Restrained steel bar-concrete composite beam structure

Abstract

The invention discloses a restrained steel bar-concrete composite beam structure which comprises an upper wing plate and a lower wing plate which are oppositely arranged in parallel, a plurality of webs are arranged between the upper wing plate and the lower wing plate at intervals, and the webs are perpendicular to the upper wing plate and the lower wing plate, so that the upper wing plate, the lower wing plate and the webs are integrally in an H shape; restraining steel bars are arranged in the areas corresponding to the intervals between the upper wing plate and the lower wing plate and between the adjacent web plates, the restraining steel bars are fixedly connected with the upper wing plate and the lower wing plate respectively, and a concrete structure layer covering the restraining steel bars and part or all of the web plates is poured between the upper wing plate and the lower wing plate. The steel plate is simple in structure, small in thickness, easy to machine and better in economical efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of building structures, and in particular to a constrained steel bar-concrete composite beam structure. Background Art

[0002] Common composite beams include H-steel-concrete composite beams and partially clad steel-concrete composite beams. H-steel-concrete composite beams consist of hot-rolled or welded H-steel beams connected to the concrete floor slab and the upper flange of the steel beam via shear connectors, forming a shared load-bearing member with high load-bearing capacity. However, to ensure the stability of the H-steel, the H-steel plate is typically thick, making it less economical. Furthermore, the exposed steel has poor corrosion and fire resistance, resulting in high maintenance costs. Partially clad steel-concrete composite beams are an improvement on the H-steel-concrete composite beam. Stirrups or studs are welded to the H-steel web, and then concrete is poured to fill both sides of the H-steel, flush with the flange, forming a shared load-bearing member. Compared to H-steel-concrete composite beams, they offer superior corrosion and fire resistance, and possess enhanced load-bearing capacity, stiffness, buckling resistance, and torsional resistance. However, currently, PEC beams primarily use hot-rolled or welded H-steel, resulting in thicker flanges and webs, making them less economical. In addition, the steel web divides the concrete into two independent parts, and the integrity is weak. In order to achieve a good combination effect, a large number of stirrups and studs need to be welded. The structure is complex and the production convenience needs to be further improved. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a constrained steel bar-concrete composite beam structure, which solves the problems of the existing composite beams having thick steel plates, poor economy and complex structure.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A restrained steel bar-concrete composite beam structure includes an upper wing plate and a lower wing plate arranged opposite and parallel to each other, with a plurality of web plates interspersed between the upper and lower wing plates, the web plates being perpendicular to the upper and lower wing plates, so that the upper, lower and web plates form an H-shape as a whole; restrained steel bars are disposed between the upper and lower wing plates in an area corresponding to the intervals between adjacent web plates, the restrained steel bars being fixedly connected to the upper and lower wing plates, respectively; and a concrete structural layer is cast between the upper and lower wing plates, covering the restrained steel bars and part or all of the web plates;

[0006] Among them, the restraining steel bars include two steel meshes arranged on both sides of the web, the steel meshes include multiple stacked corrugated steel bars, the corrugated steel bars include crest sections, diagonal bracing sections and trough sections, the crest sections and trough sections of the multiple corrugated steel bars are staggered, and the crest sections of the corrugated steel bars are connected to the upper wing plate, and the trough sections are connected to the lower wing plate, and the crest sections of the corrugated steel bars are inclined to one side of the width direction of the composite beam, and the trough sections are inclined to the other side of the width direction of the composite beam, so that there is an angle between the crest sections and trough sections of the corrugated steel bars and the length direction of the composite beam.

[0007] As an optimization, the angle θ between the diagonal bracing section and the length direction of the composite beam is 45°.

[0008] As an optimization, the connection area between the crest section of the corrugated steel bar and the upper wing plate or the connection area between the trough section and the lower wing plate forms a steel reinforcement section, and the area between adjacent steel reinforcement sections forms a non-reinforced section. The ratio of the length of the non-reinforced section to the thickness of the upper wing plate and the lower wing plate should meet Where L2 is the length of the non-stiffened section, t is the thickness of the upper and lower wing panels, and f y is the yield strength of the flange plate.

[0009] As an optimization, the distance between the two peaks of the corrugated steel bar is the wave width. When the height of the composite beam H≤500mm, the wave width range includes two peak segments, and satisfies 2h+L1=2L1+3L2, and L1≥L2. When the height of the composite beam 500mm<H≤700mm, the wave width range includes three peak segments, and satisfies 2h+L1=3L1+4L2, and L1≥L2. When the height of the composite beam H>700mm, the wave width range includes four peak segments, and satisfies 2h+L1=4L1+5L2, and L1≥L2, wherein L1 is the length of the steel bar reinforcement section, and h is the net distance between the upper wing plate and the lower wing plate.

[0010] As an optimization, shear connection holes are opened on the web, and the shear connection holes are covered by the concrete structure layer.

[0011] As an optimization, bolt holes are opened on the webs near the two ends of the upper wing plate and the lower wing plate, the bolt holes are located on the side where the two webs are separated, the shear connection holes are located on the side where the two webs are close to each other, and the two side end faces of the concrete structure layer are respectively located between the bolt holes and the shear connection holes of the two webs.

[0012] Compared with the prior art, this application has the following beneficial effects:

[0013] The present invention,

[0014] An H-shaped steel skeleton is formed by welding restraining steel bars and steel plates between two parallel steel plates, and then a common load-bearing member is formed by pouring concrete. The restraining steel bars replace part of the web of the traditional H-shaped steel to reduce the thickness of the upper and lower flanges of the H-shaped steel beam. The member can be designed according to the steel content ratio of ordinary reinforced concrete members, thereby achieving the purpose of fully saving materials. The structure is simple, easy to process, and more economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the H-shaped steel beam structure of the present invention;

[0016] Figure 2 This is a schematic diagram of the structure after the restraining steel bars are set in the present invention;

[0017] Figure 3 This is a schematic diagram of the structure after pouring the concrete structure layer of the present invention;

[0018] Figure 4 This is a schematic diagram of the arrangement of the restrained reinforcement bars in the present invention;

[0019] In the figure, 1 is the upper wing plate, 2 is the lower wing plate, 3 is the web plate, 4 is the corrugated steel bar, 41 is the crest section, 42 is the diagonal bracing section, 43 is the trough section, 5 is the concrete structure layer, 6 is the shear connection hole, and 7 is the bolt hole. DETAILED DESCRIPTION

[0020] The present invention will be described in further detail below with reference to the accompanying drawings.

[0021] Specific implementation: see Figure 1-Figure 4 ,

[0022] In one embodiment, a restrained steel bar-concrete composite beam structure includes an upper wing plate 1 and a lower wing plate 2 that are arranged relative to and in parallel, with a plurality of webs 3 spaced apart between the upper wing plate 1 and the lower wing plate 2. The webs 3 are perpendicular to the upper wing plate 1 and the lower wing plate 2, so that the upper wing plate 1, the lower wing plate 2, and the webs 3 are H-shaped as a whole. Specifically, in this embodiment, there are two webs 3, which are located at both ends of the composite beam. The interval between the two webs 3 forms a hole. Between the upper wing plate 1 and the lower wing plate 2, restrained steel bars are provided in the area corresponding to the interval between adjacent webs 3 (i.e., the hole). The restrained steel bars are fixedly connected to the upper wing plate 1 and the lower wing plate 2, respectively, and a concrete structural layer 5 covering the restrained steel bars and part or all of the webs 3 is cast between the upper wing plate 1 and the lower wing plate 2.

[0023] Specifically, the restraining steel bars include two steel meshes arranged on both sides of the web 3, and the steel meshes include multiple corrugated steel bars 4 stacked in layers. The wavy restraining steel bars have the following functions: ① They restrain the upper and lower wing plates 2, and can still ensure their stability when thinner steel plates are used for the flange plates, thereby reducing the thickness of the steel plates and improving economy; ② The wavy restraining steel bars connect the upper and lower flange plates with the concrete into a whole, play the role of shear connectors, and enhance the combined effect of steel and concrete; ③ The wavy restraining steel bars are like stirrups or bent steel bars in reinforced concrete beams, and directly participate in the shear resistance of the section.

[0024] Furthermore, based on the steel bar structure, it is still necessary to clarify the specific setting method of the corrugated steel bars, such as how much the bending angle of the steel bars is appropriate, and how many rows of corrugated constraint steel bars are arranged on one side. It was found through layout that after controlling the fixed bending angle, when the beam height is higher, the more layers of flat corrugated steel bars need to be set, resulting in a large width occupied by the steel bars, so that the steel bars are not constrained to the flange plate in a collinear manner. In order to further solve the above technical problems, in this embodiment, the corrugated steel bar 4 includes a peak section 41, a diagonal bracing section 42 and a trough section 43, and the peak sections 41 and trough sections 43 of the corrugated steel bars 4 are staggered, and the peak section 41 of the corrugated steel bar 4 is connected to the upper wing plate 1, and the trough section 43 is connected to the lower wing plate 2, and the peak section 41 of the corrugated steel bar 4 is inclined to one side of the width direction of the composite beam, and the trough section 43 is inclined to the other side of the width direction of the composite beam, so that the peak section 41 and the trough section 43 of the corrugated steel bar 4 have an angle with the length direction of the composite beam.

[0025] Specifically, the angle θ between the diagonal bracing section 42 and the longitudinal direction of the composite beam is 45°. The connection area between the peak section 41 of the corrugated steel bar 4 and the upper wing plate 1 or the connection area between the trough section 43 and the lower wing plate 2 forms a steel reinforcement section, and the area between adjacent steel reinforcement sections forms a non-reinforced section. The ratio of the length of the non-reinforced section to the thickness of the upper wing plate 1 and the lower wing plate 2 should meet Where L2 is the length of the non-stiffened section, t is the thickness of the upper wing plate 1 and the lower wing plate 2, and f y is the yield strength of the flange plate.

[0026] The distance between two wave crests of the corrugated steel bar 4 is the wave width. For different beam heights, different numbers of wave crests need to be embedded in one wave width to meet the force requirements.

[0027] Specifically, when two wave crests need to be embedded within a wave width L (applicable for beam heights H ≤ 500mm), the restraining reinforcement should satisfy the geometric relationship: 2h + L1 = 2L1 + 3L2. If L1 and L2 are equal, L1 = L2 = 1 / 2h; if L1 and L2 are unequal, L1 = 2h - 3L2. In this case, the critical buckling stress of the steel plate in the L1 stiffening section and the unstiffened L2 section should be close, that is, L1 should be greater than L2.

[0028] When three wave crests are embedded within a wave (applicable when beam height 500mm < H ≤ 700mm), the geometric relationship yields 2h + L1 = 3L1 + 4L2. If L1 and L2 are equal, L1 = L2 = 1 / 3h; if L1 and L2 are unequal, L1 = h - 2L2. In this case, the critical buckling stress of the L1 stiffening section and the L2 unstiffening section should be close, meaning L1 is greater than L2.

[0029] When a wave contains four wave crests (applicable for beam heights H > 700mm), the geometric relationship yields 2h + L1 = 4L1 + 5L2. If L1 and L2 are equal, L1 = L2 = 1 / 4h. If L1 and L2 are unequal, L1 = (2h - 5L2) / 3. In this case, the critical buckling stresses of the L1 stiffened section and the L2 unstiffened section should be close, meaning L1 is greater than L2.

[0030] Wherein, L1 is the length of the steel reinforcement section, and h is the clear distance between the upper wing plate 1 and the lower wing plate 2.

[0031] The crest section 41 and the trough section 43 of the corrugated steel bar 4 are both inclined, and the inclination angle is arctan(d / L1), where d is the steel bar avoidance distance. By adjusting the size of d, the problem of a large number of steel bar layers occupying a large width can be solved.

[0032] The present invention forms an H-shaped steel skeleton by welding restraining steel bars and steel plates between two parallel steel plates, and then pours concrete to form a common load-bearing member. The restraining steel bars replace part of the web 3 of the traditional H-shaped steel to reduce the thickness of the upper and lower flanges 2 of the H-shaped steel beam. The member can be designed according to the steel content ratio of ordinary reinforced concrete members, thereby achieving the purpose of fully saving materials. The structure is simple, easy to process, and more economical.

[0033] In addition, shear connection holes 6 are provided in the web 3, and the concrete structural layer 5 covers the shear connection holes 6. After the concrete is poured, a PBL (Problem-Based Learning) connector is formed between the concrete structural layer 5 and the web 3, thereby enhancing the overall effect of the concrete and the steel web 3.

[0034] In order to improve the assembly performance of the composite beam, bolt holes 7 are opened on the webs 3 near the two ends of the upper wing plate 1 and the lower wing plate 2 for assembly connection with other components by high-strength bolts to transmit shear force. The bolt holes 7 are located on the side where the two webs 3 are separated from each other, and the shear connection holes 6 are located on the side where the two webs 3 are close to each other. The end faces of the concrete structure layer 5 are respectively located between the bolt holes 7 and the shear connection holes 6 of the two webs 3.

[0035] Therefore, the present invention,

[0036] 1) Save materials by replacing the web of the H-shaped steel with restrained steel bars and reducing the thickness of the upper and lower flanges of the H-shaped steel beam. The components can be designed according to the steel content ratio of ordinary reinforced concrete components, thus achieving the purpose of fully saving materials and better economy.

[0037] 2) High production efficiency, simple structure, easy processing. The factory adopts a variety of mature methods to process steel components. The components are placed on their sides, and the upper and lower flanges of the components can be used as side molds. No molds are required, and concrete can be poured in one go, which has high production efficiency and low production costs.

[0038] 3) Better integrity. The restraint steel bars are connected to the upper and lower flanges, acting as shear members connecting the flange steel plates and concrete. The restraint steel bars replace the steel webs, turning the concrete from two independent parts into a whole. The restraint steel bars can directly participate in the shear resistance of the composite member.

[0039] 4) It has a wide range of applications and can make full use of existing mature steel structure connection nodes to connect with conventional steel columns and steel tube concrete columns. The upper part of the beam is a steel flange, which can be used with various types of prefabricated floor slabs, making the application range of this beam wide; because the concrete between the flanges is a whole, it can be used with prestressing technology, which further expands the application range of this beam.

[0040] Although the embodiments of the present invention have been shown and described, it is apparent to those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and basis of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Therefore, the embodiments of the present invention are merely illustrative examples of the present invention. No matter from which point of view, the embodiments of the present invention do not constitute a limitation on the present invention.

Claims

1. A constrained steel-concrete composite beam structure, characterized in that: The invention comprises an upper wing plate and a lower wing plate arranged in parallel with each other, and a plurality of webs are spaced apart between the upper wing plate and the lower wing plate, wherein the webs are perpendicular to the upper wing plate and the lower wing plate, so that the upper wing plate, the lower wing plate and the webs form an H-shape as a whole; restraining steel bars are arranged between the upper wing plate and the lower wing plate in the area corresponding to the intervals between adjacent webs, wherein the restraining steel bars are fixedly connected to the upper wing plate and the lower wing plate respectively, and a concrete structural layer covering the restraining steel bars and part or all of the webs is cast between the upper wing plate and the lower wing plate; Among them, the restraining steel bars include two steel meshes arranged on both sides of the web, the steel meshes include multiple stacked corrugated steel bars, the corrugated steel bars include crest sections, diagonal bracing sections and trough sections, the crest sections and trough sections of the multiple corrugated steel bars are staggered, and the crest sections of the corrugated steel bars are connected to the upper wing plate, and the trough sections are connected to the lower wing plate, and the crest sections of the corrugated steel bars are inclined to one side of the width direction of the composite beam, and the trough sections are inclined to the other side of the width direction of the composite beam, so that there is an angle between the crest sections and trough sections of the corrugated steel bars and the length direction of the composite beam.

2. The constrained steel bar-concrete composite beam structure according to claim 1, characterized in that: The included angle θ between the diagonal bracing section and the length direction of the composite beam is 45°.

3. The constrained steel bar-concrete composite beam structure according to claim 1, characterized in that: The connection area between the crest section of the corrugated steel bar and the upper wing plate or the connection area between the trough section and the lower wing plate forms a steel reinforcement section, and the area between adjacent steel reinforcement sections forms a non-reinforced section. The ratio of the length of the non-reinforced section to the thickness of the upper wing plate and the lower wing plate should meet the following requirements: Where L2 is the length of the non-stiffened section, t is the thickness of the upper and lower wing panels, and f y is the yield strength of the flange plate.

4. The constrained steel bar-concrete composite beam structure according to claim 1, characterized in that: The distance between the two peaks of the corrugated steel bar is the wave width. When the height of the composite beam H≤500mm, the wave width range includes two wave peak sections, and satisfies 2h+L1=2L1+3L2, and L1≥L2. When the height of the composite beam 500mm<H≤700mm, the wave width range includes three wave peak sections, and satisfies 2h+L1=3L1+4L2, and L1≥L2. When the height of the composite beam H>700mm, the wave width range includes four wave peak sections, and satisfies 2h+L1=4L1+5L2, and L1≥L2, wherein L1 is the length of the steel bar reinforcement section, and h is the net distance between the upper wing plate and the lower wing plate.

5. The constrained steel bar-concrete composite beam structure according to claim 1, characterized in that: Shear connection holes are opened on the web, and the shear connection holes are covered by the concrete structure layer.

6. The constrained steel bar-concrete composite beam structure according to claim 1, characterized in that: Bolt holes are provided on the webs near both ends of the upper wing plate and the lower wing plate, the bolt holes are located on the side where the two webs are separated, the shear connection holes are located on the side where the two webs are close to each other, and the end faces of the concrete structure layer are respectively located between the bolt holes and the shear connection holes of the two webs.

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