EP0454098A2 - Process for making the bottom piece of a shaft and apparatus for carrying out the process - Google Patents

Abstract

A process for making concrete elements (10) of a substantially pot-shaped form is proposed, in which the concrete elements (10) are formed in the fabrication position, which is the inverse of the service position, in a mould (12), which has a mould core (14) and a radially outer mould mantle (16), arranged at a distance from the mould core (14). During the course of the process, an insert element (34) is placed on the upper end (14b) of the mould core (14), a mould cavity (24), formed between mould core (14) and mould mantle (16), is filled with concrete until the insert element (34) is completely covered to a desired layer thickness, the filled-in concrete is compacted, the concrete element (10) is stripped and allowed to set, the concrete element (10) remaining in the fabrication position at least until after setting and the projection of the outer circumference (34a) of the insert element (34) running on a plane running perpendicularly to the axis of the concrete element (10) between the projection of the outer circumference (14c) of the mould core (14) and the projection of the inner circumference (16a) of the mould mantle (16). <IMAGE>

Description

• a) Auflegen eines Einleg-Elements auf das obere Ende des Formkerns,
• b) Befüllen eines zwischen Formkern und Formmantel ausgebildeten Formhohlraums mit Beton bis zur vollständigen Bedeckung des Einleg-Elements in einer gewünschten Schichtdicke,
• c) Verdichten des eingefüllten Betons,
• d) Entschalen des Betonformteils und
• e) Aushärten des Betonformteils,

wobei das Betonformteil zumindest bis nach dem Aushärten in der Fertigungslage verbleibt.The invention relates to a method for producing molded concrete parts in an essentially pot-shaped form with a base adjoining side walls, in particular shaft lower parts or shaft base pieces.
wherein the concrete molded parts are formed in a shape opposite to the position of use in the production position, which has a mold core and a radially outer mold jacket arranged at a distance from the mold core, the method comprising the steps:

• a) placing an insert element on the upper end of the mandrel,
• b) filling a mold cavity formed between the mold core and the mold jacket with concrete until the insert element is completely covered in a desired layer thickness,
• c) compacting the filled concrete,
• d) demoulding the concrete part and
• e) hardening of the molded concrete part,

wherein the molded concrete part remains in the production position at least until after curing.

In the conventional production of molded concrete parts in a substantially pot-shaped form, in particular of manhole bases or manhole bottoms, as a result of the removal of the formwork prior to curing, the problem arose that the base of the molded concrete part deformed under its own weight during the period from the formwork removal to complete hardening . For this purpose, reference is also made to the description of FIGS. 8 and 9.

To solve this problem, a generic method has been considered, in which the bottom of the concrete molding is supported by an inner, recoverable formwork panel until it has completely hardened which, in turn, is carried through an opening formed in the bottom by a holding plate placed after the filling and supported over the side wall. After curing, the two plates must be removed by hand from the bottom of the molded concrete part. In addition, the opening in the bottom of the concrete molding must be poured with concrete. In addition, reference is made to the description of FIGS. 10-14.

This generic method has various disadvantages: On the one hand, productivity is reduced by the large number of necessary work steps, in particular by the manual attachment and removal of the support plates. On the other hand, the concrete subsequently poured into the floor opening does not form a perfect, in particular no watertight, bond with the molded concrete part.

In contrast, it is an object of the invention to provide a method of the type mentioned, which enables the production of molded concrete parts with a perforation-free and non-deformed bottom with high productivity.

This object is achieved by using a lost insert element, the outer circumference of which projects beyond the outer circumference of the mold core at least on part of the circumference and, with the inner circumference of the mold shell, offers a filling cross section which is sufficient for filling the mold cavity.

After the mold has been filled with concrete and the filled-in concrete has been compacted, the outer circumference of the insert element, which projects radially beyond the outer circumference of the mold core, is embedded in the concrete. The insert element supports the bottom of the concrete molding and distributes its weight over the one embedded in the concrete Outer circumference on the side wall of the concrete molding. In this way, deformations of the bottom of the concrete molding can be reliably prevented without an opening in the bottom having to be provided to support the weight of the bottom. After hardening, the insert element remains as lost formwork in the concrete molding.

In one embodiment, the insert element can be designed as an insert plate or insert shell.

In order to be able to further stabilize the insert plate for carrying the weight bearing on it, it is proposed in a further development of the invention that the insert element is provided with stiffening ribs on its side facing away from the mandrel.

As an alternative, however, it can also be provided that reinforcement elements, in particular made of structural steel, are placed on the side of the insert plate facing away from the mandrel.

Because the insert element is convex, the insert element with its concave side being placed on the upper end of the mandrel, the insert element can be given a high degree of stability in a particularly simple manner.

As an alternative to this, it can also be provided that the insert element is conical, the insert element being placed with its concave side on the upper end of the mandrel.

Because the insert element is designed with a channel, the concrete molding can also be used to guide water. Here, the channel does not have to be straight, but can also be curved within the molded concrete part.

In order to be able to connect line pipes to the molded concrete part, it is proposed that the insert element for the formation of inlets and / or outlets have essentially tubular approaches.

In order to be able to reliably ensure that the mold cavity is filled properly, it is proposed that the filling cross section be at least 30%, preferably between 40% and 90%, of the cross section of the mold cavity.

In a development of the invention it is proposed that the outer circumference of the insert element runs at a substantially constant distance from the outer circumference of the mandrel. It can be provided that the distance of the outer circumference of the insert element from the inner circumference of the shaped jacket is at least 20% of the distance at the respective point between the outer circumference of the mandrel and the inner circumference of the shaped jacket, preferably between 30% and 90%, for complete filling of the mold cavity with concrete.

Alternatively, it is proposed that the outer circumference of the insert element has projections projecting radially outwards. It is further preferred that the projections are distributed over the circumference of the insert element and have an angular spacing of 15 ^o to 120 ^o , preferably about 60 ^o , and that each projection has an average angular extent of 5 ^o to 15 ^o , preferably about 10 ^o , owns. In this way, an effective distribution of the weight of the bottom of the concrete molding to the side wall can be ensured, while at the same time it can be ensured that the concrete fills the mold completely, ie in particular without cavities under the outer peripheral edge of the insert element.

Fig. 1

eine geschnittene Seitenansicht zur Erläuterung des erfindungsgemäßen Verfahrens zur Herstellung von Betonformteilen;

Fig. 2

eine geschnittene Seitenansicht einer ersten Ausführungsform eines nach dem erfindungsgemäßen Verfahren hergestellten Betonformteils im entschalten Zustand;

Fig. 3 - 6

Ansichten analog Fig. 2 weiterer Ausführungsbeispiele von nach dem erfindungsgemäßen Verfahren hergestellten Betonformteilen;

Fig. 7

eine schematische Darstellung zur Erläuterung des Verlaufs des Außenumfangs des Einleg-Elements;

Fig. 8 und 9

Ansichten analog den Fig. 1 und 2 zur Erläuterung eines bekannten Verfahrens; und

Fig. 10 - 14

Ansichten zur Erläuterung eines in Betracht gezogenen, gattungsgemäßen Verfahrens; hierbei ist:

Fig. 10

eine Ansicht analog den Fig. 1 und 8;

Fig. 11

eine geschnittene Seitenansicht eines nach diesem Verfahren hergestellten Betonformteils;

Fig. 12

eine Ansicht analog den Fig. 2 und 9;

Fig. 13

eine Ansicht des nach diesem Verfahren hergestellten Betonformteils nach Abnahme der Platten; und

Fig. 14

das nach diesem Verfahren hergestellte Betonformteil in seiner Gebrauchslage mit ausgegossener Bodendurchbrechung.

The invention is explained below with reference to the drawing. They represent:

Fig. 1

a sectional side view to explain the method according to the invention for the production of molded concrete parts;

Fig. 2

a sectional side view of a first embodiment of a molded concrete part produced by the method according to the invention in the detached state;

3 - 6

Views analogous to FIG. 2 of further exemplary embodiments of molded concrete parts produced by the method according to the invention;

Fig. 7

a schematic representation to explain the course of the outer circumference of the insert element;

8 and 9

Views analogous to Figures 1 and 2 to explain a known method. and

Figures 10-14

Views for explaining a generic method under consideration; here is:

Fig. 10

a view analogous to Figures 1 and 8;

Fig. 11

a sectional side view of a molded concrete part produced by this method;

Fig. 12

a view analogous to Figures 2 and 9.

Fig. 13

a view of the molded concrete part produced by this method after removal of the plates; and

Fig. 14

the molded concrete part produced according to this process in its position of use with poured-out opening in the bottom.

In a known, non-generic method for the production of essentially pot-shaped molded concrete parts, namely shaft base pieces 10 ', a mold 12 is used according to FIG. 8, which consists of a mold core 14, a mold jacket 16, a lower sleeve 18 and a mold upper part 20. The upper mold part 20 can be transferred from a lowered position (see FIG. 8) to a raised position and vice versa by means of a lifting device (not shown in FIG. 8). For this purpose, the upper mold part 20 can be moved in a direction running essentially parallel to the axis of the mold core 14 and indicated by the double arrow A in FIG. 8. The lower sleeve 18 can be moved between a lower position (see FIG. 8) and an upper position (see FIG. 8) by a lifting device 22 in a direction that is also essentially parallel to the axis of the mandrel 14 and is indicated in FIG. 8 by the double arrow B. . 9) can be adjusted.

The mold jacket 16 runs at a radial distance from the outer circumference 14a of the mold core 14. In the axial direction, the mold jacket 16 projects beyond the upper boundary surface 14b of the mold core 14. The lower sleeve 18 is arranged radially between the mold core 14 and the mold jacket 16 and stands on the surface shown in FIG. 8 upper end 22a of the lifting device 22.

In the manufacture of shaft base pieces 10 ', the known method proceeds as follows: If the lifting device 22 with the lower sleeve resting on it 18 is in the lower position (cf. FIG. 8) and the upper mold part 20 is in the raised position, a predetermined amount of concrete is placed in a mold cavity 24 defined by the mold core 14, the lower sleeve 18 and the mold jacket 16 beyond the upper boundary surface 14b the mold core 14 filled. The concrete layer above the upper boundary surface 14b of the mold core 14 is then smoothed by lowering the upper mold part 20. For compaction, the entire mold 12 can be shaken by a vibrating device, not shown, in order to achieve a uniform distribution of the filled concrete. Thereafter, the lower sleeve 18 and with it the manhole base piece 10 'are moved out of the mold 12 by the lifting device 22 and are thus released (see FIG. 9). In Figure 9, the lower sleeve 18 is approximately flush with the floor of the manufacturing hall. The shaft base piece 10 'is then brought by a transport device, for example a forklift truck, together with the lower sleeve 18 to a storage location, where it preferably remains until the concrete has completely hardened.

The above-described manufacturing method for manhole base pieces 10 'has the disadvantage that the base part 10'a deforms during the period from the formwork to the complete hardening of the concrete as a result of its own weight (see FIG. 9), since the filled concrete withstands tensile stresses is not dimensionally stable. In the worst case, the bottom part can get 10'a cracks. Since the filled-in concrete is dimensionally stable against pressure loads, the side wall 10'b of the shaft base piece 10 'is not subject to any deformation.

To avoid the disadvantage of deformed floor parts, a method was considered, which will be explained in the following with reference to FIGS. 10-14.

In this method, before the mold cavity 24 of the mold 12 is filled with concrete, an inner formwork plate 26 (see FIG. 10), which is provided with a spacer 26a and a screw bolt 26b, is placed on the upper end 14b of the mold core 14. The upper mold part 20 'has a recess 20'b formed at its lower end 20'a, in which the screw bolt 26b of the plate 26 is received when the upper mold part 20' is in its lowered position.

After compaction, the upper mold part 20 'is raised again and a holding plate 28 is placed on the manhole bottom piece 10' '. The holding plate 28 is firmly connected to the formwork plate 26 via a locking screw nut 30 screwed onto the screw bolt 26b (see FIG. 11). The diameter of the formwork plate 26 corresponds to the diameter of the mold core 14, while the holding plate 28 extends up to the inner circumference 16a of the mold jacket 16 and is supported on the side wall of the shaft bottom piece 10 ″. Then the manhole base piece 10 ″ is removed from the mold by extending the lifting device 22 (see FIG. 12) and, as described above, removed for the hardening of the concrete. In this state, the base part 10 ″ a of the manhole base piece 10 ″ is received between the plates 26 and 28 and is supported by them so that it cannot deform under its own weight.

After curing, the locking screw nut 30 is loosened and the plates 26 and 28 are removed from the manhole base piece 10 ″ (see FIG. 13). Since the spacer 26a was also removed with the plate 26, an opening 10''c remains in the bottom part 10''a of the manhole bottom piece 10 ''. This opening 10 ″ c is filled with mortar 32 after the manhole bottom piece 10 ″ has been brought into its position of use according to FIG. 14.

Although this method prevents deformation of the base part 10 ″ a of the manhole base piece 10 ″, it has some serious disadvantages: on the one hand, the plates 26 and 28 have to be attached and removed again by hand, which results in a considerable reduction in productivity. On the other hand, after the plates 26 and 28 have been removed, an opening 10 ″ c remains in the base part 10 ″ a of the manhole base piece 10 ″ and must be filled with mortar 32 in an additional work step. Since this mortar 32 does not sufficiently bond with the already hardened concrete, it cannot be guaranteed that the manhole base is watertight.

In the following, the method according to the invention is to be described in detail with reference to FIGS. 1 and 2, which is characterized by high productivity and with which the production of reliably watertight manhole base pieces is made possible.

The method according to the invention can be carried out with the same device with which the known, non-generic method described above with reference to FIGS. 8 and 9 was carried out. The method according to the invention differs from the known method of the generic type in that before the mold cavity 24 is filled with concrete, an insert element 34, for example an insert plate (see FIG. 1), on the upper end 14b of the mold core 14 is placed, which has an outer diameter D₂ (see. Fig. 2), which is larger than the outer diameter D₁ of the concrete core 14. That is, the insert plate 34 is dimensioned such that its outer circumference 34a, seen in the radial direction, between the outer circumference 14c of the upper end 14b of the mold core 14 and the inner circumference 16a of the mold jacket 16.

The insert element 34 can be made, for example, of construction timber, pressboard, plastic, metal, fiber-reinforced cement or the like. Preferably, a material that adheres to concrete is used.

When the mold cavity 24 is filled, the concrete flows between the outer periphery 34a of the insert plate 34 and the inner periphery 16a of the mold jacket 16 to the lower sleeve 18. After the filled concrete has been smoothed through the upper mold part 20, if necessary with simultaneous shaking, for uniform distribution of the filled Concrete, the manhole bottom section 10 is released by extending the lifting device 22 (see FIG. 2). The shaft base piece 10 is then transported to a storage location together with the lower sleeve 18 using a transport device, for example a forklift truck, and is left there until it has completely hardened.
During this period, the insert plate 34 picks up the weight of the base part 10a of the manhole bottom piece 10 and distributes this weight in the area of its outer circumference 34a to the side wall 10b of the manhole bottom piece 10. This reliably prevents deformation of the bottom part 10a without breaking through it To have to accept bottom part 10a. After hardening, the insert plate 34 remains as lost formwork in the shaft bottom piece 10.

In order to increase the stability of the base part 10a of the manhole bottom piece 10 and to provide a stiffening for the insert plate 34, additional inserts, for example in the form of structural steel rods 36, can be placed on the insert plate 34 before the mold 12 is filled with concrete. As an alternative to this, it is also possible to provide the insert plate 34 on its side facing away from the mold core 14 with stiffening ribs.

4 shows a further exemplary embodiment of a manhole base piece produced by the method according to the invention, analog parts being provided with the same reference numerals as in FIGS. 1 and 2, but increased by the number 100.

In this exemplary embodiment, the insert element 134 is of slightly convex design. Due to the shape that bulges out in the direction of the bottom part 110a of the shaft bottom piece 110 that bears on it, the insert element 134 has better statics. Thus, insert elements 134 made of lighter and less stable materials can also be used to produce manhole covers according to the method according to the invention.

A further exemplary embodiment of a manhole base piece produced by the method according to the invention is shown in FIG. 5, analog parts being provided with the same reference numerals as in FIGS. 1 and 2, but increased by the number 200.

In this exemplary embodiment, the insert element 234 has a conical shape, the tip of the cone being directed towards the bottom part 210a of the shaft base piece 210 which bears on the insert element 234. The conical shape also has good static properties, so that the use of such an insert element 234 has the same advantages as the use of a convex insert element 134 described above.

FIG. 6 shows a further exemplary embodiment of a manhole base piece produced by the method according to the invention, analog parts being provided with the same reference numerals as in FIGS. 1 and 2, but increased by the number 300.

In this exemplary embodiment, the insert element 334 not only takes over the supporting function for the base part 310a of the shaft bottom piece 310, but also simultaneously takes over the function of the water flow. For this purpose, the insert element 334 is formed with a channel 334a. In order to enable the connection of piping systems, not shown in FIG. 6, to the shaft bottom piece 310, the insert element 334 is provided on its channel 334a with an essentially tubular extension 334b. When the lifting device 322 is retracted, this projection 334b lies in a form-fitting manner between the mold core 314 and the molding jacket 316, so that when the mold is filled with concrete, it cannot penetrate into the space 334b1 enclosed by the tubular projection 334b. A manhole bottom piece 310 can have a plurality of such inflow or outflow approaches 334b. The channel 334a does not have to run in a straight line in the shaft bottom piece 310, but can also take a curved course.

When dimensioning the outer circumference of the insert element between the outer circumference of the mandrel and the inner circumference of the molded jacket, it is desirable on the one hand to make the outer circumference of the insert element as large as possible in order to ensure good distribution and support of the load on the insert element To reach the weight of the bottom part of the manhole base. On the other hand, it is desirable to make the outer circumference of the insert element as small as possible in order to be able to ensure that the concrete actually completely flows under the insert element when the mold is filled.

It has been found that these two mutually opposing requirements can be met in a particularly favorable manner at the same time by forming the insert element according to FIG. 7 with projections 38 projecting radially outward from its outer circumference 34a. With these projections 38 that extend almost to the inner circumference 16a of the mold jacket 16, the insert element 34 can effectively distribute the weight of the bottom part 10a of the manhole bottom piece 10 resting on it onto the side wall 10b of the manhole bottom piece, while concrete is being poured into the mold cavity 24 (see FIG. 1) Concrete can easily flow past the insert element through the spaces 40 provided between the projections 38 (see FIG. 7) and can completely fill the mold cavity 24.

Claims (13)

Method for producing molded concrete parts (10) in an essentially pot-shaped form with a base (10a) adjoining side walls (10b), in particular shaft lower parts or shaft bottom pieces,
wherein the concrete molded parts (10) are formed in the opposite production position to the use position in a mold (12) which has a mold core (14) and a radially outer mold jacket (16) arranged at a distance from the mold core (14), the method comprising the Steps : a) placing an insert element (34) on the upper end (14b) of the mandrel (14), b) filling a mold cavity (24) formed between the mold core (14) and the mold jacket (16) with concrete until the insert element (34) is completely covered in a desired layer thickness, c) compacting the filled concrete, d) stripping the concrete part (10) and e) hardening of the molded concrete part (10), wherein said concrete form member (10) remains at least until after the curing in the production position, characterized
by using a lost insert element (34), the outer circumference (34a) of which extends beyond the outer circumference (14c) of the mold core (14) at least on a part of the circumference and one for the filling of the mold shell (16) with the inner circumference (16a) Mold cavity (24) forms sufficient filling cross section, Method according to claim 1,
characterized,
that the insert element is designed as an insert plate (34) or insert shell. Method according to one of claims 1 or 2,
characterized,
that the insert element (34) is provided on its side facing away from the mandrel (14) with stiffening ribs. Method according to one of claims 1-3,
characterized,
that reinforcement elements (36), in particular made of structural steel, are placed on the side of the insert element (34) facing away from the mandrel (14). Method according to one of claims 1-4,
characterized,
that the insert element (134) is convex, the insert element (134) being placed with its cocave side on the upper end (114b) of the mandrel (114). Method according to one of claims 1-4,
characterized,
that the insert element (234) is conical, the insert element (234) being placed with its cocave side on the upper end (214b) of the mandrel (214). Method according to one of claims 1-6,
characterized,
that the insert element (334) is formed with a channel (334a). Method according to one of claims 1-7,
characterized,
that the insert element (334) has substantially tubular projections (334b) for forming inlets and / or outlets. Method according to one of claims 1-8,
characterized,
that the filling cross section is at least 30%, preferably between 40% and 90% of the cross section of the mold cavity (24). Method according to one of claims 1-9,
characterized,
that the outer circumference (34a) of the insert element (34) extends at a substantially constant distance from the outer circumference (14c) of the mandrel (14). A method according to claim 10,
characterized,
that the distance of the outer circumference (34a) of the insert element (34) from the inner circumference (16a) of the molded casing (16) is at least 20% of the distance at the respective point between the outer circumference (14c) of the molded core (14) and the inner circumference (16a) of the shaped jacket (16) is preferably between 30% and 90%. Method according to one of claims 1-9,
characterized,
that the outer outer circumference (34a) of the insert element (34) has radially outwardly projecting projections (38). Method according to claim 12,
characterized,
that the projections (38) are evenly distributed over the circumference of the insert element (34) and have an angular distance of 15 ° to 120 °, preferably about 60 ° and
that each projection has an average angular extent of 5 ^o - 15 ^o , preferably about 10 ^o .

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