw BV
Priority date: 2006-10-12
Filing date: 2006-10-12
Publication date: 2008-04-16

Abstract

A method for erecting a concrete wall on a ground surface using a vertically movable shuttering is provided, wherein before pouring concrete a lining is provided on the parts of the shuttering intended to contact the concrete, which lining during the movement of the vertically movable shuttering is maintained stationary relative to the concrete, and which lining will be removed from the concrete wall when the concrete has cured to a certain degree. The lining is maintained stationary by being temporarily mechanically connected to a stationary part, for example the ground surface, the concrete wall itself or a separate support frame.

Description

The invention relates to a method for erecting a concrete wall on a ground surface using a vertically movable shuttering, wherein before pouring concrete a lining is provided on the parts of the shuttering intended to contact the concrete, which lining during the movement of the vertically movable shuttering is maintained stationary relative to the concrete, and which lining will be removed from the concrete wall when the concrete has cured to a certain degree.
As is known generally, during such a method the vertically movable shuttering 'surrounds' the wall to be erected and is slowly lifted while simultaneously concrete is poured into the top of the shuttering. At the bottom the already fabricated part of the wall leaves the shuttering.
Without the use of a lining the speed with which the shuttering can be lifted would be strongly limited to avoid an excessive moisture loss from the poured concrete with concurrent detrimental effect on the final quality of the concrete. Although, therefore, the concrete curing speed would allow an increase of the lifting speed (in other words, the concrete already would have cured sufficiently to leave the lower side of the shuttering without sagging), the moisture loss after leaving the shuttering would be too high then. Further, because of the friction occurring between the poured concrete and the moving shuttering, the power demand for lifting the shuttering would strongly increase with an increase of the lifting velocity. Finally, an increase of the lifting velocity would negatively influence the surface quality, and thus appearance, of the finished concrete wall.
According to the state of the art, see FR-A-2 177 180 , a lining is supplied at the top of the shuttering corresponding to the lifting of the shuttering. After being supplied the lining does not move relative to the poured concrete, but assumes a fixed position relative thereto. When the shuttering is lifted, an already fabricated part of the concrete wall leaves the shuttering while still covered by the lining. This offers several advantages: firstly the lining prevents an excessive moisture loss of the poured concrete; secondly the lining offers a low friction between itself and the moving shuttering; thirdly the surface quality of the concrete wall can be improved notwithstanding the fact that the shuttering is moved relative to the concrete wall. These advantages allow an increase of the lifting velocity of the vertical movable shuttering (as an example, using a method without lining velocities up to 3,5 m/24h are achieved, whereas according to the method using a lining velocities up to 1 - 1,5 m/h seem realistic). When the concrete has cured sufficiently, the lining will be removed from the concrete wall.
According to this state of the art the lining is provided by caterpillar-like elements which are supported at their side facing away from the concrete wall by a support member which corresponds to a movable shuttering, and which caterpillar-like elements should move around in such a manner that the parts thereof in contact with the poured concrete do not move relative thereto.
It is an object of the present invention to provide an improved method for producing a concrete wall using a vertical movable shuttering.
Thus, in accordance with the present invention the method is characterized in that the lining comprises at least one separate lining element which is maintained stationary by being temporarily mechanically connected to a stationary part.
As a result no complex measures are required, nor for applying and removing the lining, nor for maintaining the lining stationary relative to the poured concrete, as is required for obtaining an acceptable surface quality of the completed concrete wall.
In a preferred embodiment of the method according to the invention, said stationary part is the ground surface on which the concrete wall is erected. However, as nonlimiting examples, it is also possible that said stationary part is a part of the concrete wall that already has cured to a certain degree, or that said stationary part is a separate support frame positioned alongside the concrete wall being erected.
According to yet another preferred embodiment of the method according to the present invention, the lining further is supported temporarily in a direction substantially perpendicularly to its surface.
Such a support avoids that part of the lining moves away from the concrete wall when the movable shuttering is lifted above such part of the lining. Such a movement, for example, could be a result of the weight of the lining, and results in a space between the lining and the concrete wall negatively influencing the surface quality of latter.
For example, such a support may be provided by support members connected to a separate support frame positioned alongside the concrete wall being erected. This support frame may be the same support frame to which the lining is mechanically connected to keep it stationary.
Of course, both functions of connecting the lining mechanically to such a support frame and supporting the lining in a direction substantially perpendicularly to its surface could be combined in one and the same member (or a number of such members).
According to an alternative embodiment of the method, the support is provided by reinforcement members attached to and extending along the lining. Such reinforcement members may be profiled members or alike which can be attached quickly and easily to the lining part when the movable shuttering has been lifted sufficiently to expose such part.
Yet another embodiment of the method according to the present invention is used for erecting a concrete wall of which one side engages an already existing structure, such as for example a sheet piling or the wall of an excavation, wherein opposite said structure, at a certain distance thereto, a support frame for the vertically movable shuttering is positioned along which the vertically movable shuttering will be lifted during pouring concrete, which support frame will be removed after completing the concrete wall.
Presently there is an increase of situations in which a concrete wall has to be erected in front of (and engaging) an already existing structure, such as a sheet piling or wall of an excavation (such as, for example, excavations for the construction of a subway). Nowadays in such situations stationary shutterings are used. However, for handling the enormous loads occurring during pouring concrete, specially designed supporting frames or anchors connecting the shuttering to the already existing structure are used which make the method time consuming and expensive.
The method according to the above mentioned embodiment, however, offers the possibility of using a much smaller vertical movable shuttering (compared to the massive stationary shuttering with supporting frame), which leads to smaller loads that have to be transferred to the surroundings. Thus it is possible to use much simpler, and thus less time consuming and less costly, supporting frames for transferring loads to the surroundings (floors, frames, sheet pilings etcetera).
When using such a method, preferably an upper part of the support frame is connected to the already existing structure. Because of the relative moderate loads occurring during pouring the concrete wall, such a connection at an upper part of the support frame will be sufficient to handle the loads. The dimensions of the constitutive parts of the support frame itself also will be limited and standardised constitutive parts (profiles, beams) may be used without the need for reinforcing measures.
However it is possible too that a lower part of the support frame is connected to the already existing structure or to the ground surface.
In a preferred embodiment of the at the interface between vertically moving shuttering and lining a material is positioned offering a low degree of friction. Such a material also could be positioned at the interface between vertically moving shuttering and support frame.
Evidently such a low degree of friction has a positive influence on the advantages mentioned above.
The lining may be provided in different manners. Preferably the lining comprises a number of separate elements adjoining each other. The handling of such separate elements is easy compared to the provision of a single unitary. This handling not only relates to the provision of the lining before the concrete is poured, but also relates to the removal of the lining from the concrete wall when the concrete has cured sufficiently.
When, in accordance with the above, the lining indeed comprises a number of separate elements, each element could comprise a multi-ply panel coated with phenol resin. However, such multi-ply also could be provided when the lining comprises a single unitary part or only a very reduced number of lining parts. Such a multi-ply coated with phenol resin is an example of a lining which, on one hand, offers all the required characteristics (among which moisture barrier, low friction) and, at the other hand, is durable and can be removed from the completed wall in an easy manner without damaging the surface of the concrete wall, thus providing the wall with a good quality surface.
It will be clear that for obtaining good results, also other materials and other coatings could be used for the lining.
As an alternative to the use of multiple separate lining elements, according to another embodiment the lining comprises a flexible sheet. Generally such a flexible sheet would comprise a single unitary part, but it is also conceivable that the lining is made up of a number of separate flexible sheets (which, then, preferably should be positioned in an overlapping manner such as to provide a continuous lining).
Of course, when using such a flexible sheet as a lining, it should be strong enough to withstand damage during handling at a building site at which, often, conditions are harsh.
The invention is not limited to the embodiments described before which may be varied widely within the scope of the invention as defined by the appending claims.

Claims

Method for erecting a concrete wall on a ground surface using a vertically movable shuttering, wherein before pouring concrete a lining is provided on the parts of the shuttering intended to contact the concrete, which lining during the movement of the vertically movable shuttering is maintained stationary relative to the concrete, and which lining will be removed from the concrete wall when the concrete has cured to a certain degree, characterized in that the lining comprises at least one separate lining element which is maintained stationary by being temporarily mechanically connected to a stationary part.
Method according to claim 1, wherein said stationary part is the ground surface on which the concrete wall is erected.
Method according to claim 1, wherein said stationary part is a part of the concrete wall that already has cured to a certain degree.
Method according to claim 1, wherein said stationary part is a separate support frame positioned alongside the concrete wall being erected.
Method according to any of the previous claims, wherein the lining further is supported temporarily in a direction substantially perpendicularly to its surface.
Method according to claim 5, wherein the support is provided by support members connected to a separate support frame positioned alongside the concrete wall being erected.
Method according to claim 5, wherein the support is provided by reinforcement members attached to and extending along the lining.
Method according to any of the previous claims and used for erecting a concrete wall of which one side engages an already existing structure, such as for example a sheet piling or the wall of an excavation, wherein opposite said structure, at a certain distance thereto, a support frame for the vertically movable shuttering is positioned along which the vertically movable shuttering will be lifted during pouring concrete, which support frame will be removed after completing the concrete wall.
Method according to claim 8, wherein an upper part of the support frame is connected to the already existing structure.
Method according to claim 8 or 9, wherein a lower part of the support frame is connected to the already existing structure or to the ground surface.
Method according to any of the previous claims, wherein at the interface between vertically moving shuttering and lining a material is positioned offering a low degree of friction.
Method according to any of the previous claims and claim 8, wherein at the interface between vertically moving shuttering and support frame a material is positioned offering a low degree of friction.
Method according to any of the previous claims, wherein the lining comprises a number of separate elements adjoining each other.
Method according to any of the previous claims, wherein the lining comprises multi-ply coated with phenol resin.
Method according to any of the previous claims, wherein the lining comprises a flexible sheet.
Method according to claim 15, wherein the flexible sheet is a reinforced plastic sheet.