A reinforced concrete column with a thin-walled steel tube

Abstract

This utility model discloses a reinforced thin-walled steel tube concrete column, comprising a thin-walled steel tube column, with at least one stiffening member provided inside the thin-walled steel tube column. The length direction of the stiffening member is consistent with the length direction of the thin-walled steel tube column, and one end of the stiffening member extends from one end of the thin-walled steel tube column to the other end of the thin-walled steel tube column. The opposite sides of the stiffening member are respectively fixedly connected to the two adjacent inner sidewalls of the thin-walled steel tube column. Concrete is poured inside the thin-walled steel tube column to form the reinforced thin-walled steel tube concrete column.

Description

Technical Field

[0001] This utility model relates to the field of building structure technology, specifically to a reinforced thin-walled steel tube concrete column. Background Technology

[0002] Concrete-filled steel tube columns are constructed by pouring concrete inside steel tubes. This not only overcomes the shortcomings of both materials but also fully leverages their advantages, resulting in high load-bearing capacity, good seismic performance, and convenient construction. To reduce the thickness of the steel tubes in ordinary concrete-filled steel tube columns and improve the economics of square steel tube columns, thin-walled square steel tube columns have emerged. However, thin-walled concrete-filled steel tube columns exhibit prominent local stability issues, leading to a weaker constraint effect of the thin-walled steel tube on the core concrete. This results in poor interaction between the two materials, preventing the full utilization of their respective material advantages and consequently causing low load-bearing capacity and poor ductility. Common stiffening measures for thin-walled steel tube columns include welding studs, longitudinal stiffening ribs, and restraint rods to the inner wall of the steel tube. Figure 6 As shown in Figure ac, these stiffening measures can enhance the interaction between thin-walled steel pipe columns and concrete. However, in actual construction, it was found that these commonly used stiffening measures in existing technologies are very disadvantageous for thin-walled steel pipe columns. This is because, as... Figure 6 As shown in Figure a, welded studs are very prone to piercing through thin-walled steel pipe columns, and the stiffening effect is poor after actual construction and use. For example... Figure 6 As shown in Figure b, longitudinal stiffening ribs can be installed inside the steel pipe column. However, these longitudinal stiffening ribs require sufficient rigidity to meet the stiffening requirements. Therefore, they need to extend a sufficient length into the steel pipe column to function. However, in actual construction, it has been found that when steel pipe columns are spliced ​​on-site, the longitudinal stiffening ribs inside the two spliced ​​steel pipe columns cannot be welded. This results in discontinuous longitudinal force transmission, interrupting the force transmission and causing material waste. Figure 6 As shown in Figure c, constraint rods can also be installed inside the steel pipe column. Although the constraint effect is good, holes need to be pre-drilled at the corresponding positions in the steel pipe during production. This is not only troublesome to manufacture, but also weakens the thin-walled steel pipe column. In addition, the nuts of the constraint rods protrude from the steel pipe, which increases additional decoration costs and adversely affects the stiffening effect. Further improvements are still needed. Utility Model Content

[0003] To address the aforementioned shortcomings of existing technologies, the purpose of this utility model is to provide a reinforced thin-walled steel tube concrete column, which solves the problems that existing reinforcement measures have adverse effects on thin-walled steel tube columns and are not suitable for them. Furthermore, thin-walled steel tube columns suffer from poor restraint effect, low bearing capacity, and poor ductility during actual construction.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A reinforced thin-walled steel tube concrete column includes a thin-walled steel tube column, with at least one stiffener inside the thin-walled steel tube column. The length direction of the stiffener is consistent with the length direction of the thin-walled steel tube column, and one end of the stiffener extends from one end of the thin-walled steel tube column to the other end of the thin-walled steel tube column. The stiffener is fixedly connected to two adjacent inner sidewalls of the thin-walled steel tube column on opposite sides along its length direction. Concrete is poured inside the thin-walled steel tube column to form the reinforced thin-walled steel tube concrete column.

[0006] Preferably, the thin-walled steel pipe column is composed of two U-shaped steels, each of which has an open end and a closed end; the open ends of the two U-shaped steels are arranged opposite each other to form a thin-walled steel pipe column, and the open ends of the two U-shaped steels are fixedly connected.

[0007] Preferably, the stiffener is a corrugated steel bar with crests and troughs, and the crests and troughs of the corrugated steel bar are fixedly connected to the two adjacent inner sidewalls of the thin-walled steel pipe column, respectively.

[0008] Preferably, the width of both the crests and troughs is greater than the distance between two adjacent crests or two adjacent troughs.

[0009] Preferably, the crests and troughs are both bent toward the direction away from the inner wall of the thin-walled steel pipe column and continue to extend to form a connecting end. The corrugated steel bars are fixedly connected to the two adjacent inner walls of the thin-walled steel pipe column through the connecting ends.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] 1. This utility model designs a stiffener with a special structure and shape for thin-walled steel tube concrete columns. The stiffener provides continuous constraint on the outer surface of the steel tube of the thin-walled steel tube column, effectively controlling the buckling mode of the steel tube and reducing the range of buckling of the steel tube. This allows the thin-walled steel tube column to be well applied in actual construction and improves the constraint effect of the thin-walled steel tube column on the concrete.

[0012] 2. This utility model designs two different stiffening components: corrugated steel bars of different forms. One type features corrugated steel bars where the width of the crests is greater than the distance between adjacent crests. Compared to serrated steel bars, this form results in a denser distribution of crests and troughs, allowing the steel bars to provide continuous constraint on the steel pipe. This continuous constraint further restricts the buckling of the thin-walled steel pipe column, allowing it to fully utilize its strength with less steel reinforcement. Furthermore, it is inclined and intersected with the thin-walled steel pipe column and concrete, acting as a better shear connector and enhancing the interaction between the thin-walled steel pipe column and concrete. The other type features corrugated steel bars with bidirectional bending at both ends to form connecting ends. The simultaneous bending of crests and troughs at the connecting ends allows for a sufficiently straight section for welding between the steel bar and the steel pipe, resulting in a more favorable weld stress distribution. This avoids the weak weld areas found between serrated steel bars and the steel pipe, ensuring more reliable force transmission and a higher weld bearing capacity. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of one embodiment of the stiffening member in this utility model after being connected to a thin-walled steel pipe column.

[0014] Figure 2 This is a schematic diagram of the thin-walled steel pipe column obtained after assembling the U-shaped steel in this utility model.

[0015] Figure 3 This is a schematic diagram of one embodiment of the stiffening component in this utility model.

[0016] Figure 4 This is a schematic diagram of another embodiment of the stiffening member in this utility model after it is connected to a thin-walled steel pipe column.

[0017] Figure 5 This is a schematic diagram of another embodiment of the stiffening member in this utility model.

[0018] Figure 6 This is a schematic diagram of the structure of a conventional steel pipe column after stiffening treatment; a is stud stiffening, b is longitudinal stiffening rib, and c is restraint rod.

[0019] Figure 7 This is a schematic diagram of the structure after connecting serrated steel bars to a thin-walled steel pipe column.

[0020] In the diagram: stiffener 1, U-shaped steel 2, crest 3, trough 4, connecting end 5, vertical section 6. Detailed Implementation

[0021] This utility model will be clearly and completely described with reference to the accompanying drawings of the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on this utility model are within the protection scope of this utility model.

[0022] This utility model provides a reinforced thin-walled steel tube concrete column, such as... Figure 1-5 As shown, the structure includes a thin-walled steel pipe column, with at least one stiffener 1 inside the thin-walled steel pipe column. The length direction of the stiffener is consistent with the length direction of the thin-walled steel pipe column, and one end of the stiffener extends from one end of the thin-walled steel pipe column to the other end. The opposite sides of the stiffener are fixedly connected to the two adjacent inner sidewalls of the thin-walled steel pipe column, respectively. Concrete is poured inside the thin-walled steel pipe column to form the reinforced thin-walled steel pipe concrete column.

[0023] Thin-walled steel pipes are not simply judged by their thickness. In existing technology, the "Code for Design of Composite Structures" stipulates that the cross-sectional dimensions of ordinary rectangular or square steel-concrete composite columns should not be less than 400mm, the steel pipe thickness should not be less than 8mm, and the ratio of the steel pipe width to its thickness should not exceed the limit of 60 × (235 / f ak ) 0.5 ,in f akThis refers to the standard value of the tensile strength of the steel pipe. In this invention, the thin-walled steel-concrete composite column refers to a steel-concrete composite column where the ratio of the width to the thickness of the steel pipe exceeds this limit. Therefore, the thin-walled steel pipe in the thin-walled steel-concrete composite column of this invention falls into two categories: one where the steel pipe thickness is 2-8 mm, preferably 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, or 8 mm, corresponding to a cross-sectional width of 300-1100 mm; this can be considered a thin-walled steel pipe. The other category is where the column's cross-sectional width exceeds 1100 mm, and the steel pipe thickness cannot be simply used to determine if it is a thin-walled steel pipe. Because in this cross-sectional case, the steel pipe thickness in existing steel-concrete composite columns needs to reach at least 22 mm to meet the width-to-thickness ratio requirement. However, the steel pipe used in the thin-walled steel-concrete composite column of this invention only needs to reach 8 mm to meet the same width-to-thickness ratio requirement as existing technologies. Therefore, compared to the steel pipe thickness in existing technologies, the steel pipe used in this invention can still be considered a thin-walled steel pipe. This type of steel pipe column meets national standards while saving steel consumption, thus further improving economic efficiency and showing great application prospects. However, in actual construction, when stiffening is required for this thin-walled steel pipe column, existing stiffening methods have adverse effects on it and are not suitable for thin-walled steel pipe columns, affecting their performance in practical applications. Therefore, the applicant has proposed a stiffening measure involving the installation of serrated reinforcing bars within the thin-walled steel pipe column, such as... Figure 7As shown, this stiffening measure effectively addresses a series of adverse technical problems associated with existing stiffening techniques for thin-walled steel tube columns, demonstrating excellent restraint. However, further research revealed that the serrated reinforcing bars, fixed to the inner wall of the thin-walled steel tube column via welding, and further fixed by vertical segment 6, exhibit stress concentration under load, hindering load-bearing capacity. Moreover, this weld is a weak point, prone to tearing under reciprocating loads, leading to brittle failure that precedes buckling of the thin-walled steel tube. For engineers, this is a highly undesirable failure mode, as brittle failure often occurs suddenly and without warning. As a critical connection point, the sudden failure of the weld results in the complete loss of its stiffening function, potentially triggering large-area buckling of the steel tube or overall instability of the steel-concrete composite column. This leads to global and catastrophic damage, difficult to mitigate through deformation or early warning measures, and often resulting in serious safety accidents. Therefore, this is an undesirable and undesirable failure mode. Based on this, this utility model further improves the shape of the stiffener, hoping to transform this brittle failure into a ductile failure mode. Because when a building structure is under reciprocating loads, the ductile failure mode can fully utilize the most important mechanical advantage of steel, namely: steel uses its plastic properties to yield, and then absorbs the energy applied to the building structure by generating plastic deformation, providing valuable time for personnel evacuation and emergency measures.

[0024] In some embodiments of this utility model, such as Figure 2 As shown, the thin-walled steel pipe column is composed of two U-shaped steel bars 2, each U-shaped steel bar having an open end and a closed end; the open ends of the two U-shaped steel bars are arranged opposite each other to form a thin-walled steel pipe column, and the open ends of the two U-shaped steel bars are fixedly connected. The thin-walled steel pipe column is assembled and welded from two U-shaped steel bars. Before assembly, stiffening members are welded inside the U-shaped steel bars, which facilitates the welding operation and ensures the welding quality.

[0025] In some embodiments of this utility model, the stiffening member is a corrugated steel bar, which has crests and troughs. The crests and troughs of the corrugated steel bar are respectively fixedly connected to the two adjacent inner sidewalls of the thin-walled steel pipe column. The stiffening member can be implemented in two ways, such as... Figure 1 and Figure 3As shown, in this embodiment, the width of both the crests and troughs of the corrugated steel bar is greater than the distance between two adjacent crests or troughs. During welding, the corrugated steel bar is welded and fixed to the inner walls of the adjacent sides of the thin-walled steel pipe column through the crests and troughs, forming a 45° angle between the plane of the stiffener and the inner walls of the adjacent sides of the thin-walled steel pipe column. This not only makes the crests and troughs more densely distributed but also increases the welding length between the stiffener and the thin-walled steel pipe column, providing better continuous restraint for the thin-walled steel pipe column. Furthermore, the stiffener, the thin-walled steel pipe column, and the concrete intersect at an angle, acting as a better shear connection and further enhancing the interaction between the thin-walled steel pipe column and the concrete. Another embodiment is as follows... Figure 4 and 5 As shown, in this embodiment, both the crests and troughs bend simultaneously in a direction away from the inner wall of the thin-walled steel pipe column and continue to extend to form the connecting end 5, creating a 45° angle between the connecting end and the plane containing the corrugated steel reinforcement. Taking the plane containing the corrugated steel reinforcement as a reference, all connecting ends are located on the same side of this plane, such as... Figure 4 As shown, the corrugated reinforcing bars are fixedly connected to the two adjacent inner walls of the thin-walled steel pipe column via connecting ends. In this embodiment, the connecting ends allow for a sufficiently straight section between the corrugated reinforcing bars and the thin-walled steel pipe column for welding, resulting in more favorable stress distribution in the weld. This avoids weak areas in the weld between the serrated reinforcing bars and the steel pipe, making force transmission more reliable and ensuring the weld's load-bearing capacity. More importantly, experiments revealed that under reciprocating loads, the thin-walled steel-tube concrete columns in both implementations exhibited a yielding followed by buckling of the steel tubes. The welds between the reinforcing bars and the steel tubes possessed sufficient bearing capacity and remained intact. Ultimately, the reinforcing bars were either tensile-yielded or fractured. This process involved steel tube yielding (plastic deformation) → steel tube buckling (progressive deformation) → reinforcing bar yielding / fracture (significant plastic deformation). The entire process generated a large amount of irreversible plastic deformation and absorbed enormous energy (especially seismic input energy), which is crucial for the seismic performance of the structure. Furthermore, this process, from its inception, served as a significant visual and measurement warning signal, providing valuable time for evacuation and emergency response. It allowed the steel (steel tubes and reinforcing bars) to fully utilize its plastic properties (yielding and plastic deformation), which is one of the most important mechanical advantages of steel. Therefore, this utility model can effectively solve the problem that the weld seam is prone to tearing under reciprocating load when the serrated steel bar is fixed to the inner wall of the thin-walled steel pipe column, thus causing brittle failure. It enables the thin-walled steel pipe concrete column to achieve the ideal ductile failure mode even when subjected to reciprocating load, which not only gives full play to the important plastic properties of steel, but also improves the safety of the thin-walled steel pipe column.

[0026] In actual construction, the U-shaped steel in the thin-walled steel tube column is cold-bent into shape, and then continuous stiffeners are welded inside the U-shaped steel. These continuous stiffeners provide continuous restraint to the steel tube, delaying local buckling of the thin-walled steel tube and enhancing the restraint effect of the steel tube on the concrete. The interaction between the steel tube and the concrete is strengthened, resulting in improved concrete strength and ductility, and thus enhanced seismic performance of the component. Then, two U-shaped steels are assembled and welded together, and finally, concrete is poured into them to form a reinforced thin-walled steel tube concrete column.

[0027] This utility model is not limited to the above-described embodiments. Any structure that is the same as or similar to the above-described embodiments of this utility model is within the protection scope of this utility model.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of this utility model that do not depart from the spirit and scope of this technical solution should be covered within the scope of the claims of this utility model.

Claims

1. A reinforced thin-walled steel tube concrete column, characterized in that, The system includes a thin-walled steel pipe column, with at least one stiffener (1) inside the thin-walled steel pipe column. The length direction of the stiffener is consistent with the length direction of the thin-walled steel pipe column, and one end of the stiffener extends from one end of the thin-walled steel pipe column to the other end of the thin-walled steel pipe column. The stiffener is fixedly connected to the two adjacent inner walls of the thin-walled steel pipe column on opposite sides along its length direction. Concrete is poured inside the thin-walled steel pipe column to form the reinforced thin-walled steel pipe concrete column.

2. The reinforced thin-walled steel tube concrete column according to claim 1, characterized in that, The thin-walled steel pipe column is composed of two U-shaped steels (2), each of which has an open end and a closed end; the open ends of the two U-shaped steels are arranged opposite each other to form a thin-walled steel pipe column, and the open ends of the two U-shaped steels are fixedly connected.

3. The reinforced thin-walled steel tube concrete column according to claim 2, characterized in that, The stiffener is a corrugated steel bar with crests (3) and troughs (4). The crests and troughs of the corrugated steel bar are fixedly connected to the two adjacent inner walls of the thin-walled steel pipe column, respectively.

4. The reinforced thin-walled steel tube concrete column according to claim 3, characterized in that, The width of both the crests and troughs is greater than the distance between two adjacent crests or two adjacent troughs.

5. The reinforced thin-walled steel tube concrete column according to claim 3, characterized in that, Both the crests and troughs bend simultaneously toward the direction away from the inner wall of the thin-walled steel pipe column and continue to extend to form a connecting end (5). The corrugated steel bars are fixedly connected to the two adjacent inner walls of the thin-walled steel pipe column through the connecting end.

Images