A lightweight structure

Abstract

The invention relates to cold-formed steel structures, particularly roll-formed steel structures, and proposes a unique way of using roll-formed steel studs and horizontal supports with concrete slabs in a post-and- beam approach in a setting where the walls are not load-bearing as in conventional cold-formed structures.

Description

[0001] DESCRIPTION

[0002] A LIGHTWEIGHT STRUCTURE TECHNICAL FIELD

[0003] This invention relates to lightweight steel structures, particularly cold-formed steel structures.

[0004] BACKGROUND ART

[0005] Cold-formed steel structures are characterized by thin-walled sections formed at room temperature from steel sheets, strips, or plates in roll-forming or bending machines. Roll-formed steel is a subset of cold-formed steel and provides the most benefits thanks to the accuracy, speed, and cost-effectiveness of the rollforming process. Roll-formed profiles are much lighter than hot-rolled steel profiles, usually 1 to 4 mm thick, and have consistent cross-section shapes and straightness. Because of their cost efficiency, cold-formed steel is preferred over hot-rolled steel, particularly in low-cost buildings.

[0006] The walls in typical cold-formed steel structures have cold-formed steel vertical supports covered by thin panels, usually gypsum boards or fiberboards, to form the wall's surface. The vertical supports are spaced apart at a distance, usually 40-60 cm, to sufficiently support the thin vertical panels without cracking. The slabs have horizontal supports in the form of cold-formed steel beams or trusses. Unlike hot-rolled steel structures, the walls in cold-formed steel structures are load-bearing and support the slabs. Each vertical support is connected to a horizontal support, resulting in a dense arrangement of vertical and horizontal supports. Vertical diagonal braces are used between the vertical supports for the structure's lateral stability. That configuration provides efficient solutions for some instances; however, the arrangement of the horizontal supports in known cold-formed steel structures is ineffective for some slab types, such as those with topping concrete. The cold-formed steel horizontal supports require more depth than hot -rolled steel beams for the same span, so topping concrete adds further thickness to the already thicker slabs compared to most other types. The close positioning of the horizontal supports, each linked to a vertical support, also introduces complexity in manufacturing, managing, and assembling. Additionally, the contribution of each diagonal brace placed between adjacent vertical supports is slight, and the structure demands too many diagonal braces for adequate lateral stability, leading to further complexity, elevated labor costs, and inefficiency.

[0007] Therefore, our invention aims to suggest an improved lightweight structure that avoids the disadvantages of the prior art cold-formed steel structures.DISCLOSURE OF THE INVENTION

[0008] For the purposes I stated above and in accordance with the invention, I suggest a cold-formed steel structure, having at least one wall and at least one slab, the wall having a plurality of vertical studs and at least one vertical diagonal brace, the vertical studs being made of cold-formed steel, and adapted to be covered with at least one vertical panel that forms the surface of the wall, while the vertical diagonal brace, positioned between at least two vertical studs and connected to them, and the slab, having a plurality of horizontal supports, each being made of cold-formed steel, and connected at one end to one of the vertical studs, transmitting the weight of the slab and any load acting thereon to the vertical studs, the cold-formed steel structure characterized in that, the vertical studs have a first and a second type, whereby the horizontal supports and the vertical diagonal braces connect only to the vertical studs of the first type, while the vertical studs of the second type are adjusted to support the vertical panels that forms the surface of the walls. Incorporating a second type of vertical stud enables us to considerably reduce the number of supporting vertical studs, vertical diagonal braces, and connected horizontal supports. Fewer vertical diagonal braces and horizontal supports significantly lower manufacturing, managing, and assembling complexity. As the quantity of supporting elements decreases, the load on each element increases. Increasing the cross-sectional area of these elements can effectively tackle the issue of excessive stress accumulation. However, the susceptibility of cold-formed steel elements to buckling poses a more significant challenge.

[0009] In a preferred embodiment, wherein the cold-formed steel structure can rest on a foundation, and the slab can have in-plane stiffness, adapted to transmit loads to the vertical studs of the first type, the loads acting horizontally on the cold-formed steel structure in any direction, wherein the vertical studs of the first type, in combination with the vertical diagonal braces, can be adapted to receive the loads acting horizontally on the steel structure and transmit them to the foundation, such that, the cold-formed steel structure gains lateral stiffness without relying on a frame action between the vertical studs of the first type and the connected horizontal supports. This setup ensures that the horizontal supports bear only vertical loads acting perpendicularly to their longitudinal axis while the vertical studs of the first type withstand only axial loads acting along their longitudinal axis. This arrangement protects both the horizontal supports and the vertical studs from buckling.

[0010] In another preferred embodiment, at least one of the horizontal supports may be connected to one of the vertical studs of the first type through a simple connection, preventing any linear motion while allowing rotation about any axis. That adds a further measure of protection for the horizontal supports and the verticalstuds of the first type against the bending effects of the horizontal loads acting on the building, which can cause both the horizontal supports and the vertical studs to buckle.

[0011] In another preferred embodiment, at least one of the vertical diagonal braces and at least two of the adjacent vertical studs of the first type may be interconnected, creating connection points at their intersections to form triangles arranged within a vertical truss along the length of the vertical studs of the first type. Additionally, the cold-formed steel structure can have at least one elongated horizontal element positioned between the adjacent vertical studs of the first type, the adjacent vertical studs with at least one vertical diagonal brace between them, and the elongated horizontal element can be connected to them in such a way that when there are two connection points, each end is located at one of the connection points; if there is only one connection point, one end is connected to that point while the other end is connected to the corresponding vertical stud of the first type, thus creating an additional connection point. The horizontal supports aligned with the adjacent vertical studs of the first type, which have at least one cross-brace between them, are preferably connected only to the connection points on them. These arrangements ensure that the vertical studs of the first type primarily experience forces acting along their longitudinal axes, similar to those in the trusses.

[0012] In another preferred embodiment, the cold-formed steel structure can have at least one joist between a pair of horizontal supports connected to it. A plurality of joists placed along the longitudinal axis of the horizontal supports stabilize the horizontal support against lateral deformations and buckling. The slab is preferably made of cast concrete. The concrete slab may sit on top of at least one of the joists, such that an upper portion of at least one of the horizontal supports that the joist is connected to is embedded in the concrete, providing a resistance for the horizontal support against buckling and making the embedded portion of the horizontal support transmit shear forces from the slab acting horizontally on the embedded portion. It is well known that when the beams are subjected to vertical loads acting perpendicular to their longitudinal axes, their upper portion becomes prone to buckling due to the generation of excessive compression forces there. On the other hand, the horizontal support can have an upper edge, and if we adjust the upper edge of the horizontal supports to be level with the top of the slab, we can have a relatively slim slab. The slab can preferably have at least one sheet metal deck on which the concrete is placed and cast. As each vertical support is connected to a horizontal support in typical cold-formed steel systems, the distance between the horizontal supports is too narrow to accommodate joists and sheet metal deck. In conventional systems, a concrete slab may be placed on top of the horizontal supports; however, this adds unnecessary thickness to the slab, which is already thicker than most other types.In another preferred embodiment, at least one of the horizontal supports can have a plurality of shear connectors embedded in the concrete and connected to the horizontal support, restricting the movement of the horizontal support relative to the slab. The horizontal support can have a plurality of holes, and the shear connectors are preferably elongated, inserted into the holes, and retained therein. At least one of the shear connectors can have an enlarged head at the distal ends, providing anchorage for the shear connector to restrict horizontal movement of the horizontal support relative to the slab.

[0013] In a preferred embodiment, the slab can have reinforcements, the joists can be made from cold-formed steel, and the cold-formed steel structure can have at least one second elongated horizontal element lying between the vertical studs and connected thereto, in a way, stabilizing the position of the studs relative to each other. At least one of the horizontal supports and joists can be a truss. The slab may be constructed from wood or fiberboard.

[0014] BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 shows a perspective of an embodiment of the cold-formed steel structure with vertical studs of the first and second types and the slab with cast concrete.

[0016] Figure 2 shows a perspective of an embodiment of the cold-formed steel structure with vetical studs of the first type with the cross braces.

[0017] Figure 3A shows a perspective of an embodiment of the cold-formed steel structure with the upper portion of the horizontal supports embedded in concrete and the top of the slab level with the upper edge of the horizontal supports.

[0018] Figure 3B shows a perspective of an embodiment of the cold-formed steel structure with concrete above the horizontal supports and joists.

[0019] Figure 3C shows a perspective of an embodiment of the cold-formed steel structure, with the upper portion of the horizontal support embedded in concrete and the top of the slab over the level of the upper edge of the horizontal support.

[0020] Figure 4 shows a detailed perspective of an embodiment of the cold-formed steel structure with shear connectors.Figure 5 shows a perspective of an embodiment of the cold-formed steel structure with horizontal support and joists formed as trusses.

[0021] Figure 6 shows a perspective of an embodiment of the cold-formed steel structure with vertical studs of the first and second types, the slab with wooden panels, and horizontal diagonal braces.

[0022] BEST MODES FOR CARRYING OUT THE INVENTION

[0023] For the purposes I stated above and in accordance with the invention, I suggest a cold-formed steel structure 1, having at least one wall 2 and at least one slab 3, the wall 2 having a plurality of vertical studs 4 and at least one vertical diagonal brace 9, the vertical studs 4 being made of cold-formed steel, and adapted to be covered with at least one vertical panel that forms the surface of the wall 2, while the vertical diagonal brace 9, positioned between at least two vertical studs 4 and connected to them, and the slab 3, having a plurality of horizontal supports 10, each being made of cold-formed steel, and connected at one end to one of the vertical studs 4, transmitting the weight of the slab 3 and any load acting thereon to the vertical studs 4, the cold-formed steel structure 1 characterized in that, the vertical studs 4 have a first 5 and a second type 6, whereby the horizontal supports 10 and the vertical diagonal braces 9 connect only to the vertical studs of the first type 5, while the vertical studs of the second type 6 are adjusted to support the vertical panels that forms the surface of the walls 2.

[0024] Incorporating a second type 6 of vertical stud enables us to considerably reduce the number of supporting vertical studs, vertical diagonal braces 9, and connected horizontal supports 10. Fewer vertical diagonal braces 9 and horizontal supports 10 significantly lower manufacturing, managing, and assembling complexity. As the quantity of supporting elements decreases, the load on each element increases. Increasing the cross-sectional area of these elements can effectively tackle the issue of excessive stress accumulation. Various methods can be employed to achieve this, such as using thicker sheet metal to create the studs, attaching two C-studs together, or utilizing vertical studs with specialized cross-sections. However, the susceptibility of cold-formed steel elements to buckling poses a more significant challenge. It is crucial to take special measures carefully to protect them from buckling.

[0025] Figure 1 shows a perspective of an embodiment of the cold-formed steel structure 1 with vertical studs of the first 5 and second 6 types and the slab 3 with cast concrete 7. As shown in the Figure, the cold-formed steel structure 1 can rest on a foundation 11, and the slab 3 can have in-plane stiffness, adapted to transmit loads to the vertical studs of the first type 5, the loads acting horizontally on the cold -formed steel structure1 in any direction, wherein the vertical studs of the first type 5, in combination with the vertical diagonal braces 9, can be adapted to receive the loads acting horizontally on the steel structure and transmit them to the foundation 11 , such that, the cold-formed steel structure 1 gains lateral stiffness without relying on a frame action between the vertical studs of the first type 5 and the connected horizontal supports 10. This setup ensures that the horizontal supports 10 bear only vertical loads acting perpendicularly to their longitudinal axis while the vertical studs of the first type 5 withstand only axial loads acting along their longitudinal axis. This arrangement protects both the horizontal supports 10 and the vertical studs from buckling.

[0026] In another preferred embodiment, at least one of the horizontal supports 10 may be connected to one of the vertical studs of the first type 5 through a simple connection, preventing any linear motion while allowing rotation about any axis. That adds a further measure of protection for the horizontal supports 10 and the vertical studs of the first type 5 against the bending effects of the horizontal loads acting on the building, which can cause both the horizontal supports 10 and the vertical studs to buckle.

[0027] Figure 2 shows a perspective of an embodiment of the cold-formed steel structure 1 with vetical studs of the first type 5 with the vertical diagonal braces 9. As shown in Figure, at least one of the vertical diagonal braces 9 and at least two of the adjacent vertical studs of the first type 5 may be interconnected, creating connection points 15 at their intersections to form triangles arranged within a vertical truss along the length of the vertical studs of the first type 5. Additionally, the cold-formed steel structure 1 can have at least one elongated horizontal element 14 positioned between the adjacent vertical studs of the first type 5, the adjacent vertical studs with at least one vertical diagonal brace 9 between them, and the elongated horizontal element 14 can be connected to them in such a way that when there are two connection points 15, each end is located at one of the connection points 15; if there is only one connection point 15, one end is connected to that point while the other end is connected to the corresponding vertical stud of the first type 5, thus creating an additional connection point 15. The horizontal supports 10 aligned with the adjacent vertical studs of the first type 5, which have at least one vertical diagonal brace 9 between them, are preferably connected only to the connection points 15 on them. These arrangements ensure that the vertical studs of the first type 5 primarily experience forces acting along their longitudinal axes, similar to those in the trusses 28.

[0028] In another preferred embodiment, the cold -formed steel structure 1 can have at least one joist 16 between a pair of horizontal supports 10 connected to it. A plurality of joists 16 placed along the longitudinal axis of the horizontal supports 10 stabilize the horizontal support 10 against lateral deformations and buckling. Theslab 3 is preferably made of cast concrete 7. Figure 3C shows a perspective of an embodiment of the cold-formed steel structure 1, with the upper portion 20 of the horizontal support 10 embedded in concrete 7 and the top of the slab 19 over the level of the upper edge 18 of the horizontal support 10. As shown in Figure, the concrete slab 3 may sit on top of at least one of the joists 16, such that an upper portion 20 of at least one of the horizontal supports 10 that the joist 16 is connected to is embedded in the concrete 7, providing a resistance for the horizontal support 10 against buckling and making the embedded portion 21 of the horizontal support 10 transmit shear forces from the slab 3 acting horizontally on the embedded portion 21. It is well known that when the beams are subjected to vertical loads acting perpendicular to their longitudinal axes, their upper portion 20 becomes prone to buckling due to the generation of excessive compression forces there. On the other hand, as shown in Figure 3A, the horizontal support 10 can have an upper edge 18, and if we adjust the upper edge 18 of the horizontal supports 10 to be level with the top 19 of the slab 3, we can have a relatively slim slab 3. The slab 3 can preferably have at least one sheet metal deck 22 on which the concrete is placed and cast. Figure 3B shows a perspective of a practical alternative embodiment of the cold-formed steel structure 1 with cast concrete 7 above the horizontal support 10 and joists 16. While giving away the benefits of embedding the upper portion 20 of the horizontal supports 10, that embodiment provides the reinforcement 26 and the sheet metal deck 22 to be used without cutting and trimming. As each vertical support is connected to a horizontal support 10 in typical cold-formed steel systems, the distance between the horizontal supports 10 is too narrow to accommodate joists 16 and sheet metal deck 22. In conventional systems, a concrete slab 7 may be placed on top of the horizontal supports 10; however, this adds unnecessary thickness to the slab, which is already thicker than most other types.

[0029] As shown in Figure 4, in another preferred embodiment, at least one of the horizontal supports 10 can have a plurality of shear connectors 23 embedded in the concrete and connected to the horizontal support 10, restricting the movement of the horizontal support 10 relative to the slab 3. The horizontal support 10 can have a plurality of holes 24, and the shear connectors 23 are preferably elongated, inserted into the holes 24, and retained therein. At least one of the shear connectors 23 can have an enlarged head 25 at the distal ends, providing anchorage for the shear connector 23 to restrict horizontal movement of the horizontal support 10 relative to the slab 3. As shown in Figure 4, the enlarged heads 25 can be made from nuts fixed at the distal ends of the shear connectors 23.

[0030] In a preferred embodiment, the slab 3 can have reinforcements 26, the joists 16 can be made from cold-formed steel, and the cold-formed steel structure 1 can have at least one second elongated horizontal element 27 lying between the vertical studs 4 and connected thereto, in a way, stabilizing the position of the studs 4 relative to each other. At least one of the horizontal supports 10 and joists 16 can be a truss 28, as shown inFigure 5. Figure 6 shows a perspective of an embodiment of the cold-formed steel structure 1 with vertical studs of the first 5 and second types 6, the slab 3 with wooden panels, and horizontal diagonal braces 30. The slab 3 may be constructed from wood or fiberboard 29. In this configuration, lateral loads acting on the cold-formed steel structure 1 are transmitted to the vertical studs of the first type 5 through horizontal supports 10, horizontal diagonal braces 30, and joists 16 , in combination.

[0031] INDUSTRIAL APPLICABILITY

[0032] All of the elements forming the lightweight structure explained in the document can be produced with known standard methods and technologies. Vertical studs, horizontal supports, joists, and elongated horizontal elements can be manufactured using roll-form machines from structural-grade steel sheets. Any element with a cross-section that is not economical to produce by roll-forming can be produced using alternative cold-forming methods, like CNC laser cutting and bending.

Claims

CLAIMS1.1 claim a cold-formed steel structure, comprising at least one wall and at least one slab, the wall comprising a plurality of vertical studs and at least one vertical diagonal brace, the vertical studs being made of cold-formed steel, and adapted to be covered with at least one vertical panel that forms the surface of the wall, while the vertical diagonal brace, positioned between at least two vertical studs and connected thereto, and the slab, comprising a plurality of horizontal supports, each being made of cold-formed steel, and connected at one end to one of the vertical studs, transmitting the weight of the slab and any load acting thereon to the vertical studs, the cold-formed steel structure characterized in that, the vertical studs comprise a first and a second type, whereby the horizontal supports and the vertical diagonal braces connect only to the vertical studs of the first type, while the vertical studs of the second type are adjusted to support the vertical panels that forms the surface of the walls.

2. A cold-formed steel structure in accordance with the claim 1, wherein the cold-formed steel structure rests on a foundation, and the slab has in-plane stiffness, adapted to transmit loads to the vertical studs of the first type, the loads acting horizontally on the cold-formed steel structure in any direction, wherein, the vertical studs of the first type, in combination with the vertical diagonal braces, are adapted to receive the loads acting horizontally on the steel structure and transmit them to the foundation.

3. A cold-formed steel structure in accordance with claims 1 and 2, wherein at least one of the horizontal supports is connected to one of the vertical studs of the first type through a simple connection, the connection preventing any linear motion while allowing rotation about any axis.

4. A cold-formed steel structure in accordance with claims 1-3, wherein at least one of the vertical diagonal braces and at least two of the adjacent vertical studs of the first type are interconnected, creating connection points at their intersections to form triangles arranged within a vertical truss along the length of the vertical studs of the first type.

5. A cold-formed steel structure in accordance with the claim 4, wherein the cold-formed steel structure further comprises at least one elongated horizontal element positioned between the adjacent vertical studs of the first type, the adjacent vertical studs with at least one vertical diagonal brace between them, and the elongated horizontal element is connected thereto in such a way that when there are two connection points, each end is located at one of the connection points and if there is only one connection point, one end is connected to that point while the other end is connected to the corresponding vertical stud of the first type, thus creating an additional connection point.

6. A cold-formed steel structure in accordance with the claim 5, wherein the horizontal supports aligned with the adjacent vertical studs of the first type, the adjacent vertical studs with at least one cross-brace between them, are connected only to the connection points on them.

7. A cold-formed steel structure in accordance with the preceding claims, wherein the cold-formed steel structure further comprises at least one joist between a pair of horizontal supports and connected thereto.

8. A cold-formed steel structure in accordance with the preceding claims, wherein the slab is made of cast concrete.

9. A cold-formed steel structure in accordance with claim 8, wherein the concrete slab sits on top of at least one of the joists, such that an upper portion of at least one of the horizontal supports that the joist is connected to is embedded in the concrete, providing a resistance for the horizontal support against buckling and making the embedded portion of the horizontal support transmit shear forces from the slab acting horizontally on the embedded portion.

10. A cold-formed steel structure in accordance with claim 9, wherein the horizontal support has an upper edge, and the upper edge is level with the top of the slab.

11. A cold-formed steel structure in accordance with claims 8-10, wherein the slab comprises at least one sheet metal deck on which the concrete is placed and cast.

12. A cold-formed steel structure in accordance with claims 9-11, wherein at least one of the horizontal supports comprises a plurality of shear connectors embedded in the concrete and connected to the horizontal support, the shear connectors restricting movement of the horizontal support relative to the slab.

13. A cold-formed steel structure in accordance with claim 12, wherein the horizontal support comprises a plurality of holes, and the shear connectors are elongated, inserted into the holes, and retained therein.

14. A cold-formed steel structure in accordance with claims 12 and 13, wherein at least one of the shear connectors comprises an enlarged head at the distal ends, providing anchorage for the shear connector to restrict horizontal movement of the horizontal support relative to the slab.

15. A cold-formed steel structure in accordance with any of the preceding claims, wherein the slab comprises reinforcements therein.

16. A cold-formed steel structure in accordance with any of the preceding claims, wherein the joists are made from cold-formed steel.

17. A cold-formed steel structure in accordance with any of the preceding claims, wherein the wall comprises at least one second elongated horizontal element lying between the vertical studs and connected thereto, in a way, stabilizing the position of the studs relative to each other.

18. A cold-formed steel structure in accordance with any of the preceding claims, wherein at least one of the horizontal supports is in the form of a truss.

19. A cold-formed steel structure in accordance with any of the preceding claims, wherein at least one of the joists is a truss.

20. A cold-formed steel structure in accordance with claims 1 and 3-7, and 15-18, wherein the slab is made from wood.

21. A cold-formed steel structure in accordance with claims 1 and 3-7, and 15-18, wherein the slab is made from fiberboard.

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