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The object of the invention is a load-bearing frame of a construction connector. The task of the construction connector containing a load-bearing frame according to the invention is to provide stable connection between a structure and a terrace slab or another construction element protruding outside the envelope of the structure. A connection with this connector type is usually used at the ceiling level of the structure.
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A range of solution related to load-bearing frame for reinforcing construction connectors are known, intended to connect the body of the building with an external element protruding outside said body, for example with a terrace slab. Such a connection is usually located on the level of a ceiling present inside the building. To provide such a connection, the connector usually has elements made of thermally insulating material within the area of the load-bearing frame, introduced into the frame space and intended to mitigate the negative impact of the formed thermal bridge.
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A thermal bridge is described as any location within the outer wall of a structure, through which heat can flow outside from the interior. Example locations where thermal bridges may be present include the aforementioned connections between a terrace slab and a ceiling, points inside a basement, window, sill, threshold and beam areas of a structure. Damp, mould and fungi appearing at such points may indicate the presence of thermal bridges at certain areas of the structure. For inspection purposes, such points are detected using non-destructive testing, using thermal imaging photographs taken outside the structure. Because of the reasons outlined above, thermal insulation elements, usually dedicated to a specific connector, are an important component of the construction connector design. Such elements are usually made of an insulating material, usually foamed polystyrene or rock wool. They decrease the loss of heat from inside the structure to the outside, mainly through the design elements of the connector.
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A range of load-bearing frame solutions for construction connectors is known. A solution known from the European patent disclosure
EP 1647643 presents a load-bearing frame of a construction connector connecting a structure with a construction element protruding outside the building envelope. An example of such element is a terrace slab. According to this known solution, the connector has a range of reinforcing bars transverse to the terrace slab connector, on the level of the building ceiling. These bars are finally placed within the building ceiling on one side and inside the terrace slab on the other. A connector according to this known solution includes an insulating body, from which the aforementioned reinforcing bars protrude on both sides.
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Another solution of a load-bearing frame for construction connector is disclosed in the European patent application number
EP 3613910 . According to this known solution, a load-bearing frame for a construction connector includes thermal insulation and at least one pair of load-bearing elements placed one above the other and includes a thermal insulation layer around these load-bearing elements and between them. The load-bearing frame of the connector according to this known solution includes thermal insulation with a top and a bottom fire protection layer. The load-bearing element is a section of a steel profile, to which steel reinforcing bars are attached on both ends, comprising extensions of said profile. A steel profile section free of said reinforcing bars is present between said reinforcing bars attached on both sides of the steel profile. The steel profile according to this known solution is an omega cross-section, open profile. One C-shaped steel reinforcing bar with two arms is attached to at least one end of this steel profile, at the bends of its arms. The reinforcing bar is welded to the omega cross-section steel profile, at the bends of said steel profile, between the arm of this steel profile bent outwards and the side wall of the ridge of this omega cross-section profile perpendicular to said arm. According to this known solution, both load-bearing elements are placed parallel one above the other in a pair of load-bearing elements with omega cross-section and oriented to each other with the backs of the steel profiles, such that the arms of both steel profiles bent outwards are in planes parallel to each other. The arms of the top and the bottom omega cross-section steel profiles are connected on both sides with U-shaped reinforcing bars, in the area of their bending into the U-shape, as well as with additional, spacer reinforcing bars. The area of steel profile with spacers in this known solution is a structural design in the same of a rectangular cuboid comprising the load-bearing frame. The construction connector in this known solution is thus a load-bearing frame with straight reinforcing bars on both sides of the load-bearing frame. The reinforcing bars protruding from the load-bearing frame on both sides are used to connect the reinforced concrete of the terrace slab with the reinforced concrete of the ceiling of the structure.
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According to another invention known from the European patent disclosure number
EP 4047147 , a load-bearing frame of a construction connector contains at least one pair of steel section profiles with omega cross-section one above the other, wherein two ends of a U-shaped reinforcing bar are attached to at least one omega cross-section steel profile, on both sides of the back of this profile. Said U-shaped reinforcing bars are an extension of the omega cross-section steel profile on both sides and perpendicular sections of a reinforcing bar connecting these two steel profile and maintaining the distance between said profile, as well as rigidity of the load-bearing frame, are also attached between these steel profiles. According to this known solution, two free ends of a U-shaped reinforcing bar are attached to each end of the steel profile. In the working position of the connector, each U-shaped bar covers the back of the steel profile to which it is attached with the free ends. Said steel profiles are omega cross-section open profiles. The U-shaped reinforcing bars are positioned in a plane parallel to the plane of the arms of the omega cross-section steel profiles, and thus differently than in the solution known from the European patent number
EP 3613910 . According to this known solution, each reinforcing bars is attached to the arms of one omega steel profile and to the walls of the backs of these profiles abutting said arms. In this known connector, in the pair of omega cross-section steel profiles, both profiles are positioned parallel one above the other and facing each other with their backs. According to this known solution, the outwardly bent arms of both steel profiles are positioned in planes parallel to each other. The connections between these profiles are provided as welded joints. The omega steel profiles together with the steel bars comprise a rectangular cuboid structure, described as a load-bearing frame in this patent disclosure. U-shaped steel profiles protrude from this load-bearing frame on both sides.
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With the progress in the field of non-destructive thermal quality control testing for external walls of structures, the related requirements also increase. The thickness of thermal insulating linings used on the outer walls of structures is increasing in response to this requirement.
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This results in an increase in expectations of the construction market, related to the limitations of thermal bridges, also arising in relation to the installation of terrace slabs to structures. The designs of construction connectors used for the purpose, known in the art, are not resistant enough so that their thickness can be increased in response to the increasing thickness of insulation of structure walls. It is thus impossible to increase the thickness of insulation present in load-bearing frames known in the art. It became necessary to develop a new design of a construction connector for this purpose. Thus, the task included the development of another connector variant, but using proven omega cross-section steel profiles.
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In the designs previously known in the art, the load-bearing frame for construction connectors includes at least four welded spacer bars between both omega cross-section steel profiles, placed one above the other, maintaining the system of two omega steel profiles in a structure similar to a rectangular cuboid.
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The term load-bearing frame used in this patent disclosure means a structure containing the top and the bottom omega profile connected using spacers, into a structure similar to a rectangular cuboid. To such a known load-bearing frame, straight or U-shaped reinforcing bars are welded, oriented outside with their arms or bends, towards the terrace slab and/or towards the building ceiling, as shown in the figures in the listed documents presenting the art of the invention.
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However, while increasing the length of such a load-bearing frame proportionally to the increasing thickness of thermal insulating elements placed inside the frame, it turned out that the existing structure of load-bearing frames according to the known solution loses its resistance and rigidity, thus requiring a significant increase of the number of such connectors along the connection length between the terrace slab and the building. However, the increase in the number of load-bearing steel frames results in an increased number of thermal bridges and a significant increase of thermal insulation of such a connection. It was found that the main path of heat leak are the steel elements present in the load-bearing frames of the disclosed connectors themselves. The load-bearing frame of a connector known in the art, adapted for example to the thermal insulation thickness of 80 mm, loses 10% of its load-bearing capacity if its length is increased for the use of 120 mm thick thermal insulation both in terms of its bending moment and the shear force. If 160 mm thick thermal insulation is used, namely if the frame is extended, the same known load-bearing frame loses almost 20% of the listed resistance parameters.
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The problem to be solved was to develop such a design change to the load-bearing frame of a construction connector that an increase in thermal insulation thickness, and thus an increased length of the load-bearing frame connecting the reinforcing bars for use of a thicker thermal insulation layer did not result in decreased resistance parameters of the connector, for which the load-bearing frame is of key importance. The term of length of the load-bearing frame of a connector should be understood here as the length of the frame design between the reinforcing elements attached to said frame on one and/or on the other side of the frame.
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Another problem to be solved was to ensure the design simplicity and flexible use of the connector. The task of the invention was also to simplify the connector manufacturing technology.
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According to the invention, the load-bearing frame of a construction connector is formed as a lightweight rectangular cuboid and includes at least one pair parallel omega type steel profiles, one above the other, with their backs oriented to each other. Spacers connecting these two omega steel profile into a load-bearing frame in the form of a rectangular cuboid are attached to the ends of this pair of omega type still profile sections, wherein the load-bearing frame is filled with thermally insulating elements.
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According to the invention, the load-bearing frame of the construction connector is characterised in that the spacers are formed as C-channel profiles with arms facing each other, wherein the ends of the omega type steel profiles are connected to the depth sections of the C-channel profiles, between the arms of these C-channel profiles.
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Two pins are preferably attached to each of the C-channel profiles, to its depth section, at the area of connection of the C-channel depth section with the omega steel profile and between the C-channel profile arms, to which the two arms of the omega steel profiles are attached while the pins protrude outside the frame, on the other side of the C-channel profiles.
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In another preferable variant of the solution according to the invention, each pin is installed inside the frame, to the arm and to the back of the omega steel profile.
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The load-bearing frame of a construction connector preferably contains thermal insulation.
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The thermal insulation of the construction connector is preferably coated with a fire protection layer.
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According to the invention, a new design of the frame of a construction connector was developed. According to the invention, the problem of increasing the thickness of thermal insulation with increasing length of the load-bearing frame was solved without a loss of resistance parameters of said frame in terms of both the bending moment and the shear force. The term length of the load-bearing frame of the connector is understood here as the length of the design of the load-bearing fame between the elements connecting the connector with the load bearing frame attached on said frame, to the terrace slab on one side and to the structure on the other. It turned out during tests that the load-bearing frame according to the invention, in its extended version adapted to the increased thickness of thermal insulation, maintained the required resistance parameters.
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Design simplicity and flexible use of the load-bearing frame of the connector was ensured. Flexibility should be understood here as freedom of the designer in terms of designing the points where pins comprising elements attaching elements of the load-bearing frame may be placed. The manufacturing technology of the load-bearing frame and of the connector as a whole was also significantly simplified.
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It was unexpectedly discovered that the aforementioned problem was solved by the use of spacers in the load-bearing frame in the form of C-channels, between the sections of the omega cross-section steel profile. This C-channel profile has been selected to cooperate with omega steel profiles. Two spacer sections in the form of C-channel profiles limit the length and height of the load-bearing frame of the connector on both sides, that is on the side of the structure ceiling and on the side of the terrace slab.
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This also allows the pins to be attached at the selected locations, on the surface of the central sections of both C-channel. For the purposes of this patent disclosure it was assumed that the C-channel has two arms and the depth section connecting said arms. Arms of the omega steel profiles are supported on said pins, on one side of the C-channel depth sections and between the arms of the C-channel profile, while to the other side of the depth section of each C-channel, for example ends of reinforcing bars intended for installation on the connector in the reinforced concrete can be attached to said pins. If used for connecting with steel structures of a building and of a terrace slab, the disclosed connecting pins may be threaded and provided with dedicated nuts. The surfaces of depth sections of C-channel used on both sides of the load-bearing frame also offer the designer freedom in selection of locations for openings used to install said pins. The load-bearing frame according to the invention became more flexible in terms of its use thanks to the proposed design.
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The use of two spacer sections of the C-channel instead of spacers provided as steel bars known in the art enabled the frame manufacturing technology to be also simplified by simplifying the positioning of these two C-channel sections instead of positioning at least four reinforcing bars in the load-bearing frame manufacturing technology known in the art.
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The object of the invention has been presented in an embodiment in the attached drawing, in which individual figures of the drawing represent as follows:
- Fig. 1a -
- a perspective view of the connector with the load-bearing frame in the first embodiment.
- Fig. 1b -
- connector with the load-bearing frame according to fig. 1 in a side view.
- Fig. 1c -
- connector with the load-bearing frame according to fig. 1a viewed towards the C-channel reinforcing bar.
- Fig. 1d -
- connector with the load-bearing frame according to fig. 1a in a top view.
- Fig. 1e -
- connector with the load-bearing frame according to fig. 1d with a thermal insulation unit in a top view.
- Fig. 1f -
- connector with the load-bearing frame according to fig. 1b with the thermal insulation unit presented clearly together with parts of the connected reinforced concrete elements.
- Fig. 2a -
- connector with the load-bearing frame for connecting a reinforced concrete element with a steel element, in a perspective view.
- Fig. 2b -
- connector with the load-bearing frame according to fig. 2a in a top view.
- Fig. 2c -
- connector with the load-bearing frame according to fig. 2a in a side view.
- Fig. 2d -
- connector with the load-bearing frame according to fig. 2a viewed from the side of its attachment to the steel element.
- Fig. 2e -
- connector with the load-bearing frame according to fig. 2a viewed from the side of its attachment to a reinforced concrete element.
- Fig. 3a -
- connector with the load-bearing frame for connecting two steel elements.
- Fig. 3b -
- connector with the load-bearing frame according to fig. 3a in a side view.
- Fig. 3c -
- connector with the load-bearing frame according to fig. 3a in a top view.
- Fig. 4 -
- cross-section through the load-bearing frame, in a plane between the C-Channel sections.
Example 1
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Fig. 1a shows the first embodiment of the construction connector with the load-bearing frame 1. The load-bearing frame 1 has the structure similar to a rectangular cuboid. The side walls of the load-bearing frame 1 are sections of a C-channel 4, 5 with arms facing each other, as shown in Fig. 1a, 1b, and Fig. 2a and 2b. The C-channel sections 4, 5 are connected via two sections 6, 7 of an omega cross-section open profile. The sections 6, 7 of an omega cross-section profile are attached to the depth sections of the C-channels 4, 5 at the end of said C-channels 4, 5, between the arms of the C-channels 4, 5. The description of the C-channel includes the term depth section for the part of the C-channel located between the arms of said C-channel. Fig. 1a and Fig. 1b, Fig. 1c and Fig. 1d do not show the insulation elements to provide a clear picture of the connector design. Fig. 1a and Fig. 1b present the design of the load-bearing frame 1 including other connector elements, in an embodiment intended for connecting two reinforced concrete construction elements. In this embodiment, the connector includes a load-bearing frame 1 and two C-shaped reinforcing bars 2,3 connected with said frame 1.
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The sections 6, 7 of the omega cross-section open profiles are attached to C-channels 4, 5 such that their backs are facing each other. Pins 8 are placed in the depth sections of the C-channels 4, 5. In the embodiment of the invention shown in Fig. 1a to Fig. 1f, the pins 8 are smooth and protrude from the depth sections of each C-channel 4, 5, on both sides of said C-channel. In this embodiment, the load-bearing frame 1 has eight pins 8, four located at each section of the C-channel 4, 5.
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The design described and presented in the figures includes a load-bearing frame 1 provided as a lightweight rectangular cuboid consisting of four main elements: two sections 4, 5 of the C-channel connected with two sections 6, 7 of the omega cross-section open profile, as described above. Each section 4, 5 of the C-channel is provided with four pins 8. The term pin should be understood in this patent disclosure as a steel pin installed in a previously prepared opening provided in the C-channel 4, 5. Fig. 1a, Fig. 1b and Fig. 1c show smooth pins 8, and in this embodiment, reinforcing bars 2, 3 formed as loops are attached to the top pairs of pins 8, on both sides of the load-bearing frame 1. Fig. 1c presents a connector in this embodiment, viewed towards the reinforcing bar 3 and a C-channel section 5. The same embodiment is shown in Fig. 1d, presenting the connector in the embodiment in a top view, wherein two reinforcing bars 2, 3 are attached to the load-bearing frame 1 on both sides. In this embodiment, the connector is used to connect two reinforced concrete elements in the form of a balcony slab 9 with a structure ceiling 10. This example application of a connector with the load-bearing frame 1 according to the invention is shown in Fig. 1f. This figure also shows thermal insulation 11 in a side view, with the load-bearing frame 1 presented inside the insulation 11. Thermal insulation 11 is an element known in the art and is a range of known profiles made of thermally insulating material, dedicated for placing inside the load-bearing frame 1 and usually having the shape of a rectangular cuboid. The top and the bottom surfaces of thermal insulation 11 are layers 12 of material with fire protecting properties. This is shown in Fig. 1f. Fig. 1e shows a connector with the load-bearing frame 1 according to Fig. 1d with thermal insulation. Fig. 1e and 1f show smooth reinforcing bars 2, 3, however, other embodiments may use ribbed reinforcing bars.
Example 2
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The subsequent Figs. 2a to Fig. 2e show a connector with the load-bearing frame 1 according to another embodiment of the invention. Fig. 2a shows this connector with a load-bearing frame 1 in a perspective view. This embodiment of the load-bearing frame 1 is intended for use in connecting, for example, a reinforced concrete balcony slab 9 with a steel reinforcement element of a structure. Four threaded pins 8.1 are installed in the load-bearing frame 1, in both sections 4, 5 of the C-channel, wherein a reinforcing bar 2 is attached to the top pair of pins 8.1, engaging in its working position with a reinforced concrete balcony slab 9, not shown in this figure. In this embodiment, four threaded pins 8.1 with nuts are also installed in the second section of the C-channel 5, engaging in their working position with a steel reinforcing element of the ceiling, not shown in this picture. The connector with the load-bearing frame 1 according to this embodiment may also be intended to connect a steel element of the balcony slab 9 with a reinforced concrete element of the structure. Fig. 2b and 2c shows the connector according to Fig. 2a in a top view and in a side view. On the other hand, Fig. 2d shows the connector viewed towards a section of the C-channel 5, from the side where the connector is attached to a steel element. The same load-bearing frame 1 is presented in Fig. 2e viewed towards the reinforcing bar 2, from the side where this connector is attached to a reinforced concrete element.
Example 3
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Another embodiment of the solution according to the invention is shown in Figs. 3a to Fig. 3c. These figures show the connector in the form of a load-bearing frame 1, Fig. 3a in a perspective view, Fig. 3b in a side view, and Fig. 3c in a top view. The load-bearing frame 1 in this embodiment is a complete connector itself. Both sections of the C-channel 4, 5 are each equipped with four threaded pins 8.1 with nuts. The load-bearing frame 1 in this embodiment is a connector intended for connecting two steel parts of connected structure elements, not shown in the figure. Such elements require a screwed connection using nuts. In this embodiment, all threaded pins 8.1 are thus threaded elements which include threaded nuts.
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Fig. 4 shows a cross-section through the load-bearing frame 1 according to the three previously described embodiments. The cross-section according to Fig. 4 runs through a plane perpendicular to sections of steel profiles 6, 7 with an omega cross-section, between the sections 4, 5 of the C-channel. This figure shows that both sections of steel profiles 6, 7 in the load bearing frames 1 are oriented to each other with their backs and their arms are supported on threaded pins 8.1. In this embodiment, each threaded pin 8.1 is attached both to the arms and to the back of the omega cross-section steel profile 6, 7.
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The load-bearing frame 1 was provided in these embodiments by connecting two steel sections 6, 7 of an omega-shaped open profile, 154 mm long, formed using 3 mm thick steel sheet. These sections of an omega cross-section steel profile 6, 7 are attached to the spacer sections of the C-channel 4, 5 with dimensions 160 x 98 x 40 mm and thickness 6 mm. In other embodiments, the use of steel elements with other dimension parameters cannot be excluded.
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All elements of the load-bearing frame 1 and the connector containing this frame 1 are made of steel, excluding the thermal insulation profiles 11, 12. The elements are connected by welding. The welds are known elements and are not shown in the attached figures to ensure clear representation of the design of the load-bearing frame 1 of the construction connector.
List of designations used in the drawings
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- 1. Load-bearing frame
- 2. Reinforcing bar
- 3. Reinforcing bar
- 4. C-channel.
- 5. C-channel.
- 6. Omega cross-section steel profile.
- 7. Omega cross-section steel profile
- 8. Smooth pin
- 8.1. Threaded pin
- 9. Balcony slab
- 10. Ceiling
- 11. Thermal insulation
- 12. Fire protection layer