EP0219792B2 - Heat-insulating load-bearing construction element - Google Patents

Abstract

With the construction element (1), the heat-insulating layers (5, 9) in the floor (2) and the wall (8) can be closed together. In this arrangement, the construction element equipped with a load-bearing skeleton and a heat-insulating layer can absorb the loads taking effect in walls up to 1.2 N/mm<2>. The skeleton runs in a zigzag-like manner through the heat-insulating material and possesses upper and lower booms covering the latter in places. <IMAGE>

Description

The present invention relates to a heat-insulating, load-bearing component

A thermal bridge is a local area through which increased heat can flow away within a structure that is well insulated per se. The better the thermal insulation of the corresponding component, the more problematic such thermal bridges are, because they not only reduce the good average k-value of the component, increase energy loss and there is a risk that the local surface temperature will reduce the warm side Location of the thermal bridge separates surface condensate and subsequently discoloration and mold formation occurs. Such weak points must be avoided through constructive measures. Through existing standards, e.g. Recommendation SIA 180/1, it is accordingly required that thermal bridges be avoided or that these may have to be compensated for by special measures such as increased thermal insulation and careful connection details (see Art. 4.5 of recommendation SIA 180/1).

In recent years, the requirements for the thermal insulation of external components have increased significantly. Today heat transfer coefficients of K 0.40 W / m ² K are aimed for, which is possible with the current state of the art in the ideal cross section within the wall.

In this context, e.g. at the base of the wall in the transition area from unheated to heated floors, e.g. Problems from the basement to the ground floor, because thermal insulation is particularly important here. The conventional solutions, in which the rising masonry is placed on the uninsulated concrete cover or the concrete outer wall, inevitably lead to a thermal bridge along the entire length of the base of the wall, because the connection of the thermal insulation layers in the floor and wall is not guaranteed.

It must be noted that the mean vertical stresses acting in the base of the wall can be up to 1.2 N / mm ² from the weight of the possibly multi-storey structure. It must also be ensured that horizontally acting forces, for example due to ground vibrations, wind, etc., can also be reliably transmitted.

Various design measures have been proposed to overcome the problems described above. This includes e.g. an extension of the thermal insulation layer of the outer wall to the area under the terrain. This usually requires a double-shell formation in the upper area of the wall (cf. R. Martinelli + K. Menti: "Improved execution of double-shell masonry in the area of the masonry foot" in the Swiss engineer and architect 41/80). Such a solution is associated with a high amount of additional construction work, which leads to a marked increase in costs. It is also possible to separate the basement ceiling from the outer walls (see SIA Documentation 80: Energy in Building Construction, April 1985). However, this solution leads to an inefficient ceiling system. The soft ceiling edge is unsuitable for absorbing vertical loads from outer walls. In the case of unheated basements, the basement ceiling must also be provided with thermal insulation at the bottom.

Furthermore, it was also proposed to install a horizontal thermal insulation layer between the basement ceiling and the rising masonry, which e.g. consists of foam glass. This solution is not satisfactory because the thermal insulation layer may be subjected to far less stress than the supporting walls resting on it. Foam glass, which as a thermal insulation material has a relatively high compressive strength, is also a very brittle material and must be processed with great care.

Finally, DE-A-30 35 931 discloses a heat-insulated component that can be installed as a wall element. However, this could only be loaded centrically and is therefore not suitable for absorbing the wall forces that occur in load-bearing masonry.

In spite of the numerous suggestions for preventing thermal bridges per se, their removal in the area of the masonry base and elsewhere has so far generally been dispensed with because the large technical and financial additional expenditure could not be achieved, or the solution proposed above could not be achieved for other reasons is feasible.

The purpose of the present invention is now to provide a device for preventing thermal bridges which can be used without having to accept the constructional and financial disadvantages described above.

According to the invention, the component has the features of claim 1.

However, in order to prevent impermissibly high edge pressures in the connecting elements due to the narrow web due to the heat transport to be avoided, an upper and a lower flange are also provided, which run perpendicular to the web and together with the latter in cross-section the profile of a double-T beam exhibit. Upper and lower chords cover the core surfaces in some areas. This means that it is also protected against mechanical damage during storage and transport largely protected.

The skeleton can also have several band-shaped, in regular order e.g. have webs which are interleaved or formed only in sections and pass through the core. In this case, at least one or webs and / or web sections is then provided with an upper and / or a lower flange, the upper and lower flange covering regions of mutually opposite surfaces of the core.

The skeleton is made of a non-brittle mineral-based material. A mineral fiber composite material is preferably used. For certain special applications it can be advantageous to provide an embodiment of the component with a steel skeleton. Although such a skeleton has a comparatively large heat transfer, the improved load-bearing behavior will be decisive in the case of highly stressed components such as supports or balcony connections.

The component according to the invention enables a perfect technical solution with simple means and low costs. It can be used as a load-bearing and heat-insulating component e.g. be bricked up on the basement ceiling as the first layer of the rising masonry. As a result, it lies within the structural strength of the sub-floor, so that there is no change of material when the interior walls are plastered.

However, the use of the component is by no means limited to the base of the wall, although its advantages are particularly effective there. It can be used wherever excessive heat flow should not only be prevented across the wall, but mainly in the plane of the wall or the component itself.

Further advantages of the component according to the invention are e.g. in that it can be easily processed. The elements can be bricked in lengths that correspond to the multiple of the brick format as the first layer. Through the course of the upper and lower chord, recesses are arranged in the cover layers, into which the masonry mortar can penetrate, so that a full contact is guaranteed over the entire length of the element. The same recesses also form an interlocking with the ceiling and masonry.

Furthermore, the cross-section and length of the element are matched to the usual brick formats. This enables economical production as standard elements. Furthermore, the elements can easily be cut to the desired length on site. When using a closed-cell thermal insulation material, the absorption of moisture is prevented.

The invention is explained in more detail below on the basis of the exemplary embodiments illustrated in the drawings.

• Fig. 1 schematisch einen Querschnitt durch einen Gebäudeteil, bei welchem eine Wärmebrükke im Bereich des Mauerfusses durch das erfindungsgemässe Bauelement unterbrochen ist,
• Fig. 2 eine Ansicht eines bevorzugten Ausführungsbeispiels des erfindungsgemässen Bauelements,und
• Fig. 3 schematisch das Skelett des Bauelementes von Figur 2.

Show it:

• 1 schematically shows a cross section through a part of the building in which a thermal bridge in the area of the base of the wall is interrupted by the component according to the invention,
• 2 shows a view of a preferred exemplary embodiment of the component according to the invention, and
• 3 schematically shows the skeleton of the component from FIG. 2.

Figure 1 shows a cross section through part of a building, 1 the component according to the invention, 2 a basement ceiling, 3 a basement wall, 4 the surrounding soil, 5 the thermal insulation layer on the ceiling, 6 the floor shell, 7 the outer shell and 8 the inner shell of the rising masonry. A heat insulation layer 9 is located between the outer and inner shells 7, 8.

So that there is no gap between the heat insulation layers 9 and 5, through which heat flows out of a room 10 through the inner shell 8 and the basement ceiling 2 into the basement or the basement wall 3, the component according to the invention, as indicated in the figure, used to interrupt the otherwise existing thermal bridge. The dashed section of the arrows makes it clear at which point the heat flow from the room 10 would be significantly increased without the use of the component 1.

FIGS. 2 and 3 show a view of the component 1 according to the invention (FIG. 2) or a view of the same component in which the core 11 has been removed from preferably closed-cell thermal insulation material (FIG. 3).

12 denote the one end of the web 13 passing through the core 11, and 14 the one end of the upper flange 16 assigned to the web 13 and 15 the one end of the lower flange 17 assigned to the web 13.

The upper and lower chords 16, 17 serve to ensure that no excessive pressures occur on the connecting surfaces of the masonry that are in contact with the component. The web is of course designed according to the masonry loads to be removed, but as narrow as possible so that the amount of heat flowing through it can be kept to a minimum.

It should be noted, however, that the upper and lower chord that reduces the surface pressure in the connecting surfaces should not be too strong, because the wall loads are not transferred to the web of the component without straight through the masonry and the bedding mortar over the element; Experiments show that a rigid formation of the upper and lower chord would only give rise to shear bridges at the edge of the web.

Tests have shown that the required width of the upper or lower flange is generally approximately 50% of the height of the associated web; however, it must also be adapted to the mechanical properties of the adjoining element.

It is also advantageous to cover the longitudinal edges of the core 11 with strips 19. This protects the core against mechanical damage. In a preferred embodiment, the strips are located on the surfaces of the core covered by the upper and lower chord and are formed in one piece with the upper and lower chord. This creates areas on all sides of the skeleton (apart from the ends of the component) in which the surfaces of the core are not covered. These areas should not be unnecessarily reduced by over-wide top and bottom belts.

If the component is bricked up, superfluous mortar should penetrate into these areas. After the mortar has hardened, the masonry is interlocked with the component, which ensures that shear forces acting between the latter are reliably transmitted.

It also ensures that the component lies evenly on its supporting or supporting lower or upper chord. This results in a uniform load in the belts.

As FIG. 3 shows, the web 13 running back and forth between the longitudinal sides of the component has sections 18 which run parallel to the latter in the region near these longitudinal sides. This makes it possible that the upper and lower chord can always protrude from both sides of the web and thus the connection between the upper and lower chord is essentially only subjected to pressure and thus no impermissible bending moments are generated in the web itself. Since the resultant of the wall load often runs eccentrically in the wall, the zigzag-shaped web ensures that the wall load is properly absorbed.

The embodiment of Figures 2 and 3 has only one web, it is easily conceivable that for special applications several webs, e.g. are intertwined in a regular sequence. It is also possible to provide webs formed only in sections. It may make sense not to provide all the webs or sections with an upper and / or lower flange, since the same conditions do not exist in the various connecting surfaces or the free areas should not be too small for forming the interlocking with the masonry.

In a further exemplary embodiment, the core of thermal insulation material is kept uncovered by the skeleton over the entire surface of a long side of the element. This can also be achieved retrospectively in the case of an existing component in that the longitudinal side mentioned is covered with a strip of thermal insulation material, the corresponding strips 17 (FIG. 2) then also having to be covered by the upper and lower flange. The thickness of the strip is preferably 1 cm.

This prevents a plaster layer from being brought over a finished wall or wall section, which bridges a long side of the element in the sense of a thermal bridge that is not pronounced but still exists. The plaster layer is then interrupted by thermal insulation material in accordance with the dimensions of the installed elements; However, it is easy to see from Fig. 1 that if the element is installed accordingly, e.g. a base shell 6 extends far enough beyond the element 1 so that a plaster layer on the long side of the element can be dispensed with.

For increased load-bearing capacity of the web 13, its cross-section is constricted in such a way that its minimum thickness is approximately half the web height and the cross-section comes close to the outline of an X-shape. As a result, critical tensile stresses at the skeleton material are avoided at high loads and corresponding bending of the web.

Claims (10)

1. Heat insulating, load-bearing construction element with elongate extension and with an essentially rectangular cross-section, each element comprising a load-receiving bottom and cover surface as well as two lateral faces and being destined for integration into masonry to reduce the heat flux, whereby said construction element comprises a core of heat insulating material and a skeleton extending within this core, which skeleton comprises webs (13) arranged between said bottom and cover surface and extending continuously or with interruptions substantially over the whole length of the element, said webs comprising sections (18) positioned at either side near the lateral faces, as well as sections which extend obliquely to the longitudinal direction of the element in such a way as to form a continuous band which zigzags between opposed lateral faces, whereby the webs (13) are part of a skeleton that partly covers the core (11), and which serves to transmit wall forces between cover and bottom surface.

2. Construction element according to claim 1, characterized in that the zigzagging web (13) in the sections (18) near the lateral faces extends parallel to the latter.

3. Construction element according to one of the preceding claims, characterized in that the skeleton is provided with an upper chord and a lower chord (16, 17) extending at the cover and the bottom surface of the element.

4. Construction element according to claim 1, characterized in that the skeleton comprises two pairs of lateral strips (19), one pair extending on both sides of the cover and one on both sides of the bottom surface in order to cover their lateral zones.

5. Construction element according to claims 3 and 4, characterized in that the upper or the lower chord (16, 17), respectively, are formed as one piece with the lateral strips (19).

6. Construction element according to one of the preceding claims, characterized in that recesses (20) are provided at the bottom and the cover surface to interconnect the element with layers of mortar adjacent to the cover and bottom surface.

7. Construction element according to claim 6, characterized in that the recesses (20) are formed by openings between the chords or the strips, respectively, (16, 17, 19) extending at the cover and bottom surface of the supporting members.

8. Construction element according to one of the preceding claims, characterized in that towards the lateral faces of the element the webs (13) are covered by heat insulating material.

9. Construction element according to claim 8, characterized in that towards one of the lateral faces of the element all parts (13, 16, 17, 19) of the supporting members are covered by heat insulating material.

10. Construction element according to one of the preceding claims, characterized in that the webs (13) have a cross-section which is constricted such that the minimal web thickness lies at about half the web height and increases towards the bottom and the cover surface.

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