FI85403C - Process for producing a plastic composite beam or pillar with the steel reinforcement - Google Patents

Abstract

The invention relates to a plastic composite beam or pillar (20) comprising a reinforced-plastic body (31) and steel reinforcements (30). The invention also relates to a method for manufacturing a steel-reinforced plastic composite beam or pillar, in which method the steel reinforcements (30) are placed in the beam or pillar (20) in connection with the manufacturing of the beam or pillar (20) by utilizing the pultrusion technique.

Description

85403

Method for the manufacture of a steel-reinforced plastic composite beam or column Förfarande för framställning av en plastkompositbalk eller -pelare med stälförstärkningen 5

The invention relates to a method for manufacturing a steel-reinforced plastic composite beam or column.

10 Beams and columns made of plastic composites are known from the prior art, in which, for example, fiberglass or carbon fiber has been used as reinforcement. Such known beams have not been rigid enough for all applications.

DE-A-1 956 826 discloses a beam structure with a steel reinforcement, in which the beam (or part of a beam) is produced by laminating the steel reinforcement inside the beam during its manufacture.

A disadvantage of this known method is that in the lamination the air bubbles tend to be trapped between the reinforcement and the reinforcing plastic, whereby there is a risk of the reinforcement and the reinforcing plastic layer separating from each other as a result of stress and thus a substantial deterioration of the beam strength. In addition, the method makes it difficult to produce products with a smooth outer surface without expensive molds. Mold costs are significant, as 25 full-length molds would have to be made for each purpose.

The pultrusion technique is known to produce profiles with different cross-sections, which are usually relatively small in size. Pultrusion products always consist of thin fibers bound by a binder plastic, which themselves do not have any bending strength. The pultrusion technique is described, e.g., in Encyclopedia of polymer science and engineering, volume 13, USA 1988.

It is an object of the invention to provide a plastic composite beam or column substantially thinner and stiffer than known beams.

In order to achieve the above and later objects, the method according to the invention is mainly characterized in that a plastic composite beam or column is manufactured by placing steel reinforcements in a beam or column using a pultrusion technique in connection with pultrusion.

The invention combines two quite different techniques and thus achieves a number of significant advantages. It is in this aggregation, i.e. the use of pultrusion technology, that the core of the invention is at stake. The advantages of the pultrusion technique in the production of a beam or column according to the invention are that the technique enables a beam structure with dimensional accuracy and as little reinforcement plastic as possible, which is nevertheless very strong and load-bearing. No air bubbles that impair strength can occur. At the same time, smooth surfaces that do not require surface treatment are achieved. There are no restrictions on the length of the beams. The technology further enables composite structures in which the flexural strength is further increased by a lightweight foam filling.

The beam according to the invention is substantially stiffer than the conventional beam due to the additional reinforcements.

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In a certain application, the cross-sectional area of the beam according to the invention can be dimensioned smaller than that of a known beam, whereby material is saved and thus also material costs are reduced, because the stiffness of the beam is increased due to additional reinforcements.

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The inner part of the beam or column can be filled with PUR, EPS or concrete filling to cross-sectional plate-like surfaces to prevent buckling under bending stress.

The invention also brings additional possibilities for use for plastic composite beams or columns due to their additional rigidity and that the steel parts allow the profiles to be fastened with screw joints. The solution according to the invention can replace e.g. similar reinforced concrete, wood or aluminum structures.

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The invention will now be described in more detail with reference to the figures of the accompanying drawing, in which Figure 1 schematically shows a straight beam or pillar, Figure 2 shows a cross-section DD of Figure 1 according to an embodiment and Figure 3 shows a cross-section according to another embodiment section DD from figure 1.

Figure 1 shows a straight beam or column 20 supported at its ends by supports 12. Additional reinforcements are indicated by dashed lines, indicated by reference numeral 30.

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In the example of the invention according to Figure 2, the plastic composite beam or column 20 comprises a reinforced plastic body 31 and a PUR (polyurethane) or EPS (cellular polystyrene) material as the inner material 32 of the beam. The plastic composite beam or -20 pillar 20 of the embodiment shown in Figure 2 is fabricated using the pultrusion technique such that steel reinforcements 30 are added to the plastic composite beam or pillar 20 during pultrusion.

Figure 3 shows a plastic composite beam or column 20 with steel reinforcements in the form of steel plates 40. In other respects, the plastic composite beam or column 20 corresponds to that shown in the other figures, such that the reinforced plastic body is indicated by reference numeral 31 and the inner part of the beam, which is made of EPS or PUR material, is indicated by reference numeral 32.

The invention has been described above only with reference to some preferred embodiments thereof. However, this is in no way intended to limit the invention to these examples only, but many modifications and variations are possible within the scope of the inventive idea defined by the following claims.

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Claims (3)

4 85403 A method of manufacturing a steel-reinforced plastic composite beam or column, characterized in that the plastic composite beam or column (20) is manufactured by placing steel reinforcements (30, 40) on a beam or column (20) using pultrusion technique in connection with pult rusion. Method according to Claim 1, characterized in that a rod (30), e.g. a brushed steel rod, is used as the steel reinforcement. Method according to Claim 1, characterized in that a steel plate (40) is used as the steel reinforcement. 15 5 85403