DE20010770U1 - Highly insulating reinforcement cage with heat-insulating reinforcement elements - Google Patents

Description

Engineering office thermal insulation Dipl.-Ing. (FH) Jörg Dießler

Description

Areas of application of the invention

The invention relates to a highly thermally insulated reinforcement cage, which can create a thermal separation between two concrete components and a statically effective connection between them. This reinforcement cage is used to connect cantilevered balcony slabs, consoles, wall panels or loggia walls made of reinforced concrete. Furthermore, the highly thermally insulated reinforcement cage can be used to create rigid and thermally separated connections such as reinforced concrete walls to floor slabs and reinforced concrete parapets to ceiling slabs.

State of the art

The rigid, thermally insulated concrete connections described in DE 3739967 and EP 0332954 Al solve the problem of the risk of corrosion caused by condensation on the reinforcement. In both patents, it is characteristic that the connection between the concrete parts is made of normal structural steel (BSt 500). In the connections mentioned, the reinforcing iron extends into both the heated ceiling area and the cantilevered slab area exposed to the outside air. In this way, a constant flow of heat flows through the reinforcing iron when there are corresponding temperature differences. At 60 W/m K, structural steel has a comparatively high thermal conductivity. In order to reduce these heat losses through the reinforcing steel somewhat, reinforcement cages are on the market from Schock Bauteile GmbH, which uses stainless steel reinforcement elements in the area of rigid foam insulation. Depending on the alloy grade, stainless steel has a thermal conductivity of 15-45 W/m K. Due to the use of stainless steel and increased technical effort (welded joints), such reinforcement cages are comparatively expensive.

Problem

Due to the high thermal conductivity of structural steel (60 W/m K) or stainless steel (15-45 W/m &khgr; K), there is insufficient thermal separation between interior and exterior components. The result is increased energy losses, which on the one hand lead to higher heating costs and on the other hand to increased COx emissions, which are harmful to the climate. Furthermore, the steel reinforcement elements, which conduct heat well, are the cause of the connected interior ceiling surfaces cooling down in winter, which under unfavourable conditions can be prone to condensation and thus the formation of mould. With the introduction of the Energy Saving Ordinance 2000 in Germany, so-called thermal bridges are becoming even more important, as they must be included in the energy balance and compensated for by additional insulation of other parts of the building.

The second problem with thermally insulated reinforcement cages is the relatively high acquisition costs, which have a negative impact on the total construction costs.

Engineering office thermal insulation Dipl.-Ing.(FH) Jörg Dießler

Solution and benefits

The problems described above are solved by the highly heat-insulating reinforcement cage listed in claim 1. The reinforcement elements made of steel or stainless steel that are commonly used today are replaced by heat-insulating tension members (1) or heat-insulating compression members (2). The solution was to consistently use the advantageous properties of glass. When using glass fibers, the thermal conductivity of the tension member (1) is only 0.5-0.6 W/m K. The thermal conductivity of the compression member (2) made of glass is only 0.70-0.80 W/m K. Comparable reinforcement elements made of stainless steel have an average thermal conductivity of 46 times (average 28 W/m K) and reinforcement elements made of structural steel (BSt500: 60 W/m K) even 100 times . The tension member (1) can make optimal use of the tensile strength of glass fibers, for example, which is three times higher than that of steel, and the compression member can make optimal use of the high compressive strength of glass. The higher stress utilization of the heat-insulating reinforcement elements (1,2) enables a reduction in the statically effective material cross-sectional areas. In the tension member (1), the cross-sectional area can be reduced by 40-50% compared to steel, and in the compression member (2) by 30-40%. These reduced material cross-sections can further reduce the energy losses caused by heat conduction.

A second advantage of the invention is the significantly lower manufacturing costs of the highly heat-insulating reinforcement cage. I expect a reduction in manufacturing costs of around 30-40 % compared to a reinforcement cage with stainless steel reinforcement. The reasons for this are the significantly lower material costs of glass and fiberglass, as well as the simplified construction of the reinforcement cage itself.

EN 2Ü(ra 77&Oacgr;

Claims (11)

1. Highly heat-insulating reinforcement cage, characterized in that heat-insulating tension members ( 1 ) are used to absorb tensile forces and heat-insulating compression members ( 2 ) are used to absorb compressive forces, in conjunction with an insulating body ( 4 ). 2. Highly heat-insulating reinforcement cage according to claim 1, characterized in that the tension member ( 1 ) consists of a bundle of non-metallic fibers (e.g. made of glass, carbon, quartz-silica, etc.). The fibers are aligned in the direction of the longitudinal axis of the bundle. The individual fibers are connected to one another by an alkali-resistant matrix. 3. Highly heat-insulating reinforcement cage according to one of claims 1-2, characterized in that the bundle of non-metallic fibers is enclosed in the area of the concrete by a self-interlocking sleeve (6, Fig. 3). The sleeve is connected to the fiber bundle in a material-locking and form-fitting manner. The sleeve ( 6 ) consists of a metallic material. 4. Highly heat-insulating reinforcement cage according to claim 1, characterized in that a one-piece pressure member ( 2 ) consisting of a mineral glass or a glass-containing material is used to absorb compressive forces. 5. Highly heat-insulating reinforcement cage according to one of claims 1-4, characterized in that the pressure element ( 2 ) is formed in the area of the insulating body ( 4 ) by two intersecting flat cuboids ( Fig. 4). In the case of highly stressed pressure elements ( 2 ), the pressure element ( 2.1 ) in the area of the insulating body ( 4 ) consists of four intersecting flat cuboids ( Fig. 5). These flat cuboids penetrate the insulating body ( 4 ) and the hollow profile ( 3 ). 6. Highly heat-insulating reinforcement cage according to claim 4, characterized in that a kink-proof, flat circular cylinder made of the same material is arranged in the middle of the pressure member ( 2 ). 7. Highly heat-insulating reinforcement cage according to one of claims 1-6, characterized in that the pressure member ( 2 ) in the region of the concrete is formed from a solid hemisphere of the material according to claim 4. 8. Highly heat-insulating reinforcement cage according to one of claims 1-3, characterized in that a tension member ( 5 ) penetrates the insulation body ( 4 ) at an angle and is anchored in the concrete in order to absorb transverse forces. 9. Highly heat-insulating reinforcement cage according to one of claims 1-8, characterized in that the insulating body ( 4 ) is surrounded by a rectangular hollow profile ( 3 ). 10. Highly heat-insulating reinforcement cage according to claim 9, characterized in that the hollow profile ( 3 ) consists of a fiber-reinforced plastic. 11. Highly heat-insulating reinforcement cage according to one of claims 1-10, characterized in that the hollow profile ( 3 ) is foamed with an insulating material which does not exceed the thermal conductivity of 0.030 W/m K and which forms an inseparable material and form-fitting connection with the reinforcement members ( 1 , 2 , 5 ) and with the hollow profile ( 3 ).