EP2189586B1 - Panel element with reinforcement - Google Patents

Abstract

The plate element (10) has laterally adjacent fields (51) of a grid-shaped structure (50), where the fields form an elongated support strip (60). Individual support areas (30) are connected with each other, and are reinforced. The support strip has a solid area (70), where the laterally adjacent fields form an elongated carrier strip (80) with hollow body areas (20). An independent claim is included for a method for manufacturing a plate element, particularly concrete plate element.

Description

The invention relates to a prestressed plate element according to the preamble of claim 1 and a preferred use of such a plate element according to claim 13 and a production method for a plate element according to claim 14.

It is already known to produce particularly slender concrete panel elements and in particular flat-roof constructions based on hollow bodies embedded therein. The plate elements specified in this case are so-called "limp-reinforced" elements whose reinforcement consists of orthogonally arranged reinforcing bars which absorb the tensile forces arising in the concrete. The static performance of this lightweight technology allows e.g. the blue of slim and at the same time wide-stretched flat-roof constructions with simultaneous resource efficiency. Depending on the diameter and the geometry of the hollow body, ceiling thicknesses of approximately 20 cm are possible.

In the case of so-called "prestressed" panel elements, on the other hand, additional tensioning elements, such as cables, for example, are installed, which are tightened after the concrete has hardened. This makes it possible to generate additional forces that can compensate for the loads generated by the dead weight to a certain degree. Depending on the geometrical arrangement of the cables, only a compressive force is generated by the prestressing, ie the cables lie parallel to the ceiling plane, or additionally a deflecting force acting in the perpendicular to the ceiling plane, in the case of a parabolic or trapezoidal or so-called "free position" of the cables. The deflection force generated by the bias varies in practice between 80% and 100% of the inherent ceiling weight. Depending on the construction standard, it is also possible, in addition to the dead weight and the payload acting on the ceiling by the Umlenkkräfte to compensate for the tensioning cable.

Preloaded plate elements thus also contain tensioning elements in addition to the "limp" reinforcing bars. In extreme cases, the addition of "limp" reinforcement can be reduced to a constructive minimum, e.g. for the absorption of parasitic, locally occurring constraining forces and as reinforcement against surface cracks, when the dead weight and the payload of the element are completely compensated by the deflection forces.

Necessary preloading devices are tension cables, sleeves surrounding the cables, injection materials which are inserted between sleeve and cable after tightening depending on the laying process, anchor heads, couplings, support aids for the sleeves and cables, and tensioning devices.

The mass of ceiling weight to be compensated by the deflecting forces of the tensioning cables is directly proportional to the applied tensioning force and thus to the cross section of tensioning cables used.

The tension cables are made of high-strength steel, which has a particularly high tensile strength. The manufacture of the cables is therefore subject to strict qualitative specifications, with the result that the cost of the cable is many times higher than the cost of conventional "limp" reinforcing steel.

At the edges of the ceiling, the tensioning cables are caught in anchor heads, which dissipate the cable tensions into the concrete. Each tension cable requires its own anchor heads on both opposite edges of the ceiling. These anchor heads are an additional cost driver.

The use of the preload allows the bridging of larger spans while minimizing the ceiling thickness and thereby the ceiling own weight. In addition, the preload allows better control of concrete cracking due to horizontal constriction. Another advantage of prestressing is the minimized deformation of the ceiling, which is often the decisive criterion for ceiling thickness when designing concrete floors. The use of prestressing can also optimize the construction time as the formwork of a prestressed ceiling can be removed sooner.

However, a further increase in the performance of limp-reinforced or prestressed slab elements does not seem possible so far.

The publication AU 505 760 B2 discloses a plate member according to the preamble of claim 1. Its components may have a downwardly bulged area and be fabricated from concrete. These components are then arranged and fixed to each other at the construction site. For this purpose, clamping elements are used, which run along the side edges of the respective components.

The publication DE 12 22 643 B discloses a plate element which is prefabricated in a concrete factory. The plate element contains in the plan view of its surface at least one hollow body region with hollow bodies contained therein. There are clamping elements or reinforcing mats cast in the lower and upper ceiling, which extend at right angles to each other in two directions.

It is an object of the present invention to provide an improved plate element that is gentle on materials, lightweight and stable and inexpensive to produce.

This object is achieved by a plate element and in particular by a ceiling element according to claim 1.

In the context of this application, the term "lattice-shaped" arrangement of clamping elements is to be understood as meaning a structure in which these elements intersect at one or different angles, which are not necessarily right. The clamping elements do not have to be rectilinear, but can also be curved, for example in the case of geometrically demanding plate geometries, e.g. circular arc, parabolic, eight-shaped or similar be laid to meet the corresponding load case.

The invention is based on the assumption that clamping elements guided over hollow body regions allow only limited prestressing due to the reduced material. In addition, a geometric problem arises because the space for receiving these elements is severely limited. So far so far a laying was possible, therefore, the combination of hollow body areas and bias does not necessarily lead to improved performance of the plate member. By too high a bias in these areas, the plate element can even be damaged and thus made unusable.

An essential point of the present invention consists first of all in the particularly reinforced support strips which connect individual support areas of the plate element to one another. This makes possible a hybrid combination of hollow body regions and prestressed regions of a plate element, which enhances the optimizing effect of both reinforcements in a technical, economical and ecological manner.

The example of the "limp reinforced" flat cover known approach to use entire modules with hollow bodies to reduce a ceiling own weight, can also be transferred to prestressed ceilings, in which compensated either only the own weight, or the entire loads by tensioning cable become. In doing so, the technical advantages of both methods can be combined and the weight reduction of the blanket can be increased compared to slackly reinforced, solid concrete floors or prestressed ceilings. The loads acting on the vertical elements such as columns, walls and foundations of a supporting structure are thus additionally reduced. At the same time, the use of material on tensioning cables and anchor heads is optimized, especially since the additional weight of the ceiling, which is reduced by between 25% and 30%, directly influences the required tensioning cable cross-section directly. Furthermore, the required concrete volume is reduced and the deformation of the ceiling is additionally minimized.

Depending on the floor plan and column grid, a planner has various options for arranging the cables. So he can choose a surface preload in which the cables are evenly distributed over the ceiling length and width. Another option is provided by the support strip bias, in which the cables are arranged in a concentrated manner in the zones running over the supports in orthogonally arranged bands. But it can also be a combination of both arrangements can be selected, in which in one direction surface, in the other one works in support strips.

A further reinforcement of the plate element according to the invention is achieved in that in the lateral view, the clamping elements are wavy laid in the plate member, and are supported on at least one latticework of rods with hollow bodies held therein, whose respective height is adapted to the waveform. Since the lattice derives the forces introduced by the clamping element past the cavities, they are protected from destruction. This is a hitherto unknown Spannelementführung and thus bias across hollow body areas away possible.

Preferred developments of the inventive plate element are specified in the subclaims and relate to types of reinforcement of the element in surface, Stützstreifen- and combined bias.

In the case of surface preload, a support strip preferably comprises at least one solid material region, via which loads introduced can be reduced. In order nevertheless to obtain a particularly light construction, it is preferred that laterally adjacent fields of the latticed structure form at least one elongated carrier strip with hollow body regions, which is arranged between two support strips.

In the case of the support strip bias, however, additional clamping elements for reinforcing the plate element are preferably provided in the longitudinal direction of a support strip. These clamping elements need not necessarily run laterally of the strip. In particular, they can be arranged distributed over the width thereof or lie only in its middle region. These additional clamping elements can also be designed comparatively stronger than others.

Alternatively or additionally, the clamping elements extending in the longitudinal direction of a support strip may themselves be reinforced, e.g. have a larger cross-section or a tensile material stronger than the other clamping elements. To reduce weight, a support strip may comprise at least one hollow body region.

In the case of a combined surface and support strip bias, for example, additional clamping elements may be provided within a support strip of solid material, while another support strip is reinforced only laterally and having hollow body portions. To further reinforce the support strip additional clamping elements can be provided which are distributed over its width or even run in its middle. If these clamping elements overlap hollow body regions of the support strip, they are provided with a lower preload. A weight reduction of the plate member can be achieved by supporting strips which extend in grid structure between the support strips.

In each case results in a particularly simple design and unidirectionally resilient plate element, when its lattice-shaped structure forms a grid of rectangular fields. Depending on the application, however, any other structure may be provided which consists of rectilinear or curved clamping elements, which intersect at a certain or several different angles.

It is preferred if the bars of the latticework are arranged slightly obliquely with respect to a normal of the surface of the plate element. Such designed modules thus compensate for a caused by the hollow body local reduction of the transverse force capacity of the ceiling cross-section. In addition, these bars can record the possibly generated in the concrete by the bias voltage local parasitic voltages perpendicular to the ceiling plane.

Even in the zones occupied by the tensioning cables, where the cables in the lower area of the ceiling cross section run parallel to the ceiling plane, additional modules can be installed if required. These are positioned by means of a spacer at a suitable distance to the tensioning cables and above them, depending on the standards and manufacturer's instructions for the minimum concrete sheathing of the cables. This reduces but possibly the usable hollow body diameter.

Lateral strips of the hollow body areas can still be reinforced by the latticework has support rods which protrude in the longitudinal direction over a receiving area for hollow body, and over which the clamping elements are laid. The lateral support can thereby still be improved by individual lattice works of rods are held with held therein hollow bodies to each other so that overlap their mutual support rods each other. At the same time, a reinforcement extending in the longitudinal direction over at least two latticeworks is created.

Depending on static specifications, however, it may also be preferred for lattice structures to have receiving regions which do not contain hollow bodies and over which the clamping elements are laid. As a result, an extremely flexible reinforcement of the plate element is also possible over regions which contain hollow bodies but, despite existing surface or support strip prestressing, require additional reinforcement.

Preferably, the plate element according to the invention should be used as a ceiling element, since just occurring there loads require a low weight and a high load capacity of the ceiling construction. However, its use is not limited to this, because it can also be used in any other application form, where particularly lightweight and at the same time very stable elements are required. This is not only the case in housing and office (high) construction, but also includes in particular power plants, bridges, dams and the like. one.

The above object is also achieved by a method of manufacturing a plate member according to claim 14.

An essential point of the inventive method consists in its simple feasibility both in the classical Ortbetonanwendung as well as in prefabricated Elements made in a precast concrete factory. The application of this method is conceivable both for use with concrete of conventional composition and quality, as well as for concrete of alternative mixture and conception, such as lightweight concrete and fiber concrete. Lattices with hollow bodies held therein are preferably delivered as modules.

These modules are installed directly between the lower and upper flared reinforcement in the zones of the ceiling not occupied by the tensioning cables. If there is no loose reinforcement in the zones occupied by the modules, the modules are placed directly on spacers that rest on the formwork. This is advantageous in that the ceiling cross-section can be better exploited in favor of the modules due to the absence of the upper and / or lower flaccid reinforcement layers. Taking into account the required minimum lower and upper concrete cover of the modules, larger hollow bodies can be used as a result.

In the case of surface or support strip prestressing, tension elements can additionally reinforce the plate element, which extend over hollow body regions. These elements need not have the basic tension of the surface or the support strips, but may be biased weaker. A flaccid reinforcement is then no longer absolutely necessary, so that a greater distance between modules and surfaces of the plate element can be used to accommodate the clamping elements. At the same time, the modules can serve as support for the pretensioning cables. In such a case, graduated size modules are selected according to the geometric shape of the tensioning cables and placed under the tensioning cables in the areas where the tensioning cables are located in the upper area of the ceiling section. This can be additional Occupy surfaces with modules and further optimize weight savings, as well as save conventional support aids. If necessary, the geometry of the modules used can be adapted to the conditions and specific requirements of the tensioning cables.

Preferably, the at least one tensioning element is placed on support bars of the latticework, which protrude in the longitudinal direction over a receiving area for hollow body. As a result, respective end regions of the latticework can be additionally reinforced, since there no hollow bodies come to rest.

In an advantageous manner, at least two latticeworks are laid in such a way that their respective support bars overlap. Thus, on the one hand the clamping elements are supported more. In the case of ceilings where the slack reinforcement is completely omitted, or which is installed locally only in certain areas of the ceiling, or where only minimal slack reinforcement is required, the presence of the modules will have an effect insofar as the lower and the lower reinforcement upper longitudinal bars of the modules can be regarded as a flabby additional reinforcement. As a result, the minimum additional reinforcement can be reduced at least in the reinforcement direction of the modules and the function of the crack reinforcement can be partially or completely taken over by the modules. In order for this to be possible, it must be ensured that the projections of the longitudinal bars of the modules are stretched by an overlap measure defined by the standards and are subsequently superimposed. This will ensure the continuity of the reinforcement required by the standards.

Figur 1

den schematischen Aufbau eines erfindungsgemässen Plattenelements mit Flächenvorspannung in einer Draufsicht auf seine Oberfläche;

Figur 2

den schematischen Aufbau eines erfindungsgemässen Plattenelements mit Stützstreifenvorspannung in einer Draufsicht auf seine Oberfläche;

Figur 3

eine Seitenansicht des ersten und zweiten Platten- elements mit einem Verlauf eines Spannelements ü- ber Gitterwerke mit darin gehaltenen Hohlkörpern;

Figur 4

ein erfindungsgemässes Gitterwerk mit darin gehal- tenen Hohlkörpern und überstehenden Stäben, und

Figur 5

eine um die überstehenden Stäbe überlappend ange- ordnete Kombination aus zwei Gitterwerken der Fi- gur 4.

The invention will now be described by way of example, with reference to the appended drawings. The same or equivalent parts are provided with the same reference numerals. Show it:

FIG. 1

the schematic structure of an inventive plate element with surface bias in a plan view of its surface;

FIG. 2

the schematic structure of a novel plate member with Stützstreifenvorspannung in a plan view of its surface;

FIG. 3

a side view of the first and second plate element with a profile of a clamping element about lattices with held therein hollow bodies;

FIG. 4

a latticework according to the invention with hollow bodies and protruding rods held therein, and

FIG. 5

a combination of two lattices of FIG. 4 overlapping the projecting bars.

The FIG. 1 The element 10 comprises hollow body regions 20 and supporting regions 30. In this example, orthogonally arranged clamping elements 40 form a grid-shaped structure 50, the respective fields 51 of which are the regions 20 and 30 limit. Laterally adjacent fields 51 form support strips 60, which connect the support areas 30 across fields 51 away from each other, these fields are designed to reinforce the support strip as solid material areas. On the other hand, laterally adjacent fields 51 form rows of elongated carrier strips 80 with hollow body regions 20, which are surface-tensioned via the clamping elements 40. Such a plate element 10 is preferably used as a ceiling element which is mounted in the support areas 30. In conjunction with the surface preload on the latticework 50, the solid support strips 60 provide sufficient stability for the intervening support strip 80 so that a light as well as sustainable ceiling element is created. By the right angle laying of the clamping elements 40 at the same time a simple and cost-effective production of the element 10 is ensured.

The FIG. 2 shows the schematic structure of a novel plate member 10 'with support strip bias in a plan view of its surface 11'. The element 10 'again comprises support and hollow body regions 20 and 30. Here, too, orthogonally extending clamping elements 40 form a grid-shaped structure 50 whose fields 51 delimit the regions 20 and 30. However, along support strips 60 that are orthogonal to each other across the plate member 10 ', the tension members 40 are reinforced, in this example, doubled. For reinforcement but also a larger cross-section and / or a more tensile material of the clamping elements can be provided. The support strips 60 are thus reinforced so that they can also comprise hollow body portions, which make the element 10 'lighter. By reinforcing the support strips 60, carrier strips 80 can be provided with large-area hollow body regions 20 which extend vertically and horizontally between the support strips 60. Although all here possible fields 51 are performed with hollow body portions 20, with such an element 10 'so that not only a weight but also a maximum carrying capacity is achieved. Again, the right angle laying the clamping elements 40 makes the simple and inexpensive production of the element 10 'possible.

The FIG. 3 shows a side view of the first and second plate member 10, 10 'with a profile of a clamping element 40 via lattices 90 with held therein hollow bodies 21. The size of the latticeworks 90 is chosen so that they specify the desired course of the clamping element 40. The latticeworks are constructed of rods 91, whose example, approximately trapezoidal frame on the one hand a particularly high stability on the other causes a particularly high power dissipation of the bias of the clamping element 40 in the material inside. The clamping element 40 rests on longitudinal bars 91 of the latticeworks 90, which extend perpendicular to the plane of the page. These rods 91 have a reinforcing effect corresponding to that of a reinforcement 100 and may even replace the reinforcement 100 under the circumstances to be described below. The combination of grids 90 and clamping elements 40 makes a bias in hollow body portions 20 of the plate elements 10, 10 'of FIGS. 1 and 2 and thus a reinforcement of the element 10, 10 'possible.

The FIG. 4 shows a grid according to the invention 90 with held therein hollow bodies 21 and projecting rods 92 which project beyond receiving areas 93 for the hollow body 21. The only example in FIG. 3 Although shown clamping element 40 may be laid at any desired location on, for example, the uppermost longitudinal bar 91 of the latticework 90. It is advantageous, however, to guide this over, for example, the uppermost support rod 92 of the latticework 90 at one or the other end of the latticework 90, since these ends are filled by solid material, which allows an even higher bias and thus gain. Of course, it is also possible to remove individual hollow bodies 21 from the latticework 90 in order to create solid material zones at this or at these locations, in which a targeted reinforcement by means of particularly highly tensioned elements 40 is provided.

The FIG. 5 Finally, a combination of two latticeworks 90 overlapping the projecting bars 92 shows FIG. 4 , Due to this overlap, all the longitudinal bars 91 of both latticeworks 90 act like the correspondingly aligned reinforcements 100 in FIG FIG. 3 , At the same time, the overlapping bars 92 provide a more stable support for the tensioning cable 40 also shown there, when it is laid over these rods 92.

As a result of the measures proposed according to the invention, a targeted reinforcement of a conversion element is possible depending on the intended use. The plate element according to the invention is significantly more load-bearing and at the same time lighter than a known plate element. The simple construction allows at the same time a cost-effective production. Due to its performance, it should preferably be used as a ceiling element that carries across wide areas.

Claims (16)

1. A prestressed slab element (10), in particular a concrete slab element, produced by the site-mixed concrete method or prefabricated in a concrete factory, which in the plan view onto its surface (11) comprises at least one hollow body zone (20) with hollow bodies (21) contained therein and at least one support zone (30) for supporting or holding the slab element (10) without a hollow body (21), as well as tensioning elements (40) for reinforcing the slab element (10), which are each laid through the slab element (10) and which form a latticed structure (50), wherein individual fields (51) of this structure (50) establish a support zone or hollow-body zone (20, 30), and laterally adjacent fields (51) of the latticed structure (50) form at least one oblong support strip (60), which connects together individual support zones (30), and which is designed reinforced, characterised in that, in the side view of the slab element (10), the tensioning elements (40) are laid in corrugated form in the slab element (10) and are supported on latticeworks (90) comprising rods (91) with hollow bodies (21) contained therein, the respective height whereof is matched to the corrugated shape in such a way that the heights of the latticeworks (90) stipulate the corrugated course of the tensioning elements.
2. The slab element (10) according to claim 1, wherein at least one support strip (60) comprises at least one solid-material zone (70).
3. The slab element (10) according to claim 1 or 2, wherein laterally adjacent fields (51) of the latticed structure (50) form at least one oblong bearing strip (80) with hollow-body zones (20), which is disposed between two support strips (60).
4. The slab element (10) according to any one of the preceding claims, wherein additional tensioning elements (40) are provided in the longitudinal direction of at least one support strip (60).
5. The slab element (10) according to claim 4, wherein additional tensioning elements (40) are disposed distributed over a width of at least one support strip (60) or lie in its central zone.
6. The slab element (10) according to any one of the preceding claims, wherein tensioning elements (40) reinforced with respect to other tensioning elements (40) are provided in the longitudinal direction of a support strip (60).
7. The slab element (10) according to any one of the preceding claims, wherein a support strip (60) comprises at least one hollow body zone (20).
8. The slab element (10) according to any one of the preceding claims, wherein the latticed structure (50) forms a grid of rectangular fields.
9. The slab element (10) according to claim 8, wherein the rods (91) of the latticeworks (90) are disposed running slightly obliquely with respect to a normal of the surface (11) of the slab element (10).
10. The slab element (10) according to claim 8 or 9, wherein the latticework (90) comprises support rods (92), which in the longitudinal direction project beyond an accommodation zone (93) for hollow bodies (21), and over which the tensioning elements (40) are laid.
11. The slab element (10) according to any one of claims 8 to 10, wherein the latticeworks (90) comprise accommodation zones (93) which contain no hollow bodies (21) and over which the tensioning elements (40) are laid.
12. The slab element (10) according to any one of claims 8 to 11, wherein individual latticeworks (90) comprising rods (91) with hollow bodies (21) contained therein are disposed with respect to one another in such a way that their two-sided support rods (92) mutually overlap.
13. Use of the slab element (10) according to any one of the preceding claims as a cover element.
14. A method for producing a slab element (10), in particular a concrete slab element, according to any one of claims 1 to 12, with the steps:

    - insertion of a lower, slack reinforcement (100) on spacers of a formwork;

    - insertion of at least one latticework (90) comprising rods (91) with hollow bodies (21) contained therein onto the reinforcement (100) or onto the spacers;

    - insertion of at least one tensioning element (40) onto the at least one latticework (90);

    - insertion of an upper, slack reinforcement (100) onto the at least one latticework (90) or onto spacer baskets;

    - introduction and initial curing of a first concrete layer for safeguarding the hollow bodies (21) against uplift;

    - introduction and final curing of a second concrete layer to produce the final thickness of the slab element (10);

    - tensioning of the tensioning elements (40) to reinforce the slab element (10)
15. The method according to claim 14, wherein the at least one tensioning element (40) is laid on support rods (92) of the latticework (90), said support rods projecting in the longitudinal direction beyond an accommodation zone (93) for hollow bodies (21).
16. The method according to claim 15, wherein at least two latticeworks (90) are laid in such a way that their respective support rods (92) overlap.

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